设计模式 UML & java code
A: 创造性模式
1. 工厂方法模式(FactoryMethod)
1.1 类图
1.2 代码1
public interface Pet{
public String petSound();
}
public class Cat implements Pet {
@Override
public String petSound() {
return "Meaw Meaw...";
}
}
public class Dog implements Pet {
@Override
public String petSound() {
return "Bow Bow...";
}
}
public class PetFactory {
public Pet getPet(String petType){
Pet pet = null;
if("Bow".equals(petType)){
pet = new Dog();
}else if("Meaw".equals(petType)){
pet = new Cat();
}
return pet;
}
}
public class SampleFactoryMethod {
public static void main(String[] args){
PetFactory factory = new PetFactory();
Pet pet = factory.getPet("Bow");
System.out.println(pet.petSound());
}
}
View Code
代码2 (泛型)
public abstract class Product { public void method1(){
//
};
public abstract void method2();
}
public class ConcreateProduct1 extends Product {
@Override
public void method2() {
}
}
public class ConcreateProduct2 extends Product {
@Override
public void method2() {
}
}
public abstract class Creator {
public abstract <T extends Product> T createProduct(Class<T> c);
}
public class ConcreateCreator extends Creator {
@Override
public <T extends Product> T createProduct(Class<T> c) {
Product instance = null;
try {
instance = (Product) Class.forName(c.getName()).newInstance();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return (T)instance;
}
}
public class Client {
public static void main(String[] args){
Creator creator = new ConcreateCreator();
ConcreateProduct1 product1 = creator.createProduct(ConcreateProduct1.class);
}
}
View Code
2. 抽象工厂模式(AbstractFactory)
2.1 类图
2.2 代码
package org.rocky.learn.designPattern.AbstractFactory;/**
* Created by admin on 2018/3/20.
*/
public abstract class Car {
public abstract Parts getWheels();
public abstract Parts getMirrors();
public abstract Parts getEngine();
public abstract Parts getBody();
}
package org.rocky.learn.designPattern.AbstractFactory;
/**
* Created by admin on 2018/3/20.
*/
public class Parts {
private String specification;
public Parts(String specification){
this.specification = specification;
}
public String getSpecification(){
return specification;
}
}
package org.rocky.learn.designPattern.AbstractFactory;
/**
* Created by admin on 2018/3/20.
*/
public class BenQ extends Car {
@Override
public Parts getWheels() {
return new Parts("BenQ Wheels");
}
@Override
public Parts getMirrors() {
return new Parts("BenQ Mirriors");
}
@Override
public Parts getEngine() {
return new Parts("BenQ Engine");
}
@Override
public Parts getBody() {
return new Parts("BenQ body");
}
}
package org.rocky.learn.designPattern.AbstractFactory;
/**
* Created by admin on 2018/3/20.
*/
public class BMW extends Car {
@Override
public Parts getWheels() {
return new Parts("BMW Wheels");
}
@Override
public Parts getMirrors() {
return new Parts("BMW Mirrors");
}
@Override
public Parts getEngine() {
return new Parts("BMW Engine");
}
@Override
public Parts getBody() {
return new Parts("BMW Body");
}
}
package org.rocky.learn.designPattern.AbstractFactory;
/**
* Created by admin on 2018/3/20.
*/
public class CarType {
private Car car;
public Car getCar(String carType){
if("BenQ".equals(carType)){
car = new BenQ();
}else if("BMW".equals(carType)){
car = new BMW();
}
return car;
}
public static void main(String[] args){
CarType carType = new CarType();
Car benQ = carType.getCar("BenQ");
System.out.println(benQ.getWheels().getSpecification());
System.out.println(benQ.getMirrors().getSpecification());
System.out.println(benQ.getEngine().getSpecification());
System.out.println(benQ.getBody().getSpecification());
}
}
View Code
3. 建造者模式(Builder)
克隆对象分为浅层复制和深层复制
3.1 类图
3.2 代码1
public interface CarPlan { public void setBase(String basement);
public void setWheels(String structure);
}
public class Car implements CarPlan {
private String base;
private String wheels;
@Override
public void setBase(String basement) {
this.base = basement;
}
@Override
public void setWheels(String structure) {
this.wheels = structure;
}
@Override
public String toString() {
return "Car{" +
"base='" + base + '\'' +
", wheels='" + wheels + '\'' +
'}';
}
}
public interface CarBuilder {
public void buildBase();
public void buildWheels();
public Car getCar();
}
public class LowPriceCarBuilder implements CarBuilder {
private Car car;
public LowPriceCarBuilder(){
car = new Car();
}
@Override
public void buildBase() {
car.setBase("Low Price Car Base Build");
}
@Override
public void buildWheels() {
car.setWheels("Low Price Car Wheels build");
}
@Override
public Car getCar() {
return this.car;
}
}
public class MechanicalEngineer {
private CarBuilder carBuilder;
public MechanicalEngineer(CarBuilder carBuilder){
this.carBuilder = carBuilder;
}
public Car getCar(){
return carBuilder.getCar();
}
public void buildCar(){
carBuilder.buildBase();
carBuilder.buildWheels();
}
public static void main(String[] args){
CarBuilder lowPriceCarBuilder = new LowPriceCarBuilder();
MechanicalEngineer mechanicalEngineer = new MechanicalEngineer(lowPriceCarBuilder);
mechanicalEngineer.buildCar();
Car car = mechanicalEngineer.getCar();
System.out.print("Builder constructor car.."+car);
}
}
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java的api中 StringBuilder 和 StringBuffer是使用的生成器模式实例
代码2
public abstract class House { protected Floor floor;
protected Walls walls;
protected Roof roof;
public Floor getFloor() {
return floor;
}
public void setFloor(Floor floor) {
this.floor = floor;
}
public Walls getWalls() {
return walls;
}
public void setWalls(Walls walls) {
this.walls = walls;
}
public Roof getRoof() {
return roof;
}
public void setRoof(Roof roof) {
this.roof = roof;
}
public abstract String getRepresentation();
}
public interface Floor {
public String getRepresentation();
}
public interface Walls {
public String getRepresentation();
}
public interface Roof {
public String getRepresentation();
}
package org.rocky.learn.designPattern.BuilderPattern2;
/**
* Created by admin on 2018/3/20.
*/
public class WoodHouse extends House {
@Override
public String getRepresentation() {
return "Build Wood House";
}
}
package org.rocky.learn.designPattern.BuilderPattern2;
/**
* Created by admin on 2018/3/20.
*/
public class WoodFloor implements Floor {
@Override
public String getRepresentation() {
return "Build Wood Floor..";
}
}
public class WoodWalls implements Walls {
@Override
public String getRepresentation() {
return "Build Wood Walls";
}
}
public class WoodRoof implements Roof {
@Override
public String getRepresentation() {
return "Build Wood Roof";
}
}
public abstract class HouseBuilder {
protected House house;
protected Floor floor;
protected Walls walls;
protected Roof roof;
public abstract House createHouse();
public abstract Floor createFloor();
public abstract Walls createWalls();
public abstract Roof createRoof();
}
public class WoodBuilder extends HouseBuilder {
@Override
public House createHouse() {
house = new WoodHouse();
return house;
}
@Override
public Floor createFloor() {
floor = new WoodFloor();
return floor;
}
@Override
public Walls createWalls() {
walls = new WoodWalls();
return walls;
}
@Override
public Roof createRoof() {
roof = new WoodRoof();
return roof;
}
}
public class HouseDirector {
public House constructHouse(HouseBuilder houseBuilder){
House house = houseBuilder.createHouse();
System.out.println(house.getRepresentation());
house.setFloor(houseBuilder.createFloor());
System.out.println(house.getFloor().getRepresentation());
house.setWalls(houseBuilder.createWalls());
System.out.println(house.getWalls().getRepresentation());
house.setRoof(houseBuilder.createRoof());
System.out.println(house.getRoof().getRepresentation());
return house;
}
}
public class HouseClient {
public static void main(String[] args){
HouseDirector director = new HouseDirector();
HouseBuilder houseBuilder = new WoodBuilder();
director.constructHouse(houseBuilder);
}
}
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4. 单例模式(Singleton)
4.1 UML类图
4.2 代码1 被动实例化
package org.rocky.learn.designPattern.Singleton;/**
* Created by admin on 2018/3/20.
*/
public class SingletonPassive {
private static SingletonPassive singleton;
private SingletonPassive(){}
public static SingletonPassive getSingleton(){
if(singleton == null){
synchronized (SingletonPassive.class){
if(singleton == null){
singleton = new SingletonPassive();
}
}
}
return singleton;
}
}
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代码2 主动实例化
public class SingletonProactive { private static SingletonProactive singleton = new SingletonProactive();
private SingletonProactive(){}
public static SingletonProactive getSingleton(){
return singleton;
}
}
View Code
5. 原型模式(prototype)
5.1 UML类图
5.2 代码
//浅拷贝package org.rocky.learn.designPattern.PrototypePattern;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by admin on 2018/3/21.
*/
public class Plan implements Cloneable {
//计划名称
private String name;
//任务级别
private int level;
//开始时间
private Date startdate;
//截止时间
private Date enddate;
//执行人员
private List<String> executors = new ArrayList<String>();
@Override
public Plan clone(){
try {
return (Plan) super.clone();
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return null;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getStartdate() {
return startdate;
}
public void setStartdate(Date startdate) {
this.startdate = startdate;
}
public Date getEnddate() {
return enddate;
}
public void setEnddate(Date enddate) {
this.enddate = enddate;
}
public List<String> getExecutors() {
return executors;
}
public void setExecutors(List<String> executors) {
this.executors = executors;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
@Override
public String toString() {
return "[name=" + name + ", level=" + level + ", startdate=" + startdate + ", enddate=" + enddate
+ ", executors=" + executors + "]";
}
}
//client
package org.rocky.learn.designPattern.PrototypePattern;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;
/**
* Created by admin on 2018/3/21.
*/
public class Client {
private static final String format = "YYYY-mm-dd";
public static void main(String[] args) throws ParseException {
List<String> executors = new ArrayList<String>();
executors.add("张三");
executors.add("李四");
Plan plan = new Plan();
plan.setName("重构前端登录界面");
plan.setLevel(1);
plan.setStartdate(new SimpleDateFormat(format).parse("2017-08-07"));
plan.setEnddate(new SimpleDateFormat(format).parse("2017-08-07"));
plan.setExecutors(executors);
Plan plan2 = plan.clone();
plan2.setName("后端接口改造");
plan2.setLevel(2);
plan2.setStartdate(new SimpleDateFormat(format).parse("2017-08-07"));
plan2.setEnddate(new SimpleDateFormat(format).parse("2017-08-07"));
System.out.println("地址是否一样？"+(plan == plan2));
System.out.println("plan.getName() == plan2.getName() "+(plan.getName() == plan2.getName()));
System.out.println("plan.getLevel() == plan2.getLevel() "+(plan.getLevel() == plan2.getLevel()));
System.out.println("plan.getStartdate() == plan2.getStartdate() "+(plan.getStartdate() == plan2.getStartdate()));
System.out.println("plan.getEnddate() == plan2.getEnddate() "+(plan.getEnddate() == plan2.getEnddate()));
System.out.println("plan.getExecutors() == plan2.getExecutors() "+(plan.getExecutors() == plan2.getExecutors()));
System.out.println("plan:"+plan.toString());
System.out.println("plan2:"+plan2.toString());
//plan任务比较重，在给plan添加一个人
executors.add("王五");
plan.setExecutors(executors);
System.out.println();
System.out.println("地址是否一样？"+(plan == plan2));
System.out.println("plan.getName() == plan2.getName() "+(plan.getName() == plan2.getName()));
System.out.println("plan.getLevel() == plan2.getLevel() "+(plan.getLevel() == plan2.getLevel()));
System.out.println("plan.getStartdate() == plan2.getStartdate() "+(plan.getStartdate() == plan2.getStartdate()));
System.out.println("plan.getEnddate() == plan2.getEnddate() "+(plan.getEnddate() == plan2.getEnddate()));
System.out.println("plan.getExecutors() == plan2.getExecutors() "+(plan.getExecutors() == plan2.getExecutors()));
System.out.println("plan:"+plan.toString());
System.out.println("plan2:"+plan2.toString());
}
}
//深拷贝 clone方法
package org.rocky.learn.designPattern.PrototypePattern;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by admin on 2018/3/21.
*/
public class PlanDeeper {
//计划名称
private String name;
//任务级别
private int level;
//开始时间
private Date startdate;
//截止时间
private Date enddate;
//执行人员
private List<String> executors = new ArrayList<String>();
@Override
public Plan clone(){
try {
Plan plan = (Plan) super.clone();
//引用类型的属性，需要处理
if(this.getExecutors() != null){
List<String> _executors = new ArrayList<String>();
for(String s : this.getExecutors()){
_executors.add(s);
}
plan.setExecutors(_executors);
}
return plan;
} catch (CloneNotSupportedException e) {
e.printStackTrace();
}
return null;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getStartdate() {
return startdate;
}
public void setStartdate(Date startdate) {
this.startdate = startdate;
}
public Date getEnddate() {
return enddate;
}
public void setEnddate(Date enddate) {
this.enddate = enddate;
}
public List<String> getExecutors() {
return executors;
}
public void setExecutors(List<String> executors) {
this.executors = executors;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
@Override
public String toString() {
return "[name=" + name + ", level=" + level + ", startdate=" + startdate + ", enddate=" + enddate
+ ", executors=" + executors + "]";
}
}
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说明 见 3-2
B: 结构型模式
6.适配器模式(Adaptor)
6.1 UML类图
有两种应用适配器模式的方法
使用继承【类适配器】
使用关联【对象适配器】
6.2 代码
a: 使用继承【类适配器】
public class Plug { private String specification;
protected String getInput(){
return specification;
}
public Plug(){
specification = "3-Pin";
}
}
public interface Socket {
public String getInput();
}
public class ExpansionAdaptor extends Plug implements Socket {
@Override
public String getInput() {
String input = super.getInput();
input += " converted to 2-Pin";
return input;
}
}
public class Client {
public static void main(String[] args){
Socket socket = new ExpansionAdaptor();
String input = socket.getInput();
System.out.print(input);
}
}
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b: 使用关联【对象适配器】
public class ExpansionAdapter implements Socket{
private Plug plug;
public ExpansionAdapter(Plug p){
plug = p;
}
@Override
public String getInput() {
String input = plug.getInput();
input += " power converted to 2-Pin";
return input;
}
}
public static void main(String[] args){
Socket socket = new ExpansionAdapter(new Plug());
String input = socket.getInput();
System.out.println(input);
}
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7. 桥接模式
7.1 UML图
7.2 代码
public interface TV { public void powerOn();
public void powerOff();
public void changeChannel(int channel);
}
public class GoogleTV implements TV {
@Override
public void powerOn() {
}
@Override
public void powerOff() {
}
@Override
public void changeChannel(int channel) {
}
}
public class AppleTV implements TV {
@Override
public void powerOn() {
}
@Override
public void powerOff() {
}
@Override
public void changeChannel(int channel) {
}
}
public abstract class TVRemoteControl {
private TV implementor;
public void powerOn(){
implementor.powerOn();
}
public void powerOff(){
implementor.powerOff();
}
public void setChannel(int channel){
implementor.changeChannel(channel);
}
}
public class ConcreteTVRemoteControl extends TVRemoteControl {
private int currentChannel;
public void nextChannel(){
currentChannel++;
setChannel(currentChannel);
}
public void previousChannel(){
currentChannel--;
setChannel(currentChannel);
}
}
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8. 组合模式
8.1 UML类图
8.2 代码
public interface FileComponent { public void printName();
}
public class LeafFile implements FileComponent {
private String fileName;
public LeafFile(String name){
fileName = name;
}
@Override
public void printName() {
System.out.println(fileName);
}
}
public class Directory implements FileComponent {
private String fileName;
public Directory(String name){
fileName = name;
}
private List files = new ArrayList();
public void add(FileComponent component){
files.add(component);
}
@Override
public void printName() {
System.out.println("Directory name : "+ fileName);
for(int i=0; i< files.size(); i++){
FileComponent component = (FileComponent) files.get(i);
component.printName();
}
}
}
public class CompositeDemo {
public static void main(String[] args){
Directory one = new Directory("dir-1");
Directory two = new Directory("dir-2");
Directory three = new Directory("dir-3");
LeafFile a = new LeafFile("file-a");
LeafFile b = new LeafFile("file-b");
LeafFile c = new LeafFile("file-c");
LeafFile d = new LeafFile("file-d");
one.add(a);
one.add(two);
two.add(b);
two.add(c);
two.add(three);
three.add(d);
one.printName();
}
}
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9. 装饰模式
9.1 UML类图
9.2 代码1
public interface House { public String makeHouse();
}
public class SimpleHouse implements House {
@Override
public String makeHouse() {
return "Base House";
}
}
public class HouseDecorator implements House {
protected House house;
public HouseDecorator(House house){
this.house = house;
}
@Override
public String makeHouse() {
return house.makeHouse();
}
}
public class ColorDecorator extends HouseDecorator {
public ColorDecorator(House house){
super(house);
}
private String addColor(){
return " + red color";
}
public String makeHouse(){
return house.makeHouse() + addColor();
}
}
public class LightsDecorator extends HouseDecorator {
public LightsDecorator(House house) {
super(house);
}
private String addLights(){
return " + LED lights";
}
public String makeHouse(){
return house.makeHouse() + addLights();
}
}
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java API中 IO流用到装饰模式 (new BufferedReader(new FileReader("a.txt")))
代码2
public interface Coffee { public double getCosts();//加格
public String getIngredients();//成分
}
public class SimpleCoffee implements Coffee {
@Override
public double getCosts() {
return 1;
}
@Override
public String getIngredients() {
return "Coffee";
}
}
public abstract class CoffeeDecorator implements Coffee {
protected final Coffee decoratedCoffee;
protected String ingredientSeparator = ",";
public CoffeeDecorator(Coffee coffee){
decoratedCoffee = coffee;
}
@Override
public double getCosts() {
return decoratedCoffee.getCosts();
}
@Override
public String getIngredients() {
return decoratedCoffee.getIngredients();
}
}
public class Milk extends CoffeeDecorator {
public Milk(Coffee coffee) {
super(coffee);
}
public double getCost(){
return super.getCosts() + 0.5;
}
public String getIngredients(){
return super.getIngredients() + ingredientSeparator + " Milk";
}
}
public class Whip extends CoffeeDecorator {
public Whip(Coffee coffee) {
super(coffee);
}
public double getCosts(){
return super.getCosts() + 0.7;
}
public String getIngredients(){
return super.getIngredients() + ingredientSeparator + " Whip";
}
}
public class Sprinkles extends CoffeeDecorator {
public Sprinkles(Coffee coffee) {
super(coffee);
}
public double getCosts(){
return super.getCosts() + 0.2;
}
public String getIngredients(){
return super.getIngredients() + ingredientSeparator + " Sprinkles";
}
}
public class DecoratorTest
{
public static void main(String[] args){
Coffee c = new SimpleCoffee();
System.out.println("Cost:"+c.getCosts() + ",ingredients:"+ c.getIngredients());
c = new Milk(c);
System.out.println("Cost:"+c.getCosts() + ",ingredients:"+ c.getIngredients());
c = new Whip(c);
System.out.println("Cost:"+c.getCosts() + ",ingredients:"+ c.getIngredients());
c = new Sprinkles(c);
System.out.println("Cost:"+c.getCosts() + ",ingredients:"+ c.getIngredients());
}
}
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10. 门面模式
10.1 UML类图
10.2 代码
public class GUIMenu { public void drawMenuButtons(){}
}
public class GUITitleBar {
public void showTitleBar(String caption){}
}
public class GUIContent {
public void showButtons(){}
public void showTextFields(){}
public void setDefaultValues(){}
}
public class MyGUI {
private GUIContent guiContent;
private GUIMenu guiMenu;
private GUITitleBar guiTitleBar;
public MyGUI(){
guiContent = new GUIContent();
guiMenu = new GUIMenu();
guiTitleBar = new GUITitleBar();
}
public void drawGUI(){
guiContent.setDefaultValues();
guiContent.showButtons();
guiContent.showTextFields();
guiTitleBar.showTitleBar("My gui");
guiMenu.drawMenuButtons();
}
}
public class TestFacade {
public static void main(String[] args){
MyGUI myGUI = new MyGUI();
myGUI.drawGUI();
}
}
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11. 代理模式
11.1 UML类图
11.2 代码
public interface Image { public void showImage();
}
public class RealImage implements Image {
public RealImage(URL url){
loadImage(url);
}
public void loadImage(URL url) {
}
@Override
public void showImage() {
}
}
public class ProxyImage implements Image {
private URL url;
public ProxyImage(URL url){
this.url = url;
}
@Override
public void showImage() {
RealImage realImage = new RealImage(url);
realImage.showImage();
}
}
public class ProxyTest {
public static void main(String[] args){
try {
Image image1 = new ProxyImage(new URL("http","ip","TestFloder/1.jpg"));
Image image2 = new ProxyImage(new URL("http","ip","TestFloder/2.jpg"));
Image image3 = new ProxyImage(new URL("http","ip","TestFloder/3.jpg"));
image1.showImage();//被加载到内存中
} catch (MalformedURLException e) {
e.printStackTrace();
}
}
}
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12. 享元模式
12.1 UML类图
对象属性分为内蕴状态 和 外蕴状态
12.2 代码
public interface MyShape { public void draw(Graphics g, int x, int y, int width, int height, Color color, boolean fill, String font);
}
public class MyOval implements MyShape {
private String label;
public MyOval(String label){
this.label = label;
}
@Override
public void draw(Graphics oval, int x, int y, int width, int height, Color color, boolean fill, String font) {
oval.setColor(color);
oval.drawOval(x, y, width, height);
oval.setFont(new Font(font, 12, 12));
oval.drawString(label, x+(width/2), y);
if(fill) oval.fillOval(x, y, width, height);
}
}
public class MyRectangle implements MyShape {
private String label;
public MyRectangle(String label){
this.label = label;
}
@Override
public void draw(Graphics rectangle, int x, int y, int width, int height, Color color, boolean fill, String font) {
rectangle.setColor(color);
rectangle.drawRect(x, y, width, height);
rectangle.setFont(new Font(font, 12, 12));
rectangle.drawString(label, x+(width/2), y);
if(fill) rectangle.fillRect(x, y, width, height);
}
}
public class ShapeFactory {
private static final HashMap shapes = new HashMap();
public static MyShape getShape(String label){
MyShape concreteShape = (MyShape) shapes.get(label);
if(concreteShape == null){
if("R".equals(label)){
concreteShape = new MyRectangle(label);
}else if("O".equals(label)){
concreteShape = new MyOval(label);
}
}
return concreteShape;
}
}
public class Client extends JFrame{
private static final int WIDTH = 300;
private static final int HEIGHT = 300;
private static final String[] shapes = {"R", "O"};
private static final Color colors[] = {Color.blue, Color.black, Color.red};
private static final boolean fill[] = {true, false};
private static final String font[] = {"Arial", "Courier"};
public Client(){
Container contentPane = getContentPane();
JButton startButton = new JButton("Draw Shapes");
final JPanel panel = new JPanel();
contentPane.add(panel, BorderLayout.CENTER);
contentPane.add(startButton, BorderLayout.SOUTH);
setSize(WIDTH, HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
startButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
Graphics graphics = panel.getGraphics();
MyShape shape = ShapeFactory.getShape(getRandomShape());
shape.draw(graphics, getRandomX(), getRandomY(), getRandomWidth(), getRandomHeight(),
getRandomColor(), getRandomFill(), getRandomFont());
}
});
}
private String getRandomShape(){
return shapes[(int)Math.random()*shapes.length];
}
private int getRandomX(){
return (int) (Math.random()*WIDTH);
}
private int getRandomY(){
return (int) (Math.random()*HEIGHT);
}
private int getRandomWidth(){
return (int) (Math.random()*(getWidth()/7));
}
private int getRandomHeight(){
return (int) (Math.random()*(getHeight()/7));
}
private Color getRandomColor(){
return colors[(int) (Math.random()*colors.length)];
}
private boolean getRandomFill(){
return fill[(int) (Math.random()*fill.length)];
}
private String getRandomFont(){
return font[(int) (Math.random()*font.length)];
}
public static void main(String[] args){
Client client = new Client();
}
}
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C: 行为型模式
处理不同的对象间的通信关系
13. 职责链模式
13.1 UML类图
13.2 代码
列子： Servlet过滤器和JAVA异常处理机制
public abstract class Logger { public static int ERR = 3;
public static int NOTICE = 5;
public static int DEBUG = 7;
protected int mask;
//链中的下一个元素
protected Logger next;
public Logger setNext(Logger log){
next = log;
return log;
}
public void message(String msg, int priority){
if(priority <= mask){
writeMessage(msg);
}
if(next != null){
next.message(msg, priority);
}
}
protected abstract void writeMessage(String msg);
}
public class StdoutLogger extends Logger {
public StdoutLogger(int mask){
this.mask = mask;
}
@Override
protected void writeMessage(String msg) {
System.out.println("Writing to stdout:"+msg);
}
}
public class EmailLogger extends Logger {
public EmailLogger(int mask){
this.mask = mask;
}
@Override
protected void writeMessage(String msg) {
System.out.println("Sending via email:"+msg);
}
}
public class StderrLogger extends Logger {
public StderrLogger(int mask){
this.mask = mask;
}
@Override
protected void writeMessage(String msg) {
System.err.println("Sending to stderr:"+msg);
}
}
public class ChainOfResponsibilityExample {
public static void main(String[] args){
//创建职责链
Logger logger, logger1, logger2;
logger = new StdoutLogger(Logger.DEBUG);
logger1 = logger.setNext(new EmailLogger(Logger.NOTICE));
logger2 = logger1.setNext(new StderrLogger(Logger.ERR));
//由StdoutLogger进行处理
logger.message("Entering function a:", Logger.DEBUG);
//由StdoutLogger 和 EmailLogger进行处理
logger.message("Step 1 finished", Logger.NOTICE);
//由三个处理器一起完成
logger.message("An error has occurred", Logger.ERR);
}
}
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14. 命令模式
14.1 UML类图
14.2 代码
public interface Command { void execute();
}
/**接收类*/
public class AirConditioner {
public AirConditioner(){}
public void start(){
System.out.println("The airconditioner is on");
}
public void stop(){
System.out.println("The airconditioner is off");
}
}
/**调用类*/
public class Switch {
private List<Command> commandHistory = new ArrayList<Command>();
public Switch(){}
public void storeAndExecute(Command command){
this.commandHistory.add(command);
command.execute();
}
}
public class StartCommand implements Command {
private AirConditioner theAirConditioner;
public StartCommand(AirConditioner airConditioner){
theAirConditioner = airConditioner;
}
@Override
public void execute() {
theAirConditioner.start();
}
}
public class StopCommand implements Command {
private AirConditioner theAirConditioner;
public StopCommand(AirConditioner airConditioner){
theAirConditioner = airConditioner;
}
@Override
public void execute() {
theAirConditioner.stop();
}
}
public class PressSwitch {
public static void main(String[] args){
AirConditioner airConditioner = new AirConditioner();
Command startCommand = new StartCommand(airConditioner);
StopCommand stopCommand = new StopCommand(airConditioner);
Switch sw = new Switch();
sw.storeAndExecute(startCommand);
sw.storeAndExecute(stopCommand);
}
}
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15. 解释器模式
15.1 UML类图
15.2 代码
public abstract class Expression { public abstract boolean interpret(String str);
}
public class TerminalExpression extends Expression {
private String literal;
public TerminalExpression(String str){
literal = str;
}
@Override
public boolean interpret(String str) {
StringTokenizer st = new StringTokenizer(str);
while (st.hasMoreTokens()){
String s = st.nextToken();
if(s.equals(literal)){
return true;
}
}
return false;
}
}
public class OrExpression extends Expression {
private Expression expression1 = null;
private Expression expression2 = null;
public OrExpression(Expression expression1, Expression expression2){
this.expression1 = expression1;
this.expression2 = expression2;
}
@Override
public boolean interpret(String str) {
return expression1.interpret(str) || expression2.interpret(str);
}
}
public class AndExpression extends Expression {
private Expression expression1 = null;
private Expression expression2 = null;
public AndExpression(Expression expression1, Expression expression2){
this.expression1 = expression1;
this.expression2 = expression2;
}
@Override
public boolean interpret(String str) {
return expression1.interpret(str) && expression2.interpret(str);
}
}
public class InterpretTest {
static Expression buildInterpretTree(){
//字面含义
Expression terminal1 = new TerminalExpression("Name1");
Expression terminal2 = new TerminalExpression("Name2");
Expression terminal3 = new TerminalExpression("Name3");
Expression terminal4 = new TerminalExpression("Name4");
Expression alternation1 = new OrExpression(terminal2, terminal3);
Expression alternation2 = new OrExpression(terminal1, alternation1);
Expression expression = new AndExpression(terminal4, alternation2);
return expression;
}
public static void main(String[] args){
String context = "Name4 Name3";
Expression expression = buildInterpretTree();
System.out.println(context + " is "+ expression.interpret(context));
}
}
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16. 迭代器模式
16.1 UML类图
16.2 代码
public class Item { String itemName;
float itemPrice;
public Item(String itemName, float itemPrice){
this.itemName = itemName;
this.itemPrice = itemPrice;
}
public String toString(){
return itemName + ": "+itemPrice;
}
}
public class Menu {
List<Item> menuItems;
public Menu(){
menuItems = new ArrayList<Item>();
}
public void addItem(Item item){
menuItems.add(item);
}
public Iterator<Item> createIterator(){
return new MenuIterator();
}
class MenuIterator implements Iterator<Item> {
int currentIndex = 0;
public boolean hasNext(){
if(currentIndex >= menuItems.size())
return false;
else
return true;
}
public Item first(){
return menuItems.get(0);
}
public Item currentItem(){
return menuItems.get(currentIndex);
}
public Item next(){
return menuItems.get(currentIndex++);
}
public void remove(){
menuItems.remove(--currentIndex);
}
}
}
public class IteratorTest {
public static void main(String[] args){
Item item1 = new Item("item1", 10f);
Item item2 = new Item("item2", 20f);
Item item3 = new Item("item3", 30f);
Menu menu = new Menu();
menu.addItem(item1);
menu.addItem(item2);
menu.addItem(item3);
System.out.println("Displaying menu...");
Iterator<Item> iterator = menu.createIterator();
while (iterator.hasNext()){
Item item = iterator.next();
System.out.println(item);
}
System.out.println("Removing the last item returned.");
iterator.remove();
System.out.println("Displaying menu...");
iterator = menu.createIterator();
while (iterator.hasNext()){
Item item = iterator.next();
System.out.println(item);
}
}
}
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17. 中介者模式
17.1 UML类图
例子 聊天程序-群聊
17.2 代码
public class Mediator { Buyer indianBuyer;
Buyer frenchBuyer;
AmericanSeller americanSeller;
DollarConverter dollarConverter;
public Mediator(){}
public void registerIndianBuyer(Buyer indianBuyer){
this.indianBuyer = indianBuyer;
}
public void registerFrenchBuyer(Buyer frenchBuyer){
this.frenchBuyer = frenchBuyer;
}
public void registerAmericanSeller(AmericanSeller americanSeller){
this.americanSeller = americanSeller;
}
public void registerDollarConverter(DollarConverter dollarConverter){
this.dollarConverter = dollarConverter;
}
public boolean placeBid(float bid, String unitOfCurrency){
float dollars = dollarConverter.convertCurrencyToDollars(bid, unitOfCurrency);
return americanSeller.isBidAccepted(dollars);
}
}
public class Buyer {
Mediator mediator;
String unitOfCurrency;
public Buyer(Mediator mediator, String unitOfCurrency){
this.mediator = mediator;
this.unitOfCurrency = unitOfCurrency;
}
public boolean attemptToPurchase(float bid){
System.out.println("Buyer attempting a bid of "+ bid + " " + unitOfCurrency);
return this.mediator.placeBid(bid, unitOfCurrency);
}
}
public class IndianBuyer extends Buyer {
public IndianBuyer(Mediator mediator) {
super(mediator, "INR");
this.mediator.registerIndianBuyer(this);
}
}
public class FrenchBuyer extends Buyer {
public FrenchBuyer(Mediator mediator) {
super(mediator, "EURO");
this.mediator.registerFrenchBuyer(this);
}
}
public class AmericanSeller {
Mediator mediator;
float priceInDollars;
public AmericanSeller(Mediator mediator, float priceInDollars){
this.mediator = mediator;
this.priceInDollars = priceInDollars;
this.mediator.registerAmericanSeller(this);
}
public boolean isBidAccepted(float bidInDollars){
if(bidInDollars >= priceInDollars){
System.out.println("Seller accepts bid of "+ bidInDollars + " dollars\n");
return true;
}else{
System.out.println("Seller rejects bid of " + bidInDollars + " dollars\n");
return false;
}
}
}
public class DollarConverter {
Mediator mediator;
public static final float DOLLAR_UNIT = 1.0f;
public static final float EURO_UNIT = 0.7f;
public static final float INR_UNIT = 45.0f;
public DollarConverter(Mediator mediator){
this.mediator = mediator;
this.mediator.registerDollarConverter(this);
}
private float convertEurosToDollars(float euros){
float dollars = euros * (DOLLAR_UNIT/EURO_UNIT);
System.out.println("Converting "+ euros + " euros to "+ dollars + " dollars");
return dollars;
}
private float convertInrToDollars(float inr){
float dollars = inr * (DOLLAR_UNIT/INR_UNIT);
System.out.println("Converting "+ inr + " inr to "+ dollars + " dollars");
return dollars;
}
public float convertCurrencyToDollars(float amount, String unitOfCurrency){
if("INR".equals(unitOfCurrency)){
return convertInrToDollars(amount);
}else
return convertEurosToDollars(amount);
}
}
public class MediatorTest {
public static void main(String[] args){
Mediator mediator = new Mediator();
Buyer indianBuyer = new IndianBuyer(mediator);
Buyer frenchBuyer = new FrenchBuyer(mediator);
float sellingPriceInDollars = 10.0f;
AmericanSeller americanSeller = new AmericanSeller(mediator, sellingPriceInDollars);
DollarConverter dollarConverter = new DollarConverter(mediator);
float indianBidInInr = 55.0f;
while (!indianBuyer.attemptToPurchase(indianBidInInr)){
indianBidInInr += 15.0f;
}
float frenchBidInEuros = 3.0f;
while (!frenchBuyer.attemptToPurchase(frenchBidInEuros)){
frenchBidInEuros += 1.5f;
}
}
}
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18. 备忘录模式
18.1 UML类图
18.2 代码
/*** 备忘录需要能够保存编辑内容 这里使用state代表
* Created by admin on 2018/3/28.
*/
public class Memento {
private String state;
public Memento(String stateToSave){
state = stateToSave;
}
public String getSavedState(){
return state;
}
}
/**
* 管理者需要处理在何时、为何对发起者进行保存和回滚
* Created by admin on 2018/3/28.
*/
public class Caretaker {
private List<Memento> savedState = new ArrayList<Memento>();
public void addMememto(Memento memento){
savedState.add(memento);
}
public Memento getMemento(int index){
return savedState.get(index);
}
}
/**
* 发起者 也会保存不会在备忘录中保存的数据
* Created by admin on 2018/3/28.
*/
public class Originator {
private String state;
public void setState(String state){
System.out.println("Setting state to "+state);
this.state = state;
}
public Memento saveToMemento(){
System.out.println("Saving "+state+" to Memento");
return new Memento(state);
}
public void restoreFromMemento(Memento memento){
state = memento.getSavedState();
System.out.println("Restoring state "+state+" from Memento");
}
}
public class MementoTest {
public static void main(String[] args){
Caretaker caretaker = new Caretaker();
Originator originator = new Originator();
originator.setState("State1");
originator.setState("State2");
caretaker.addMememto(originator.saveToMemento());
originator.setState("State3");
caretaker.addMememto(originator.saveToMemento());
originator.restoreFromMemento(caretaker.getMemento(0));
}
}
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18.3 多个状态
package org.rocky.learn.designPattern.mementoMap;/**
* @Author: rocky
* @Date: Created in 2018/5/11.
*/
public class Originator {
private String state1;
private String state2;
private String state3;
//创建一个备忘录
public Memento createMememto(){
return new Memento(BeanUtils.backupProp(this));
}
//恢复一个备忘录
public void restoreMemento(Memento memento){
BeanUtils.restoreProp(this, memento.getStateMap());
}
public String getState1() {
return state1;
}
public void setState1(String state1) {
this.state1 = state1;
}
public String getState2() {
return state2;
}
public void setState2(String state2) {
this.state2 = state2;
}
public String getState3() {
return state3;
}
public void setState3(String state3) {
this.state3 = state3;
}
public String toString(){
return "state1="+state1+",state2="+state2+",state3="+state3;
}
}
public class Memento {
private HashMap<String, Object> stateMap;
public Memento(HashMap<String, Object> map){
this.stateMap = map;
}
public HashMap<String, Object> getStateMap() {
return stateMap;
}
public void setStateMap(HashMap<String, Object> stateMap) {
this.stateMap = stateMap;
}
}
package org.rocky.learn.designPattern.mementoMap;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Observer;
/**
* @Author: rocky
* @Date: Created in 2018/5/11.
*/
public class BeanUtils {
//把bean的所有属性和值放入HashMap中
public static HashMap<String, Object> backupProp(Object bean){
HashMap<String, Object> result = new HashMap<>();
try {
//获得bean描述
BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
//获得属性描述
PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
//遍历所有属性
for(PropertyDescriptor propertyDescriptor : propertyDescriptors){
//属相名称
String fieldName = propertyDescriptor.getName();
//读取属性的方法
Method readMethod = propertyDescriptor.getReadMethod();
//属性值
// Object value2 = propertyDescriptor.getValue(fieldName);
Object value = readMethod.invoke(bean, new Object[]{});
// System.out.println("value2::"+value2 + ",value::"+value);
if(!fieldName.equalsIgnoreCase("class"))
result.put(fieldName, value);
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
//把hashmap的值放入bean中
public static void restoreProp(Object bean, HashMap<String, Object> map){
try {
//获得bean的描述
BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
//获取属相描述
PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
// 遍历所有属性
for (PropertyDescriptor propertyDescriptor: propertyDescriptors) {
//属性名称
String fieldName = propertyDescriptor.getName();
if(map.containsKey(fieldName)){
//获取写入方法
Method writeMethod = propertyDescriptor.getWriteMethod();
//写入值
writeMethod.invoke(bean, new Object[]{map.get(fieldName)});
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public class Caretaker {
private Memento memento;
public Memento getMemento() {
return memento;
}
public void setMemento(Memento memento) {
this.memento = memento;
}
}
public class Client {
public static void main(String[] args){
//定义发起人
Originator originator = new Originator();
originator.setState1("aaa");
originator.setState2("bbb");
originator.setState3("ccc");
System.out.println(originator);
Caretaker caretaker = new Caretaker();
caretaker.setMemento(originator.createMememto());
originator.setState1("111");
originator.setState2("22");
originator.setState3("333");
System.out.println(originator);
originator.restoreMemento(caretaker.getMemento());
System.out.println(originator);
}
}
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18.4 安全问题
如果创建的对象只允许自己访问，可以使用内部类实现一个空接口
public class Originator {//内部状态
private String state = "";
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
//创建一个备忘录
public IMemento createMemento(){
return new Memento(this.state);
}
//恢复一个备忘录
public void restoreMemento(IMemento _memento){
this.setState(((Memento)_memento).getState());
}
//内置类
private class Memento implements IMemento{
//发起人的内部状态
private String state = "";
//构造函数传递参数
private Memento(String _state){
this.state = _state;
}
private String getState() {
return state;
}
private void setState(String state) {
this.state = state;
}
}
}
public interface IMemento {
}
public class Caretaker {
//备忘录对象
private IMemento memento;
public IMemento getMemento() {
return memento;
}
public void setMemento(IMemento memento) {
this.memento = memento;
}
}
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19 观察者模式
19.1 UML类图
推模式和拉模式
19.2 代码
public interface TemperatureSubject { public void addObserver(TemperatureObserver temperatureObserver);
public void removeObserver(TemperatureObserver temperatureObserver);
public void nofify();
}
public interface TemperatureObserver {
public void update(int temperature);
}
public class TemperatureStation implements TemperatureSubject {
Set<TemperatureObserver> temperatureObservers;
int temperature;
public TemperatureStation(int temperature){
temperatureObservers = new HashSet<TemperatureObserver>();
this.temperature = temperature;
}
@Override
public void addObserver(TemperatureObserver temperatureObserver) {
temperatureObservers.add(temperatureObserver);
}
@Override
public void removeObserver(TemperatureObserver temperatureObserver) {
temperatureObservers.remove(temperatureObserver);
}
@Override
public void nofify() {
Iterator<TemperatureObserver> iterator = temperatureObservers.iterator();
while (iterator.hasNext()){
TemperatureObserver temperatureObserver = iterator.next();
temperatureObserver.update(temperature);
}
}
public void setTemperature(int newTemperature){
System.out.println("Setting temperator to "+newTemperature);
temperature = newTemperature;
nofify();
}
}
public class TemperatureCustomer1 implements TemperatureObserver {
@Override
public void update(int temperature) {
System.out.println("Customer 1 found the temperature as:"+temperature);
}
}
public class TemperatureCustomer2 implements TemperatureObserver {
@Override
public void update(int temperature) {
System.out.println("Customer 2 found the temperature as:"+temperature);
}
}
public class ObserverTest {
public static void main(String[] args){
TemperatureStation temperatureStation = new TemperatureStation(34);
TemperatureCustomer1 tc1 = new TemperatureCustomer1();
TemperatureCustomer2 tc2 = new TemperatureCustomer2();
temperatureStation.addObserver(tc1);
temperatureStation.addObserver(tc2);
temperatureStation.setTemperature(37);
temperatureStation.removeObserver(tc1);
temperatureStation.setTemperature(40);
}
}
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20. 状态模式
20.1 UML类图
20.2 代码
public interface State { public void pressPlay(MusicPlayerContextInterface context);
}
public class StandbyState implements State {
@Override
public void pressPlay(MusicPlayerContextInterface context) {
System.out.println("Converting Standby state to Playing state");
context.setState(new PlayingState());
}
}
public class PlayingState implements State {
@Override
public void pressPlay(MusicPlayerContextInterface context) {
System.out.println("Converting Playing state to Standby state");
context.setState(new StandbyState());
}
}
public interface MusicPlayerContextInterface {
public void requestPlay();
public void setState(State state);
public State getState();
}
public class MusicPlayerContext implements MusicPlayerContextInterface {
State state;
public MusicPlayerContext(State state){
this.state = state;
}
@Override
public void requestPlay() {
state.pressPlay(this);
}
@Override
public void setState(State state) {
this.state = state;
}
@Override
public State getState() {
return state;
}
}
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21. 策略模式
21.1 UML类图
21.2 代码
public interface SortInterface { public void sort(int[] array);
}
public class QuickSort implements SortInterface {
@Override
public void sort(int[] array) {
// quick sort
System.out.println("Sort the arrat in quicksort");
}
}
public class BubbleSort implements SortInterface {
@Override
public void sort(int[] array) {
//bubble sort
System.out.println("Sort the arrat in bubblesort");
}
}
public abstract class Sorter {
private SortInterface strategy;
public void setSorter(SortInterface strategy){
this.strategy = strategy;
}
public SortInterface getSorter(){
return strategy;
}
public abstract void doSort(int[] listToSort);
}
public class MySorter extends Sorter {
@Override
public void doSort(int[] listToSort) {
getSorter().sort(listToSort);
}
}
public class StrategyTest {
public static void main(String[] args){
int[] listToSorted = {15,12,13,16,17};
MySorter mySorter = new MySorter();
mySorter.setSorter(new QuickSort());
mySorter.doSort(listToSorted);
mySorter.setSorter(new BubbleSort());
mySorter.doSort(listToSorted);
}
}
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21.3 策略枚举
它是一个枚举; 它是一个浓缩了的策略模式的枚举。
21.4 代码
public enum Calculator { ADD("+"){
@Override
public int exec(int a, int b) {
return a + b;
}
},
SUB("-"){
@Override
public int exec(int a, int b) {
return a - b;
}
};
private String symbol;
Calculator(String symbol){
this.symbol = symbol;
}
public abstract int exec(int a, int b);
}
public class Client {
public static void main(String[] args){
int a = 5, b=7;
System.out.println(Calculator.ADD.exec(a,b));
System.out.println(Calculator.SUB.exec(a,b));
}
}
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22. 模板方法模式
22.1 UML类图
22.2 代码
public abstract class Lunch { //模板方法
public final void prepareLunch(){
prepareIngredients();
cooking();
eating();
cleaning();
}
protected abstract void cleaning();
protected void eating(){
System.out.println("I am eating , please don't disturb me.");
}
protected abstract void cooking();
protected abstract void prepareIngredients();
}
public class McDonaldMeal extends Lunch {
@Override
public void cleaning() {
System.out.println("McDonald clean....");
}
@Override
public void cooking() {
System.out.println("McDonald cook....");
}
@Override
public void prepareIngredients() {
System.out.println("McDonald prepare..");
}
}
public class KFCMeal extends Lunch {
@Override
public void cleaning() {
System.out.println("KFC clean....");
}
@Override
public void cooking() {
System.out.println("KFC cook....");
}
@Override
public void prepareIngredients() {
System.out.println("KFC prepare....");
}
}
public class TemplateMethodTest {
public static void main(String[] args){
Lunch meal1 = new McDonaldMeal();
meal1.prepareLunch();
Lunch meal2 = new KFCMeal();
meal2.prepareLunch();
}
}
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23. 访问者模式
23.1 UML类图
23.2 代码
public abstract class Animal { public abstract void accept(Person person);
}
public class Cat extends Animal {
@Override
public void accept(Person person) {
person.feed(this);
System.out.println("喵喵喵");
}
}
public class Dog extends Animal {
@Override
public void accept(Person person) {
person.feed(this);
System.out.println("汪汪汪");
}
}
public abstract class Person {
public abstract void feed(Cat cat);
public abstract void feed(Dog dog);
}
public class Owner extends Person {
@Override
public void feed(Cat cat) {
System.out.println("主人喂食猫 喜欢");
}
@Override
public void feed(Dog dog) {
System.out.println("主人喂食狗 喜欢");
}
}
public class Someone extends Person {
@Override
public void feed(Cat cat) {
System.out.println("其他人喂食猫 警惕");
}
@Override
public void feed(Dog dog) {
System.out.println("其他人喂食狗 警惕");
}
}
public class Home {
private List<Animal> animals = new ArrayList<>();
public void addAnimal(Animal animal){
animals.add(animal);
}
public void action(Person person){
for (Animal anmial :
animals) {
anmial.accept(person);
}
}
}
public class VisitorTest {
public static void main(String[] args) {
Home owerHome = new Home();
owerHome.addAnimal(new Dog());
owerHome.addAnimal(new Cat());
Owner owner = new Owner();
owerHome.action(owner);
Someone someone = new Someone();
owerHome.action(someone);
}
}
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二、6大设计原则
● Single Responsibility Principle：单一职责原则
● Open Closed Principle：开闭原则
● Liskov Substitution Principle：里氏替换原则
● Law of Demeter：迪米特法则
● Interface Segregation Principle：接口隔离原则
● Dependence Inversion Principle：依赖倒置原则
三、拓展
3-1 动态代理模式
以上模式十一是静态代理。
JDK实现的动态代理, 被代理类必须实现一个接口(主要用到反射)；
public interface BookStore { public void addBook();
}
public class BookStoreImpl implements BookStore {
@Override
public void addBook() {
System.out.println("...add a book...");
}
}
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
/**
* @Author: rocky
* @Date: Created in 2018/5/7.
*/
public class BookStoreProxy implements InvocationHandler {
private Object target;
public BookStoreProxy(Object target){
this.target = target;
}
public Object getProxy() {
return Proxy.newProxyInstance(this.target.getClass().getClassLoader(),
this.target.getClass().getInterfaces(), this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("..jdk proxy start..");
Object result = method.invoke(target, args);
System.out.println("..jdk proxy end..");
return result;
}
public static void main(String[] args){
BookStore bookStore = (BookStore) new BookStoreProxy(new BookStoreImpl()).getProxy();
bookStore.addBook();
}
}
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CGLIB可以实现不需要接口也可以实现动态代理(原理是通过字节码技术为一个类创建子类，并在子类中采用方法拦截的技术拦截所有父类方法的调用)
public class SayHello { public void say(){
System.out.println("hello everyone");
}
}
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;
import java.lang.reflect.Method;
/**
* @Author: rocky
* @Date: Created in 2018/5/7.
*/
public class CglibProxy implements MethodInterceptor {
private Enhancer enhancer = new Enhancer();
public Object getProxy(Class clazz){
//设置需要创建子类的类
enhancer.setSuperclass(clazz);
enhancer.setCallback(this);
//通过字节码技术动态创建子类实例
return enhancer.create();
}
//实现接口MethodInterceptor接口方法
@Override
public Object intercept(Object o, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
System.out.println("insert before.....");
Object result = methodProxy.invokeSuper(o, args);
System.out.println("insert after.....");
return result;
}
public static void main(String[] args){
CglibProxy proxy = new CglibProxy();
SayHello sayHello = (SayHello) proxy.getProxy(SayHello.class);
sayHello.say();
}
}
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特别是调试时，只要看到类似$Proxy0这样的结构，你就应该知道这是一个动态代理了。
3-2 浅拷贝的注意事项
内部的数组和引用对象才不拷贝，其他的原始类型比如int、long、char等都会被拷贝，
但是对于String类型，Java就希望你把它认为是基本类型，它是没有clone方法的，
处理机制也比较特殊，通过字符串池（stringpool）在需要的时候才在内存中创建新的字符串，读者在使用的时候就把String当做基本类使用即可。
四、参考书籍
设计模式之禅（第2版）秦小波著
图解设计模式 [日] 结城浩
设计模式精解及面试攻略 [印] 纳拉西姆哈·卡鲁曼希
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