Spring----工厂注入和bean的生命周期

Z时代
2024-01-10
分类：综合

本文内容纲要：

- 独立的集合bean - P名空间 - 静态工厂注入 - 实例工厂注入 - bean之间的依赖关系 - 生命周期" title="bean的生命周期">bean的生命周期 - 使用注解配置：

独立的集合bean

在多个bean之间可共享该独立bean。

示例：

<bean id="car1" class="com.entity.Car">
        <property name="brand" value="BMW"/>
        <property name="color" value="白色"/>
    </bean>
    <bean id="car2" class="com.entity.Car">
        <property name="brand" value="BENZ"/>
        <property name="color" value="红色"/>
    </bean>
    <bean id="car3" class="com.entity.Car">
        <property name="brand" value="AUDI"/>
        <property name="color" value="黑色"/>
    </bean>
<util:list id="mycars">
        <ref bean="car1"/>
        <ref bean="car2"/>
        <ref bean="car3"/>
    </util:list>

在其他bean中即可共享该mycars--bean。

<bean name="stu,s1,s2" class="com.entity.Students">
        <property name="cars">
            <ref bean="mycars"/>
        </property>
    </bean>

P名空间

使用p命名空间时需要先声明使用对应的命名空间，即在beans元素上加入：

xmlns:p="http://www.springframework.org/schema/p"

使用p命名空间的好处是简化配置信息。

示例：

<bean id="car1" class="com.entity.Car" p:brand="BMW" p:color="白色"/>
    <bean id="car2" class="com.entity.Car" p:brand="BENZ" p:color="红色"/>
    <bean id="car3" class="com.entity.Car" p:brand="AUDI" p:color="黑色"/>

静态工厂注入

使用的是工厂中的静态方法。

在service层引用的dao，1.可以使用原始的方式注入，2.也可以使用静态工厂注入，自己编写一个工厂类，里面静态方法返回一个dao的实现类对象。

静态工厂BinessDAOFactory：

package com.factory;
import com.dao.CarDAO;
import com.dao.StudentsDAO;
import com.dao.impl.CarDAOImpl;
import com.dao.impl.StudentsDAOImpl;
public class BinessDAOFactory {
    //获得学生的DAO实例
    public static StudentsDAO getStudentsDAOImplInstance(){
        return new StudentsDAOImpl();
    }
    //获得汽车的DAO实例、
    public static CarDAO getCarDAOImplInstance(){
        return new CarDAOImpl();
    }
    //获得用户的DAO实例
    /*public static UsersDAO getUsersDAOImplInstance(){
        return new UsersDAOImpl();
    }*/
}

applicationContext.xml：

<!-- 一个学生bean -->
    <bean id="s" class="com.entity.Students" p:sid="s0001" p:name="金泰妍" p:gender="女" p:birthday="1989-03-09" p:address="韩国"/>
     <!-- 学生dao bean -->
     <bean id="sDao" class="com.factory.BinessDAOFactory" 
         factory-method="getStudentsDAOImplInstance">//静态方法
     </bean>
      <!-- 学生service bean -->
     <bean id="sService" class="com.service.impl.StudentsServiceImpl">
         <property name="studentsDAO" ref="sDao"></property>
     </bean>

测试：

@Test
    public void fun1(){
        ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        Students s=(Students) ctx.getBean("s");
        //System.out.println(s);
        StudentsServiceImpl sService=(StudentsServiceImpl) ctx.getBean("sService");
        sService.add(s);
    }

实例工厂注入

工厂：

public class BinessDAOFactory {
    //获得学生的DAO实例
    public StudentsDAO getStudentsDAOImplInstance(){
        return new StudentsDAOImpl();
    }
}

applicationContext.xml：

<!-- 工厂bean的注入 -->
     <bean id="businessFactory" class="com.factory.BinessDAOFactory"></bean>
     <!-- 实例工厂注入--得到dao的bean -->
      <bean id="sDao1" factory-bean="businessFactory" factory-method="getStudentsDAOImplInstance">
      </bean>
      <!-- 学生service bean -->
     <bean id="sService" class="com.service.impl.StudentsServiceImpl">
         <property name="studentsDAO" ref="sDao1"></property>
     </bean>

测试：

public class StudentServiceImplTest {
    @Test
    public void fun1(){
        ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        Students s=(Students) ctx.getBean("s");
        //System.out.println(s);
        StudentsServiceImpl sService=(StudentsServiceImpl) ctx.getBean("sService");
        sService.add(s);
    }
}

bean之间的依赖关系

在Students类中加上Car car这个属性字段。

<!-- 一个学生bean -->
    <bean id="s" class="com.entity.Students" p:sid="s0001" p:name="金泰妍" p:gender="女" p:birthday="1989-03-09" p:address="韩国" p:car-ref="c" depends-on="c"/>
    <bean id="c" class="com.entity.Car" p:brand="BWM" p:color="白色"/>

学生bean依赖汽车bean，在初始化的时候会先初始化Car。

bean的生命周期

1.懒加载，在用到该bean的时候，才会去初始化它，加载它。

Students.java：

package com.entity;
import java.io.Serializable;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
//加注解注入，起一个别名s1
@Component("haha")
public class Students implements Serializable {
    private String sid;// 学号
    private String name;// 姓名
    private String gender;// 性别
    private Date birthday;// 生日
    private String address;// 住址
    private Car car;// 学生拥有的车的引用
//    private List<Car> cars;
    //初始化方法，在构造方法之后调用
    public void initStudents(){
        System.out.println("执行学生的initStudents()方法");
    }
    //在ApplicationContext对象被销毁的时候执行
    public void destroyStudents(){
        System.out.println("执行学生的destroyStudents()方法");
    }
    public Students(String sid, String name, String gender, Date birthday,
            String address) {
        super();
        this.sid = sid;
        this.name = name;
        this.gender = gender;
        this.birthday = birthday;
        this.address = address;
    }
    public Students(String sid, String name, String gender, Date birthday,
        String address, Car car) {
    super();
    this.sid = sid;
    this.name = name;
    this.gender = gender;
    this.birthday = birthday;
    this.address = address;
    this.car = car;
    }
    public Car getCar() {
        return car;
    }
    public void setCar(Car car) {
        this.car = car;
    }
    public Students(String sid, String name, String gender, String address) {
        this.sid = sid;
        this.name = name;
        this.gender = gender;
        this.address = address;
    }
    /*//解决方法1:
    //在构造方法之后执行一些初始化的操作
    @PostConstruct
    public void init(){
        //在调用完构造函数之后，birthday还为null，然后使用这个直接赋值
        try {
            this.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("2000-05-17"));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }*/
    public Students() {
        System.out.println("一个学生创建啦...");
    }
    public String getSid() {
        return sid;
    }
//    @Value("s0006")
    public void setSid(String sid) {
        this.sid = sid;
    }
    public String getName() {
        return name;
    }
//    @Value("IU")
    public void setName(String name) {
        System.out.println("执行了setName()方法");
        this.name = name;
    }
    public String getGender() {
        return gender;
    }
//    @Value("女")
    public void setGender(String gender) {
        this.gender = gender;
    }
    public Date getBirthday() {
        return birthday;
    }
//    @Value("1998-07-15")
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
//    @Value("韩国首尔")
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "Students [sid=" + sid + ", name=" + name + ", gender=" + gender
                + ", birthday=" + birthday + ", address=" + address + ", car="
                + car + "]";
    }
}

applicationContext.xml：

<!-- 一个学生bean -->
    <bean id="s" class="com.entity.Students" p:sid="s0001" p:name="金泰妍" p:gender="女" p:birthday="1989-03-09" p:address="韩国" p:car-ref="c" depends-on="c" lazy-init="true" init-method="initStudents" destroy-method="destroyStudents" scope="prototype"/>
    <bean id="c" class="com.entity.Car" p:brand="BWM" p:color="白色"/>

测试：

public class StudentServiceImplTest {
    @Test
    public void fun1(){
        ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        Students s=(Students) ctx.getBean("s");
        Students ss=(Students) ctx.getBean("s");
        System.out.println(s==ss);//单例：true prototype：false
        //System.out.println(s);
        StudentsServiceImpl sService=(StudentsServiceImpl) ctx.getBean("sService");
        sService.add(s);
        ((ClassPathXmlApplicationContext)ctx).close();
    }
}

使用注解配置：

Students.java：

package com.entity;
import java.io.Serializable;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.DependsOn;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
//加注解注入，起一个别名s1
@Component("s")
@DependsOn(value="car")//依赖关系
@Scope("prototype")//得到的bean对象是否为单例的singleton,prototype
public class Students implements Serializable {
    private String sid;// 学号
    private String name;// 姓名
    private String gender;// 性别
    private Date birthday;// 生日
    private String address;// 住址
    private Car car;// 学生拥有的车的引用
//    private List<Car> cars;
    //初始化方法，在构造方法之后调用
    @PostConstruct//初始化方法
    public void initStudents(){
        System.out.println("执行学生的initStudents()方法");
    }
    //在ApplicationContext对象被销毁的时候执行
    @PreDestroy//销毁方法
    public void destroyStudents(){
        System.out.println("执行学生的destroyStudents()方法");
    }
    public Students(String sid, String name, String gender, Date birthday,
            String address) {
        super();
        this.sid = sid;
        this.name = name;
        this.gender = gender;
        this.birthday = birthday;
        this.address = address;
    }
    public Students(String sid, String name, String gender, Date birthday,
        String address, Car car) {
    super();
    this.sid = sid;
    this.name = name;
    this.gender = gender;
    this.birthday = birthday;
    this.address = address;
    this.car = car;
    }
    public Car getCar() {
        return car;
    }
    @Resource(name="car")
    public void setCar(Car car) {
        this.car = car;
    }
    public Students(String sid, String name, String gender, String address) {
        this.sid = sid;
        this.name = name;
        this.gender = gender;
        this.address = address;
    }
    /*//解决方法1:
    //在构造方法之后执行一些初始化的操作
    @PostConstruct
    public void init(){
        //在调用完构造函数之后，birthday还为null，然后使用这个直接赋值
        try {
            this.setBirthday(new SimpleDateFormat("yyyy-MM-dd").parse("2000-05-17"));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }*/
    public Students() {
        System.out.println("一个学生创建啦...");
    }
    public String getSid() {
        return sid;
    }
    @Value("s0006")
    public void setSid(String sid) {
        this.sid = sid;
    }
    public String getName() {
        return name;
    }
    @Value("IU")
    public void setName(String name) {
        System.out.println("执行了setName()方法");
        this.name = name;
    }
    public String getGender() {
        return gender;
    }
    @Value("女")
    public void setGender(String gender) {
        this.gender = gender;
    }
    public Date getBirthday() {
        return birthday;
    }
    @Value("1998-07-15")
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
    @Value("韩国首尔")
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "Students [sid=" + sid + ", name=" + name + ", gender=" + gender
                + ", birthday=" + birthday + ", address=" + address + ", car="
                + car + "]";
    }
}

Car.java：

package com.entity;
import java.io.Serializable;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
//注解注入，，之后的实例名称叫car
@Component("car")
public class Car implements Serializable{
    private String brand;// 品牌
    private String color;// 颜色
    public Car() {
        System.out.println("一辆汽车诞生啦...");
    }
    public Car(String brand, String color) {
        super();
        this.brand = brand;
        this.color = color;
    }
    public String getBrand() {
        return brand;
    }
    @Value("BMW")
    public void setBrand(String brand) {
        this.brand = brand;
    }
    public String getColor() {
        return color;
    }
    @Value("黑色")
    public void setColor(String color) {
        this.color = color;
    }
    @Override
    public String toString() {
        return "Car [brand=" + brand + ", color=" + color + "]";
    }
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util"
    xmlns:cache="http://www.springframework.org/schema/cache"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
                      http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
                      http://www.springframework.org/schema/aop
                      http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
                      http://www.springframework.org/schema/util
                      http://www.springframework.org/schema/util/spring-util-4.0.xsd
                      http://www.springframework.org/schema/context
                      http://www.springframework.org/schema/context/spring-context-4.0.xsd
                      http://www.springframework.org/schema/tx 
                      http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
                      http://www.springframework.org/schema/cache 
                      http://www.springframework.org/schema/cache/spring-cache-4.0.xsd">
    <!-- 表示使用注解 -->
    <context:annotation-config/>
    <!-- 扫描带注解的包 -->
    <context:component-scan base-package="com.entity"/>
    <!-- 实现类型转换的bean -->
    <!-- id的名字必须是这个 -->
    <bean id="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
        <property name="propertyEditorRegistrars">
            <list>
                <bean class="com.convert.MyCustomDateEditorRegister">
                    <property name="format" value="yyyy-MM-dd"></property>
                </bean>
            </list>
        </property>
    </bean>
    <bean id="dateFormat" class="java.text.SimpleDateFormat">
        <constructor-arg value="yyyy-MM-dd"/>
    </bean>
    <!-- 一个学生bean -->
    <!-- <bean id="s" class="com.entity.Students" p:sid="s0001" p:name="金泰妍" p:gender="女" p:birthday="1989-03-09" p:address="韩国" p:car-ref="c" depends-on="c" lazy-init="true" init-method="initStudents" destroy-method="destroyStudents" scope="prototype"/>
    <bean id="c" class="com.entity.Car" p:brand="BWM" p:color="白色"/> -->
     <!-- 静态工厂注入 学生dao bean -->
     <!-- <bean id="sDao" class="com.factory.BinessDAOFactory" 
         factory-method="getStudentsDAOImplInstance">
     </bean> -->
     <!-- 工厂bean的注入 -->
     <bean id="businessFactory" class="com.factory.BinessDAOFactory"></bean>
     <!-- 实例工厂注入##得到dao的bean -->
      <bean id="sDao1" factory-bean="businessFactory" factory-method="getStudentsDAOImplInstance">
      </bean>
      <!-- 学生service bean -->
     <bean id="sService" class="com.service.impl.StudentsServiceImpl">
         <property name="studentsDAO" ref="sDao1"></property>
     </bean>
</beans>

测试：

package com.service.impl;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.entity.Students;
public class StudentServiceImplTest {
    @Test
    public void fun1(){
        ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        Students s=(Students) ctx.getBean("s");
        Students ss=(Students) ctx.getBean("s");
        System.out.println(s==ss);//单例：true prototype：false
        //System.out.println(s);
        StudentsServiceImpl sService=(StudentsServiceImpl) ctx.getBean("sService");
        sService.add(s);
        ((ClassPathXmlApplicationContext)ctx).close();
    }
}