Java设计模式之职责链模式详解

目录

• 前言
• 一、职责链模式的定义与特点
• 二、职责链模式的结构
• 三、职责链模式案例

package com.chainOfResponsibilityPattern.SubmitAccount;
/**
 * @author wang
 * @version 1.0
 * @packageName com.chainOfResponsibilityPattern.SubmitAccount
 * @className PurchaseRequest
 * @date 2021/12/28 19:31
 * @Descriptio 该类为请求对象，封装了请求处理的相关信息
 * 变量分别为请求类型，编号，价格
 */
public class PurchaseRequest {
    private String type;
    private int id;
    private float price;
    public PurchaseRequest(String type, int id, float price) {
        this.type = type;
        this.id = id;
        this.price = price;
    }
    public String getType() {
        return type;
    }
    public int getId() {
        return id;
    }
    public float getPrice() {
        return price;
    }
}

package com.chainOfResponsibilityPattern.SubmitAccount;
/**
 * @author wang
 * @version 1.0
 * @packageName com.chainOfResponsibilityPattern.SubmitAccount
 * @className ApprovePeople
 * @date 2021/12/28 19:36
 * @Description 处理审批人的类，抽象处理请求的类
 */
public abstract class ApprovePeople {
    /**
     * 下一个审批人
     */
    ApprovePeople approvePeople;
    /**
     * 审批人名称
     */
    String name;
    public ApprovePeople(String name) {
        this.name = name;
    }
    /**
     * @param approvePeople
     * @Date 2021/12/28 19:39
     * @Param
     * @Return void
     * @MetodName setNext
     * @Author wang
     * @Description 设置下一个审批人的对象
     */
    public void setNext(ApprovePeople approvePeople) {
        this.approvePeople = approvePeople;
    }
    /**
     * @param purchaseRequest
     * @Date 2021/12/28 19:40
     * @Param
     * @Return void
     * @MetodName handleRequest
     * @Author wang
     * @Description 处理请求的方法，由该类的子类根据自己的情况去实现
     */
    public abstract void handleRequest(PurchaseRequest purchaseRequest);
}

package com.chainOfResponsibilityPattern.SubmitAccount;
/**
 * @author wang
 * @version 1.0
 * @packageName com.chainOfResponsibilityPattern.SubmitAccount
 * @className TeacherDirector
 * @date 2021/12/28 19:47
 * @Description 教学主任类，具体的处理请求的类
 */
public class TeacherDirector extends ApprovePeople {
    public TeacherDirector(String name) {
        super(name);
    }
    @Override
    public void handleRequest(PurchaseRequest purchaseRequest) {
        if (purchaseRequest.getPrice() <= 5000) {
            System.out.println("请求编号为：" + purchaseRequest.getId() + "\n请求类型为：" + purchaseRequest.getType() +
                    "\n请求金额为：" + purchaseRequest.getPrice() + "的项目被" + this.name + "处理成功");
        } else {
            approvePeople.handleRequest(purchaseRequest);
        }
    }
}

package com.chainOfResponsibilityPattern.SubmitAccount;
/**
 * @author wang
 * @version 1.0
 * @packageName com.chainOfResponsibilityPattern.SubmitAccount
 * @className DeanApprove
 * @date 2021/12/28 19:52
 * @Description 院长处理类，具体的处理请求的类
 */
public class DeanApprove extends ApprovePeople{
    public DeanApprove(String name) {
        super(name);
    }
    @Override
    public void handleRequest(PurchaseRequest purchaseRequest) {
        if(purchaseRequest.getPrice()> 5000 && purchaseRequest.getPrice() <= 10000) {
            System.out.println("请求编号为：" + purchaseRequest.getId() + "\n请求类型为：" + purchaseRequest.getType() +
                    "\n请求金额为：" + purchaseRequest.getPrice() + "的项目被" +this.name +"处理成功");
        }else {
            approvePeople.handleRequest(purchaseRequest);
        }
    }
}

package com.chainOfResponsibilityPattern.SubmitAccount;
/**
 * @author wang
 * @version 1.0
 * @packageName com.chainOfResponsibilityPattern.SubmitAccount
 * @className ClientTest
 * @date 2021/12/28 19:58
 * @Description 客户测试类
 */
public class ClientTest {
    public static void main(String[] args) {
        //创建一个请求
        PurchaseRequest purchaseRequest = new PurchaseRequest("体育用品", 1, 4000);
        //创建相关审批人
        TeacherDirector zhang1 = new TeacherDirector("张主任");
        DeanApprove li2 = new DeanApprove("李院长");
        VicePresident chen3 = new VicePresident("陈副院长");
        President liu4 = new President("刘校长");
        /**
         * 切记一定要让个处理者之间连接起来，否则会报出空指针异常,且需要构成一个环
         *
         */
        zhang1.setNext(li2);
        li2.setNext(chen3);
        chen3.setNext(liu4);
        liu4.setNext(zhang1);
        //处理请求
        zhang1.handleRequest(purchaseRequest);
    }
}