责任链模式：当客户提交请求时，请求会沿责任链传递，直至有一个对象负责处理它。当某个对象没有权限处理请求时，自动将处理转交上级

    优点：请求者不用管是哪个对象处理，最终请求一定会被处理

    实现：以普通员工申请请假和加薪为例，请假三天以内，经理处理；请假五天以内，加薪五百以内，总监处理；请假十天以内，加薪一千以内，大总监处理；请假超过十天，加薪超过一千，驳回申请
    1、请求类

    1. /**
    2.  * 请求类
    3.  */
    4. public class Request {
    5.     //请求方式
    6.     private String requestType;
    7.     //请求数量
    8.     private Integer requestNumber;
    10.     public String getRequestType() {
    11.         return requestType;
    12.     }
    14.     public void setRequestType(String requestType) {
    15.         this.requestType = requestType;
    16.     }
    18.     public Integer getRequestNumber() {
    19.         return requestNumber;
    20.     }
    22.     public void setRequestNumber(Integer requestNumber) {
    23.         this.requestNumber = requestNumber;
    24.     }
    25. }

    2、处理类

    1. /**
    2.  * 抽象管理者类
    3.  */
    4. public abstract class Manager {
    5.     //名称
    6.     String name;
    7.     //上级管理者
    8.     Manager superior;
    10.     public Manager(String name){
    11.         this.name = name;
    12.     }
    14.     /**
    15.      * 设置上级管理者
    16.      */
    17.     public abstract void setSuperior(Manager manager);
    19.     public abstract void handleRequest(Request request);
    20. }
    23. /**
    24.  * 经理
    25.  */
    26. public class CommonManager extends Manager{
    28.     public CommonManager(String name){
    29.         super(name);
    30.     }
    31.     /**
    32.      * 设置上级管理者
    33.      */
    34.     public void setSuperior(Manager manager){
    35.         super.superior = manager;
    36.     }
    38.     /**
    39.      * 有权限执行则执行，没有权限则向上提交
    40.      */
    41.     public void handleRequest(Request request){
    42.         if ("请假".equals(request.getRequestType()) && request.getRequestNumber() <= 3){
    43.             System.out.println(MessageFormat.format("{0}:通过申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    44.         }else{
    45.             System.out.println(MessageFormat.format("{0}:无权审批",name));
    46.             superior.handleRequest(request);
    47.         }
    48.     }
    49. }
    52. /**
    53.  * 总监
    54.  */
    55. public class Majordomo extends Manager{
    57.     public Majordomo(String name){
    58.         super(name);
    59.     }
    60.     /**
    61.      * 设置上级管理者
    62.      */
    63.     public void setSuperior(Manager manager){
    64.         super.superior = manager;
    65.     }
    67.     /**
    68.      * 有权限执行则执行，没有权限则向上提交
    69.      */
    70.     public void handleRequest(Request request){
    71.         if ("请假".equals(request.getRequestType()) && request.getRequestNumber() <= 5){
    72.             System.out.println(MessageFormat.format("{0}:通过申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    73.         }else if ("加薪".equals(request.getRequestType()) && request.getRequestNumber() <= 500){
    74.             System.out.println(MessageFormat.format("{0}:通过申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    75.         }else{
    76.             System.out.println(MessageFormat.format("{0}:无权审批",name));
    77.             superior.handleRequest(request);
    78.         }
    79.     }
    80. }
    83. /**
    84.  * 大总监
    85.  */
    86. public class GeneralManager extends Manager{
    88.     public GeneralManager(String name){
    89.         super(name);
    90.     }
    91.     /**
    92.      * 设置上级管理者
    93.      */
    94.     public void setSuperior(Manager manager){
    95.         super.superior = manager;
    96.     }
    98.     /**
    99.      * 有权限执行则执行，没有权限则驳回
    100.      */
    101.     public void handleRequest(Request request){
    102.         if ("请假".equals(request.getRequestType()) && request.getRequestNumber() <= 10){
    103.             System.out.println(MessageFormat.format("{0}:通过申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    104.         }else if ("加薪".equals(request.getRequestType()) && request.getRequestNumber() <= 1000){
    105.             System.out.println(MessageFormat.format("{0}:通过申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    106.         }else{
    107.             System.out.println(MessageFormat.format("{0}:驳回申请{1}，数量{2}" ,name , request.getRequestType() , request.getRequestNumber()));
    108.         }
    109.     }
    110. }

    3、测试类

    1. /**
    2.  * 测试责任链模式
    3.  */
    4. public class TestResponsibilityChain {
    5.     public static void main(String [] args){
    6.         Request request = new Request();
    7.         request.setRequestType("请假");
    8.         request.setRequestNumber(5);
    10.         Manager commonManager = new CommonManager("张三经理");
    11.         Manager majordomo = new Majordomo("李四总监");
    12.         Manager generalManager = new GeneralManager("王五大总监");
    14.         commonManager.setSuperior(majordomo);
    15.         majordomo.setSuperior(generalManager);
    16.         commonManager.handleRequest(request);
    17.     }
    18. }

    测试结果：
    image.png

    责任链模式是当系统中有大量分支判断时，需要用到的模式