责任链模式案例

需求背景：

请你设计一个员工休假审批流程，当员工的休假天数<=1时，由直接领导审批，休假天数<=2时，分别由直接领导、一级部门领导审批，休假天数>=3时，分别由直接领导、一级部门领导、分管领导审批。

不使用责任链：

package com.shejimoshi;public class Main {public static void main(String[] args) {RequestParam requestParam = new RequestParam("MJ", 3);if (requestParam.getTime()>=1){System.out.println("领导审批");if (requestParam.getTime()>=2){System.out.println("一级部门领导审批");if (requestParam.getTime()>=3){System.out.println("分管领导审批");}}}}
}

使用责任链各司其职：

抽象审批类AuditHandler,包含下一个处理者的引用nextAuditHandler,通过setNextAuditHandler方法进行注入,从而形成一条链，抽象audit方法，由各个处理者的实现类去实现各自的审批逻辑。

package com.shejimoshi;public abstract class AuditHandler {protected AuditHandler nextAuditHandler;public void setNextAuditHandler(AuditHandler nextAuditHandler) {this.nextAuditHandler = nextAuditHandler;}public abstract void audit(RequestParam requestParam);
}
class DirectLeaderAuditHandler extends AuditHandler{@Overridepublic void audit(RequestParam requestParam) {if (requestParam.getTime()>=1){System.out.println("班主任审批通过");}if (nextAuditHandler != null){nextAuditHandler.audit(requestParam);}else {System.out.println("审批完成");}}
}
class FirstLeaderAuditHandler extends AuditHandler{@Overridepublic void audit(RequestParam requestParam) {if (requestParam.getTime()>=2){System.out.println("学院审批通过");}if (nextAuditHandler != null){nextAuditHandler.audit(requestParam);}else {System.out.println("审批完成");}}
}
class FenGuanLeaderAuditHandler extends AuditHandler{@Overridepublic void audit(RequestParam requestParam) {if (requestParam.getTime()>=3){System.out.println("学校审批通过");}if (nextAuditHandler != null){nextAuditHandler.audit(requestParam);}else {System.out.println("审批完成");}}
}
class Test{public static void main(String[] args) {AuditHandler handler = new DirectLeaderAuditHandler();FirstLeaderAuditHandler firstLeaderAuditHandler = new FirstLeaderAuditHandler();FenGuanLeaderAuditHandler fenGuanLeaderAuditHandler = new FenGuanLeaderAuditHandler();handler.setNextAuditHandler(firstLeaderAuditHandler);firstLeaderAuditHandler.setNextAuditHandler(fenGuanLeaderAuditHandler);RequestParam requestParam = new RequestParam("MJ", 2);handler.audit(requestParam);}
}

摘取：

面试官：什么是责任链模式？_说一说责任链模式面试-CSDN博客