Java设计模式 - 责任链模式

电玩女神 2022-11-27 03:07 176阅读 0赞

**目录**

责任链模式：

责任链模式优点：

责任链模式应用：

责任链模式实例：

类图：

示例：

代码：

上述代码 GitHub 地址：https://github.com/baicun/designPatterns

--------------------

# [责任链模式：][Link 1] #

多个对象都有机会处理请求，为了避免请求发送者与接收者耦合在一起，将这些对象连接成一条链，并且沿着这条链传递请求，直到有对象处理它为止。职责链模式是一种对象行为型模式。

# [责任链模式][Link 1][优点：][Link 2] #

将请求的发送者和处理者解耦，使多个对象都有机会处理这个请求；

客户端调用简单，无需关心发送请求给谁，链结构怎样，调用简化；

可以动态的增加或删减处理请求的链结构

# [责任链模式应用：][Link 3] #

`Servlet` 过滤器

# [责任链模式][Link 1][实例：][Link 4] #

## [类图：][Link 5] ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NzZG5fMDkxMQ_size_16_color_FFFFFF_t_70][]

## [示例：][Link 6] ##

财务审批流程：财务人员计划购买一批货品，需要申请经费，于是他在OA系统上发起一笔经费请求（Client.java），不同经费额度分别有组长、部门经理、总经理审批，于是有了责任链设计模式。

## [代码：][Link 7] ##

客户端发起请求

//客户端发起请求
    public class Client {
    
    	public Client() { }
    
    	public PurchaseRequest sendRequst(int Type, int Number, float Price) {
    		return new PurchaseRequest(Type, Number, Price);
    	}
    
    }

具体处理者-组长

public class GroupApprover extends Approver {
    
    	public GroupApprover(String Name) {
    		super(Name+" GroupLeader");
    	}
    
    	@Override
    	public void ProcessRequest(PurchaseRequest request) {
    		if (request.GetSum() < 5000) {
    			System.out.println("**This request " + request.GetID()
    					+ " will be handled by "
    					+ this.Name + " **");
    		} else {
    			successor.ProcessRequest(request);
    		}
    	}
    
    }

具体处理者-部门经理

public class DepartmentApprover extends Approver {
    
    	public DepartmentApprover(String Name) {
    		super(Name + " DepartmentLeader");
    	}
    
    	@Override
    	public void ProcessRequest(PurchaseRequest request) {
    		if ((5000 <= request.GetSum()) && (request.GetSum() < 10000)) {
    			System.out.println("**This request " + request.GetID()
    					+ " will be handled by " + this.Name + " **");
    		} else {
    			successor.ProcessRequest(request);
    		}
    	}
    }

具体处理者-总经理

public class PresidentApprover extends Approver {
    
    	public PresidentApprover(String Name) {
    		super(Name + " President");
    	}
    
    	@Override
    	public void ProcessRequest(PurchaseRequest request) {
    		if (10000 <= request.GetSum()) {
    			System.out.println("**This request " + request.GetID()
    					+ " will be handled by " + this.Name + " **");
    		}else {
    			successor.ProcessRequest(request);
    		}
    	}
    }

测试类：

public class MainTest {
    
    	public static void main(String[] args) {
    		//初始化数据
    		Client mClient=new Client();
    		Approver GroupLeader=new GroupApprover("Tom");
    		Approver DepartmentLeader=new DepartmentApprover("Jerry");
    		Approver President=new PresidentApprover("Bush");
    
    		//设置责任链处理顺序
    		GroupLeader.SetSuccessor(DepartmentLeader);
    		DepartmentLeader.SetSuccessor(President);
    		President.SetSuccessor(GroupLeader);
    
    		//开始处理-设置处理起点：组长
    		GroupLeader.ProcessRequest(mClient.sendRequst(1, 100, 40));
    		GroupLeader.ProcessRequest(mClient.sendRequst(2, 200, 40));
    		GroupLeader.ProcessRequest(mClient.sendRequst(4, 400, 140));
    
    		//开始处理-设置处理起点：总经理
    		/*President.ProcessRequest(mClient.sendRequst(1, 100, 40));
    		President.ProcessRequest(mClient.sendRequst(2, 200, 40));
    		President.ProcessRequest(mClient.sendRequst(4, 400, 140));*/
    	}
    
    }

# [上述代码 GitHub 地址：https://github.com/baicun/designPatterns][GitHub _https_github.com_baicun_designPatterns] #

[Link 1]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%94%9F%E6%88%90%E5%99%A8%E6%A8%A1%E5%BC%8F%EF%BC%88%E5%BB%BA%E9%80%A0%E8%80%85%E6%A8%A1%E5%BC%8F%EF%BC%89%EF%BC%9A
[Link 2]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%94%9F%E6%88%90%E5%99%A8%E4%BC%98%E7%82%B9%EF%BC%9A
[Link 3]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%94%9F%E6%88%90%E5%99%A8%E6%A8%A1%E5%BC%8F%E5%BA%94%E7%94%A8%EF%BC%9A
[Link 4]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%94%9F%E6%88%90%E5%99%A8%E5%AE%9E%E4%BE%8B%EF%BC%9A
[Link 5]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%B1%BB%E5%9B%BE%EF%BC%9A
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NzZG5fMDkxMQ_size_16_color_FFFFFF_t_70]: /images/20221124/9711687345064d90815a6cb1b7c9fa19.png
[Link 6]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E7%A4%BA%E4%BE%8B%EF%BC%9A
[Link 7]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E4%BB%A3%E7%A0%81%EF%BC%9A
[GitHub _https_github.com_baicun_designPatterns]: https://blog.csdn.net/csdn_0911/article/details/107961992#%E4%B8%8A%E8%BF%B0%E4%BB%A3%E7%A0%81%20GitHub%20%E5%9C%B0%E5%9D%80%EF%BC%9Ahttps%3A%2F%2Fgithub.com%2Fbaicun%2FdesignPatterns