java之责任链模式

一、简介

责任链模式（Chain of Responsibility Pattern）是一种行为设计模式，它允许多个对象有机会处理一个请求。请求沿着处理者链传递，直到某个处理者决定处理此请求。

二、技术实现

2.1 Handler

public interface Handler{
    void handle(Request req, Response resp, Chain chain);
}

2.2 Chain

public class Chain{
   
    private List<Handler> handlers;
    
    private int index;

    public Chain(List<Handler> handlers){

         this.handlers = handlers;

    }

   
    public void next(Request req, Response resp){
        
        if (index + 1 < handlers.size()){

            handlers.get(index++).handle(req, resp, this);
         
        }

    }
}

2.3 Handler 实现

public LogHandler implements Handler{

    @Override
    public void Handle (Request req, Response resp, Chain chain){
        long start = System.currentTimeStamps();
        chain.next(req,resp);
        log.info("request:{},response:{}, duration:{}",req, resp, System.currentTimeStamps() - start);         
    }
}