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{@Overridepublic 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);         }
}