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设计模式课程 设计模式精讲 12-3 适配器模式源码解析

时间:2019-09-14 11:34:40      阅读:127      评论:0      收藏:0      [点我收藏+]

标签:cut   error   解析   response   对象   ceo   pat   接口   exce   

1    源码解析

1.1  源码解析1(在jdk中的应用)

1.2  源码解析2(Spring中的通知管理)

1.3  源码解析3(SpringMVC中的应用)

 

 

1    源码解析

1.1  源码解析1(在jdk中的应用)

xmlAdapter(此类是用于适配xml的一个类,是处理xml序列化和反序列化的一个类)

public abstract class XmlAdapter<ValueType,BoundType> {

    /**
     * Do-nothing constructor for the derived classes.
     */
    protected XmlAdapter() {}

    /**
     *  处理反序列化*/
    public abstract BoundType unmarshal(ValueType v) throws Exception;

    /**
      * 处理序列化*/
    public abstract ValueType marshal(BoundType v) throws Exception;
}

 

对于xml序列化的时候,我们时间可以写一个date类,可以继承xmlAdapter抽象类,实现它的序列化和反序列化方法。

 

1.2  源码解析2(Spring中的通知管理)

功能描述:

通知适配器将通知类适配成各种类型的通知,如:前置通知,后置通知等等(关于通知的课程可以详细查看我的spring笔记)

 

通知适配器接口:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.aop.framework.adapter;

import org.aopalliance.aop.Advice;
import org.aopalliance.intercept.MethodInterceptor;
import org.springframework.aop.Advisor;

public interface AdvisorAdapter {
    boolean supportsAdvice(Advice var1);

    MethodInterceptor getInterceptor(Advisor var1);
}

 

前置通知适配器实现类:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.aop.framework.adapter;

import java.io.Serializable;
import org.aopalliance.aop.Advice;
import org.aopalliance.intercept.MethodInterceptor;
import org.springframework.aop.Advisor;
import org.springframework.aop.MethodBeforeAdvice;

class MethodBeforeAdviceAdapter implements AdvisorAdapter, Serializable {
    MethodBeforeAdviceAdapter() {
    }

    public boolean supportsAdvice(Advice advice) {
        return advice instanceof MethodBeforeAdvice;
    }

    public MethodInterceptor getInterceptor(Advisor advisor) {
        MethodBeforeAdvice advice = (MethodBeforeAdvice)advisor.getAdvice();
        return new MethodBeforeAdviceInterceptor(advice);
    }
}

 

advisor组合得到通知类:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.aop;

import org.aopalliance.aop.Advice;

public interface Advisor {
    Advice getAdvice();

    boolean isPerInstance();
}

 

MethodBeforeAdvice继承超类(隔了好几层继承实现):

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.aopalliance.intercept;

import org.aopalliance.aop.Advice;

public interface Interceptor extends Advice {
}

 

1.3  源码解析3(SpringMVC中的应用)

重点关注:

springmvc中,通过处理映射器(handlerMapper)找到对应的handler(controler,servlet或者httpRequestHandler)

现在是多个适配器,对应多个

 

适配器接口:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.web.servlet;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public interface HandlerAdapter {
    boolean supports(Object var1);

    ModelAndView handle(HttpServletRequest var1, HttpServletResponse var2, Object var3) throws Exception;

    long getLastModified(HttpServletRequest var1, Object var2);
}

 

适配器类:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.web.servlet.mvc;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.ModelAndView;

public class SimpleControllerHandlerAdapter implements HandlerAdapter {
    public SimpleControllerHandlerAdapter() {
    }

  /** 如果对应的handler有确切的Controller并支持的话,返回true,否则,返回false
   */
public boolean supports(Object handler) { return handler instanceof Controller; } public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { return ((Controller)handler).handleRequest(request, response); } public long getLastModified(HttpServletRequest request, Object handler) { return handler instanceof LastModified ? ((LastModified)handler).getLastModified(request) : -1L; } }

 

DispatcherServlet(通过handlermapper找到对应的handler,适配器中的client)

 protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
        HttpServletRequest processedRequest = request;
        HandlerExecutionChain mappedHandler = null;
        boolean multipartRequestParsed = false;
        WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);

        try {
            try {
                ModelAndView mv = null;
                Exception dispatchException = null;

                try {
                    processedRequest = this.checkMultipart(request);
                    multipartRequestParsed = processedRequest != request;
                    mappedHandler = this.getHandler(processedRequest);
                    if (mappedHandler == null || mappedHandler.getHandler() == null) {
                        this.noHandlerFound(processedRequest, response);
                        return;
                    }

                    HandlerAdapter ha = this.getHandlerAdapter(mappedHandler.getHandler());
                    String method = request.getMethod();
                    boolean isGet = "GET".equals(method);
                    if (isGet || "HEAD".equals(method)) {
                        long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
                        if (this.logger.isDebugEnabled()) {
                            this.logger.debug("Last-Modified value for [" + getRequestUri(request) + "] is: " + lastModified);
                        }

                        if ((new ServletWebRequest(request, response)).checkNotModified(lastModified) && isGet) {
                            return;
                        }
                    }

                    if (!mappedHandler.applyPreHandle(processedRequest, response)) {
                        return;
                    }

                    try {
            //通过适配器handle方法,返回对应的model&View对象 mv
= ha.handle(processedRequest, response, mappedHandler.getHandler()); } finally { if (asyncManager.isConcurrentHandlingStarted()) { return; } } this.applyDefaultViewName(request, mv); mappedHandler.applyPostHandle(processedRequest, response, mv); } catch (Exception var27) { dispatchException = var27; } this.processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException); } catch (Exception var28) { this.triggerAfterCompletion(processedRequest, response, mappedHandler, var28); } catch (Error var29) { this.triggerAfterCompletionWithError(processedRequest, response, mappedHandler, var29); } } finally { if (asyncManager.isConcurrentHandlingStarted()) { mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response); return; } else { if (multipartRequestParsed) { this.cleanupMultipart(processedRequest); } } } }

 

controller接口:

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.web.servlet.mvc;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;

public interface Controller {
    ModelAndView handleRequest(HttpServletRequest var1, HttpServletResponse var2) throws Exception;
}

 

设计模式课程 设计模式精讲 12-3 适配器模式源码解析

标签:cut   error   解析   response   对象   ceo   pat   接口   exce   

原文地址:https://www.cnblogs.com/1446358788-qq/p/11518244.html

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