springMVC教程初级(二)初始springmvc（详细分析）
一、前言
前一章节对springMVC初步讲解了，我们得知它由C-Dispatcher；M-HanlderMapping、HandlerAdapter、Handler；V-ViewResolver三部分组成；其中我们加入了一个spring的字符集拦截器CharacterEncodingFilter在我们的Web.xml里面，构成为SpringMVC。我们只有记住spring的这几个大结构，即使其中的某个部分换了组件，依然能够知道怎么去配置，例如struts2的整合。接下来首先讲一下映射器HandlerMapping与HandlerAdapter。
二、非注解处理器映射器与适配器
2.1 BeanNameUrlHandlerMapping与SimpleUrlHanlderMapping映射器
2.1.1 BeanNameUrlHandlerMapping
匹配Spring容器Bean的Name找到的Bean（程序员编写Hanlder）
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" /> <!-- 2.1 BeanNameUrlHandlerMapping controller配置 --> <bean name="/items1" id="itemList1" class="com.ycy.controller.ItemController"/>
2.1.2 SimpleUrlHandlerMapping
BeanNameHandlerMapping的升级版，因为它可以统一配置Controller里面对应Url
<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping" >
<property name="mappings">
<props>
<prop key="/simpleItems1" >simpleController1</prop>
<prop key="/simpleItems2" >simpleController1</prop>
</props>
</property>
</bean>
<bean id="simpleController1" class="com.ycy.controller.ItemController"/>注意：benaname与simple两者同时配置，那么两者同时有效。
2.2 SimpleControllerHandlerAdapter与HttpRequestHandlerAdapter适配器
2.2.1 SimpleControllerHandlerAdapter
<bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter">
</bean>
要求程序编写的Handler(Controller)需要实现 Controller接口。
package com.ycy.controller;
import com.ycy.model.Items;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by Administrator on 2015/9/17 0017.
*/
public class ItemController implements Controller {
public ModelAndView handleRequest(javax.servlet.http.HttpServletRequest httpServletRequest,
javax.servlet.http.HttpServletResponse httpServletResponse) throws Exception {
//商品列表
List<Items> itemsList = new ArrayList<Items>();
Items items_1 = new Items();
items_1.setName("联想笔记本");
items_1.setPrice(6000f);
items_1.setDetail("ThinkPad T430 联想笔记本电脑！");
items_1.setCreatetime(new Date());
Items items_2 = new Items();
items_2.setName("苹果手机");
items_2.setPrice(5000f);
items_2.setDetail("iphone6苹果手机！");
items_2.setCreatetime(new Date());
itemsList.add(items_1);
itemsList.add(items_2);
//创建modelAndView准备填充数据、设置视图
ModelAndView modelAndView = new ModelAndView();
httpServletRequest.setCharacterEncoding("utf-8");
//填充数据
modelAndView.addObject("itemsList", itemsList);
//视图
modelAndView.setViewName("order/itemsList");
return modelAndView;
}
}
2.2.2 HttpRequestHandlerAdapter
要求Handler 实现 HttpRequestHandler接口
<bean class="org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter">
</bean>提醒：我用的时候需要加全路径
package com.ycy.controller;
import com.ycy.model.Items;
import org.springframework.web.HttpRequestHandler;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by Administrator on 2015/9/17 0017.
*/
public class ItemController2 implements HttpRequestHandler {
@Override
public void handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException {
//商品列表
List<Items> itemsList = new ArrayList<Items>();
Items items_1 = new Items();
items_1.setName("联想笔记本");
items_1.setPrice(6000f);
items_1.setDetail("ThinkPad T430 联想笔记本电脑！");
items_1.setCreatetime(new Date());
Items items_2 = new Items();
items_2.setName("苹果手机");
items_2.setPrice(5000f);
items_2.setDetail("iphone6苹果手机！");
items_2.setCreatetime(new Date());
itemsList.add(items_1);
itemsList.add(items_2);
//创建modelAndView准备填充数据、设置视图
ModelAndView modelAndView = new ModelAndView();
httpServletRequest.setCharacterEncoding("utf-8");
httpServletRequest.setAttribute("itemsList", itemsList);
httpServletRequest.getRequestDispatcher("pages/jsp/order/itemsList.jsp").forward(httpServletRequest,httpServletResponse);
}
}
三、注解处理器映射器与适配器
3.1注解映射器
spring3.1版本之前加载映射器org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping
spring3.1之后用org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping
也是源码解读：/org/springframework/spring-webmvc/4.2.0.RELEASE/spring-webmvc-4.2.0.RELEASE.jar!/org/springframework/web/servlet/DispatcherServlet.properties里面清楚记载了先加载谁
在springmvc.xml中配置RequestMappingHandlerMapping：
使用RequestMappingHandlerMapping需要在Handler 中使用@controller标识此类是一个控制器，使用@requestMapping指定Handler方法所对应的url。
<!--
2.3使用注解RequestMappingInfoHandlerMapping映射器
注解映射器配对使用，主要解析Handler方法中的形参
单个：
<bean class="com.ycy.controller.ItemController3"/>
-->
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping">
</bean>
<context:component-scan base-package="com.ycy.controller"/>
3.2注解适配器
spring3.1版本之前org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter
spring3.1版本之后org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter
<!--
3.3 RequestMappingHandlerAdapter：注解适配器，与RequestMappingInfoHandlerMapping配对使用
-->
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>
3.3Controler
package com.ycy.controller;
import com.ycy.model.Items;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by Administrator on 2015/9/17 0017.
*/
@Controller
public class ItemController3 {
@RequestMapping("/queryItems")//建议与方法名称一致
public ModelAndView queryItems(javax.servlet.http.HttpServletRequest httpServletRequest,
javax.servlet.http.HttpServletResponse httpServletResponse) throws Exception {
//商品列表
List<Items> itemsList = new ArrayList<Items>();
Items items_1 = new Items();
items_1.setName("联想笔记本");
items_1.setPrice(6000f);
items_1.setDetail("ThinkPad T430 联想笔记本电脑！");
items_1.setCreatetime(new Date());
Items items_2 = new Items();
items_2.setName("苹果手机");
items_2.setPrice(5000f);
items_2.setDetail("iphone6苹果手机！");
items_2.setCreatetime(new Date());
itemsList.add(items_1);
itemsList.add(items_2);
//创建modelAndView准备填充数据、设置视图
ModelAndView modelAndView = new ModelAndView();
httpServletRequest.setCharacterEncoding("utf-8");
//填充数据
modelAndView.addObject("itemsList", itemsList);
//视图
modelAndView.setViewName("order/itemsList");
return modelAndView;
}
}
四、SpringMVC总结分析
前面我们清楚了一下流程，现在我们看看spring源码分析，到底这些流程是怎么来的。DispatcherServlet：前端控制器，中央指挥机器，降低组件之间的耦合度。HandlerMappring: 负责处理器映射，根据url找到HandleHandlerAdapter：处理器适配器，根据处理器需求执行适配器。可以通过扩展适配器支持不同类型的Handler 例如：Struts2ViewResolver：视图解析器，根据逻辑视图解析为真正的视图。视图地址=前缀+逻辑视图名+后缀视图解析器配置：<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/pages/jsp/"/> <property name="suffix" value=".jsp"/> </bean>执行流程：1、DispatcherServlet我们进入该类看到doDispatch这个方法有个注释：
Process the actual dispatching to the handler 翻译：进程调度的实际处理程序。这个就是我们的中心处理程序方法：
protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception { HttpServletRequest processedRequest = request; HandlerExecutionChain mappedHandler = null; boolean multipartRequestParsed = false; WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request); try { ModelAndView mv = null; Exception dispatchException = null; try { processedRequest = checkMultipart(request); multipartRequestParsed = (processedRequest != request); // Determine handler for the current request. mappedHandler = getHandler(processedRequest); if (mappedHandler == null || mappedHandler.getHandler() == null) { noHandlerFound(processedRequest, response); return; } // Determine handler adapter for the current request. HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler()); // Process last-modified header, if supported by the handler. String method = request.getMethod(); boolean isGet = "GET".equals(method); if (isGet || "HEAD".equals(method)) { long lastModified = ha.getLastModified(request, mappedHandler.getHandler()); if (logger.isDebugEnabled()) { 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; } // Actually invoke the handler. mv = ha.handle(processedRequest, response, mappedHandler.getHandler()); if (asyncManager.isConcurrentHandlingStarted()) { return; } applyDefaultViewName(processedRequest, mv); mappedHandler.applyPostHandle(processedRequest, response, mv); } catch (Exception ex) { dispatchException = ex; } processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException); } catch (Exception ex) { triggerAfterCompletion(processedRequest, response, mappedHandler, ex); } catch (Error err) { triggerAfterCompletionWithError(processedRequest, response, mappedHandler, err); } finally { if (asyncManager.isConcurrentHandlingStarted()) { // Instead of postHandle and afterCompletion if (mappedHandler != null) { mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response); } } else { // Clean up any resources used by a multipart request. if (multipartRequestParsed) { cleanupMultipart(processedRequest); } } } }1】 Dispatcher通过Hander查询handle
2】Dispatcher 通过适配器执行Handler，得到ModelAndView3】得到ModelAndView，解析视图
解析视图最里层我们看看。再往里，其实就是网request里面放置属性了。
jiangmodle数据填充到request中
