跟开涛学SpringMVC（8）：Controller接口控制器详解（5）

//判断方法是否是功能处理方法 private boolean isHandlerMethod(Method method) {     //得到方法返回值类型  Class returnType = method.getReturnType();     //返回值类型必须是ModelAndView、Map、String、void中的一种，否则不是功能处理方法  if (ModelAndView.class.equals(returnType) || Map.class.equals(returnType) || String.class.equals(returnType) ||    void.class.equals(returnType)) {   Class[] parameterTypes = method.getParameterTypes();         //功能处理方法参数个数必须>=2，且第一个是HttpServletRequest类型、第二个是HttpServletResponse         //且不能Controller接口的handleRequest(HttpServletRequest request, HttpServletResponse response)，这个方法是由系统调用   return (parameterTypes.length >= 2 &&     HttpServletRequest.class.equals(parameterTypes[0]) &&     HttpServletResponse.class.equals(parameterTypes[1]) &&     !("handleRequest".equals(method.getName()) && parameterTypes.length == 2));  }  return false; }

//是否是异常处理方法 private boolean isExceptionHandlerMethod(Method method) {     //异常处理方法必须是功能处理方法 且 参数长度为3、第三个参数类型是Throwable子类  return (isHandlerMethod(method) &&    method.getParameterTypes().length == 3 &&    Throwable.class.isAssignableFrom(method.getParameterTypes()[2])); }

private void registerHandlerMethods(Object delegate) {     //缓存Map清空  this.handlerMethodMap.clear();  this.lastModifiedMethodMap.clear();  this.exceptionHandlerMap.clear();      //得到委托对象的所有public方法  Method[] methods = delegate.getClass().getMethods();  for (Method method : methods) {         //验证是否是异常处理方法，如果是放入exceptionHandlerMap缓存map   if (isExceptionHandlerMethod(method)) {    registerExceptionHandlerMethod(method);   }         //验证是否是功能处理方法，如果是放入handlerMethodMap缓存map   else if (isHandlerMethod(method)) {    registerHandlerMethod(method);    registerLastModifiedMethodIfExists(delegate, method);   }  } }

protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)   throws Exception {  try {         //1、使用methodNameResolver 方法名解析器根据请求解析到要执行的功能方法的方法名   String methodName = this.methodNameResolver.getHandlerMethodName(request);         //2、调用功能方法（通过反射调用，此处就粘贴代码了）   return invokeNamedMethod(methodName, request, response);  }  catch (NoSuchRequestHandlingMethodException ex) {   return handleNoSuchRequestHandlingMethod(ex, request, response);  } }

<property name="methodParamNames" value="list,create,update"/>

for (String suffix : SUBMIT_IMAGE_SUFFIXES)  {//SUBMIT_IMAGE_SUFFIXES {“.x”, “.y”}     if (request.getParameter(name + suffix) != null) {// name是我们配置的methodParamNames         return true;     } }

<property name="logicalMappings">            <props>                <prop key="doList">list</prop>            </props>        </property>

<bean id="propertiesMethodNameResolver"  class="org.springframework.web.servlet.mvc.multiaction.PropertiesMethodNameResolver">     <property name="mappings">         <props>               <prop key="/create">create</prop>               <prop key="/update">update</prop>               <prop key="/delete">delete</prop>               <prop key="/list">list</prop>               <!-- 默认的行为 -->               <prop key="/**">list</prop>         </props>     </property> </bean>

package cn.javass.chapter4.web.controller; //省略import public class UserController extends MultiActionController {     //用户服务类  private UserService userService;  //逻辑视图名 通过依赖注入方式注入，可配置  private String createView;  private String updateView;  private String deleteView;  private String listView;  private String redirectToListView;  //省略setter/getter   public String create(HttpServletRequest request, HttpServletResponse response, UserModel user) {   if("GET".equals(request.getMethod())) {    //如果是get请求 我们转向 新增页面    return getCreateView();   }   userService.create(user);   //直接重定向到列表页面   return getRedirectToListView();  }  public ModelAndView update(HttpServletRequest request, HttpServletResponse response, UserModel user) {   if("GET".equals(request.getMethod())) {    //如果是get请求 我们转向更新页面    ModelAndView mv = new ModelAndView();    //查询要更新的数据    mv.addObject("command", userService.get(user.getUsername()));    mv.setViewName(getUpdateView());    return mv;   }   userService.update(user);   //直接重定向到列表页面   return new ModelAndView(getRedirectToListView());  }   public ModelAndView delete(HttpServletRequest request, HttpServletResponse response, UserModel user) {   if("GET".equals(request.getMethod())) {    //如果是get请求 我们转向删除页面    ModelAndView mv = new ModelAndView();    //查询要删除的数据    mv.addObject("command", userService.get(user.getUsername()));    mv.setViewName(getDeleteView());    return mv;   }   userService.delete(user);   //直接重定向到列表页面   return new ModelAndView(getRedirectToListView());  }    public ModelAndView list(HttpServletRequest request, HttpServletResponse response) {   ModelAndView mv = new ModelAndView();   mv.addObject("userList", userService.list());   mv.setViewName(getListView());   return mv;  }   //如果使用委托方式，命令对象名称只能是command  protected String getCommandName(Object command) {   //命令对象的名字 默认command   return "command";  } }

<bean id="userService" class="cn.javass.chapter4.service.UserService"/>    <bean name="/user/**" class="cn.javass.chapter4.web.controller.UserController">        <property name="userService" ref="userService"/>        <property name="createView" value="user/create"/>        <property name="updateView" value="user/update"/>        <property name="deleteView" value="user/delete"/>        <property name="listView" value="user/list"/>        <property name="redirectToListView" value="redirect:/user/list"/>        <!-- 使用PropertiesMethodNameResolver来解析功能处理方法名 -->               <!--property name="methodNameResolver" ref="propertiesMethodNameResolver"/-->    </bean>

<a href="${pageContext.request.contextPath}/user/create">用户新增</a><br/> <table border="1" width="50%">    <tr>       <th>用户名</th>       <th>真实姓名</th>       <th>操作</th>    </tr>     <c:forEach items="${userList}" var="user">    <tr>       <td>${user.username }</td>       <td>${user.realname }</td>       <td>           <a href="${pageContext.request.contextPath}/user/update?username=${user.username}">更新</a>           |           <a href="${pageContext.request.contextPath}/user/delete?username=${user.username}">删除</a>       </td>    </tr>    </c:forEach>    </table>

<form action="${pageContext.request.contextPath}/user/update" method="post"> 用户名： <input type="text" name="username" value="${command.username}"/><br/> 真实姓名：<input type="text" name="realname" value="${command.realname}"/><br/> <input type="submit" value="更新"/> </form>

<bean id="propertiesMethodNameResolver"  class="org.springframework.web.servlet.mvc.multiaction.PropertiesMethodNameResolver">     <property name="mappings">         <props>               <prop key="/user/create">create</prop>               <prop key="<span style="font-size: 1em; line-height: 1.5;">/user/</span><span style="font-size: 1em; line-height: 1.5;">update">update</prop></span>               <prop key="<span style="font-size: 1em; line-height: 1.5;">/user/</span><span style="font-size: 1em; line-height: 1.5;">delete">delete</prop></span>               <prop key="<span style="font-size: 1em; line-height: 1.5;">/user/</span><span style="font-size: 1em; line-height: 1.5;">list">list</prop></span>               <prop key="/**">list</prop><!-- 默认的行为 -->           </props>     </property>     <property name="alwaysUseFullPath" value="false"/><!-- 不使用全路径 --> </bean>    <bean name="/user/**" class="cn.javass.chapter4.web.controller.UserController">        <!—省略其他配置，详见配置文件-->        <!-- 使用PropertiesMethodNameResolver来解析功能处理方法名 -->               <property name="methodNameResolver" ref="propertiesMethodNameResolver"/> </bean>

<!—委托对象--> <bean id="userDelegate" class="cn.javass.chapter4.web.controller.UserDelegate">    <property name="userService" ref="userService"/>    <property name="createView" value="user2/create"/>    <property name="updateView" value="user2/update"/>    <property name="deleteView" value="user2/delete"/>    <property name="listView" value="user2/list"/>    <property name="redirectToListView" value="redirect:/user2/list"/> </bean> <!—控制器对象--> <bean name="/user2/**"  class="org.springframework.web.servlet.mvc.multiaction.MultiActionController"> <property name="delegate" ref="userDelegate"/>     <property name="methodNameResolver" ref="parameterMethodNameResolver"/> </bean>

<!—ParameterMethodNameResolver --> <bean id="parameterMethodNameResolver"  class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver"> <!-- 1、根据请求参数名解析功能方法名 -->     <property name="methodParamNames" value="create,update,delete"/>     <!-- 2、根据请求参数名的值解析功能方法名 -->     <property name="paramName" value="action"/> <!-- 3、逻辑方法名到真实方法名的映射 -->     <property name="logicalMappings">        <props>            <prop key="doList">list</prop>        </props>     </property>     <!—4、默认执行的功能处理方法 -->     <property name="defaultMethodName" value="list"/> </bean>

<a href="${pageContext.request.contextPath}/user2?action=create">用户新增</a><br/> <table border="1" width="50%">    <tr>       <th>用户名</th>       <th>真实姓名</th>       <th>操作</th>    </tr>     <c:forEach items="${userList}" var="user">    <tr>       <td>${user.username }</td>       <td>${user.realname }</td>       <td>           <a href="${pageContext.request.contextPath}/user2?action=update&username=${user.username}">更新</a>           |           <a href="${pageContext.request.contextPath}/user2?action=delete&username=${user.username}">删除</a>       </td>    </tr>    </c:forEach>    </table>

<form action="${pageContext.request.contextPath}/user2" method="post"> <input type="hidden" name="action" value="update"/> 用户名： <input type="text" name="username" value="${command.username}"/><br/> 真实姓名：<input type="text" name="realname" value="${command.realname}"/><br/> <input type="submit" value="更新"/> </form>

<form action="${pageContext.request.contextPath}/user2" method="post"> 用户名： <input type="text" name="username" value="${command.username}"/><br/> 真实姓名：<input type="text" name="realname" value="${command.realname}"/><br/> <input type="submit" name="create" value="新增"/> </form>