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SpringMVC轻松学习-其他常用(四)

Spring MVC 3.0 深入

核心原理

1.      用户发送请求给服务器。url:user.do

2.      服务器收到请求。发现DispatchServlet可以处理。于是调用DispatchServlet。

3.      DispatchServlet内部,通过HandleMapping检查这个url有没有对应的Controller。如果有,则调用Controller。

4.      Controller开始执行。

5.      Controller执行完毕后,如果返回字符串,则ViewResolver将字符串转化成相应的视图对象;如果返回ModelAndView对象,该对象本身就包含了视图对象信息。

6.      DispatchServlet将执视图对象中的数据,输出给服务器。

7.      服务器将数据输出给客户端。

spring3.0中相关jar包的含义

org.springframework.aop-3.0.3.RELEASE.jar



spring的aop面向切面编程



org.springframework.asm-3.0.3.RELEASE.jar



spring独立的asm字节码生成程序



org.springframework.beans-3.0.3.RELEASE.jar



IOC的基础实现



org.springframework.context-3.0.3.RELEASE.jar



IOC基础上的扩展服务



org.springframework.core-3.0.3.RELEASE.jar



spring的核心包



org.springframework.expression-3.0.3.RELEASE.jar



spring的表达式语言



org.springframework.web-3.0.3.RELEASE.jar



web工具包



org.springframework.web.servlet-3.0.3.RELEASE.jar



mvc工具包







@Controller控制器定义

和Struts1一样,Spring的Controller是Singleton的。这就意味着会被多个请求线程共享。因此,我们将控制器设计成无状态类。


 

在spring 3.0中,通过@controller标注即可将class定义为一个controller类。为使spring能找到定义为controller的bean,需要在spring-context配置文件中增加如下定义:


 

<context:component-scanbase-package="com.sxt.web"/>





         注:实际上,使用@component,也可以起到@Controller同样的作用。


 

@RequestMapping


 

    在类前面定义,则将url和类绑定。

       在方法前面定义,则将url和类的方法绑定,如下所示:

package com.sxt.web;





import javax.annotation.Resource;


import org.springframework.stereotype.Controller;


import org.springframework.web.bind.annotation.RequestMapping;


import com.sxt.service.UserService;





@Controller


@RequestMapping("/user.do")


publicclass UserController {





@Resource


private UserService userService;





//http://localhost:8080/springmvc02/user.do?method=reg&uname=zzzz


@RequestMapping(params="method=reg")


public String reg(String uname) {


System.out.println("HelloController.handleRequest()");


userService.add(uname);


return "index";


}





public UserService getUserService() {


return userService;


}


publicvoid setUserService(UserService userService) {


this.userService = userService;


}








}


 

@RequestParam

         一般用于将指定的请求参数付给方法中形参。示例代码如下:

        

@RequestMapping(params="method=reg5")


public String reg5(@RequestParam("name")String uname,ModelMap map) {


System.out.println("HelloController.handleRequest()");


System.out.println(uname);


return "index";


}

        

         这样,就会将name参数的值付给uname。当然,如果请求参数名称和形参名称保持一致,则不需要这种写法。

@SessionAttributes

    将ModelMap中指定的属性放到session中。示例代码如下:

   

@Controller


@RequestMapping("/user.do")


@SessionAttributes({"u","a"}) //将ModelMap中属性名字为u、a的再放入session中。这样,request和session中都有了。


publicclass UserController {


@RequestMapping(params="method=reg4")


public String reg4(ModelMap map) { System.out.println("HelloController.handleRequest()");


map.addAttribute("u","uuuu"); //将u放入request作用域中,这样转发页面也可以取到这个数据。


return "index";


}


}

<body>


<h1>**********${requestScope.u.uname}</h1>


<h1>**********${sessionScope.u.uname}</h1>


</body>

   

    注:名字为”user”的属性再结合使用注解@SessionAttributes可能会报错。


 

@ModelAttribute

      ​​这个注解可以跟@SessionAttributes配合在一起用。可以将ModelMap​​中属性的值通过该注解自动赋给指定变量。

    示例代码如下:

package com.sxt.web;


import javax.annotation.Resource;


import org.springframework.stereotype.Controller;


import org.springframework.ui.ModelMap;


import org.springframework.web.bind.annotation.ModelAttribute;


import org.springframework.web.bind.annotation.RequestMapping;


import org.springframework.web.bind.annotation.SessionAttributes;


@Controller


@RequestMapping("/user.do")


@SessionAttributes({"u","a"})


publicclass UserController {





@RequestMapping(params="method=reg4")


public String reg4(ModelMap map) {


System.out.println("HelloController.handleRequest()");


map.addAttribute("u","尚学堂高淇");


return "index";


}





@RequestMapping(params="method=reg5")


public String reg5(@ModelAttribute("u")String uname​​[微软用户1]​​ ,ModelMap map) {


System.out.println("HelloController.handleRequest()");


System.out.println(uname);


return "index";


}





}


 

先调用reg4方法,再调用reg5方法。我们发现控制台打印出来:尚学堂高淇


 

Controller类中方法参数的处理


 

Controller类中方法返回值的处理

1.      返回string(建议)

a)        根据返回值找对应的显示页面。路径规则为:prefix前缀+返回值+suffix后缀组成

b)        代码如下:

@RequestMapping(params="method=reg4")


public String reg4(ModelMap map) {


System.out.println("HelloController.handleRequest()");


return "index";


}

前缀为:/WEB-INF/jsp/    后缀是:.jsp

在转发到:/WEB-INF/jsp/index.jsp


 

2.      也可以返回ModelMap、ModelAndView、map、List、Set、Object、无返回值。一般建议返回字符串!


 


 

请求转发和重定向

         代码示例:

        

package com.sxt.web;





import javax.annotation.Resource;


import org.springframework.stereotype.Controller;


import org.springframework.ui.ModelMap;


import org.springframework.web.bind.annotation.ModelAttribute;


import org.springframework.web.bind.annotation.RequestMapping;


import org.springframework.web.bind.annotation.SessionAttributes;





@Controller


@RequestMapping("/user.do")


publicclass UserController {





@RequestMapping(params="method=reg4")


public String reg4(ModelMap map) {


System.out.println("HelloController.handleRequest()");


// return "forward:index.jsp";


// return "forward:user.do?method=reg5"; //转发


// return "redirect:user.do?method=reg5"; //重定向


return "redirect:http://www.baidu.com"; //重定向


}





@RequestMapping(params="method=reg5")


public String reg5(String uname,ModelMap map) {


System.out.println("HelloController.handleRequest()");


System.out.println(uname);


return "index";


}





}

        

         访问reg4方法,既可以看到效果。


 


 


 

获得request对象、session对象

普通的Controller类,示例代码如下:

@Controller


@RequestMapping("/user.do")


publicclass UserController {





@RequestMapping(params="method=reg2")


public String reg2(String uname,HttpServletRequest req,ModelMap map){


req.setAttribute("a", "aa");


req.getSession().setAttribute("b", "bb");


return "index";


}


}


 


 

ModelMap

         是map的实现,可以在其中存放属性,作用域同request。下面这个示例,我们可以在modelMap中放入数据,然后在forward的页面上显示这些数据。通过el表达式、JSTL、java代码均可。代码如下:

        

package com.sxt.web;





import org.springframework.stereotype.Controller;


import org.springframework.ui.ModelMap;


import org.springframework.web.bind.annotation.RequestMapping;


import org.springframework.web.servlet.mvc.multiaction.MultiActionController;





@Controller


@RequestMapping("/user.do")


publicclass UserController extends MultiActionController {





@RequestMapping(params="method=reg")


public String reg(String uname,ModelMap map){


map.put("a", "aaa");


return "index";


}


}

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head></head>


<body>


<h1>${requestScope.a}</h1>


<c:outvalue="${requestScope.a}"></c:out>


</body>


</html>


 

ModelAndView模型视图类

见名知意,从名字上我们可以知道ModelAndView中的Model代表模型,View代表视图。即,这个类把要显示的数据存储到了Model属性中,要跳转的视图信息存储到了view属性。我们看一下ModelAndView的部分源码,即可知其中关系:

publicclassModelAndView





/** View instance or view name String */


private Object view;





/** Model Map */


private ModelMap model;





/**


* Indicates whether or not this instance has been cleared with a call to {@link #clear()}.


*/


privateboolean cleared = false;








/**


* Default constructor for bean-style usage: populating bean


* properties instead of passing in constructor arguments.


* @see #setView(View)


* @see #setViewName(String)


*/


public ModelAndView() {


}





/**


* Convenient constructor when there is no model data to expose.


* Can also be used in conjunction with <code>addObject</code>.


* @param viewName name of the View to render, to be resolved


* by the DispatcherServlet's ViewResolver


* @see #addObject


*/


public ModelAndView(String viewName) {


this.view = viewName;


}





/**


* Convenient constructor when there is no model data to expose.


* Can also be used in conjunction with <code>addObject</code>.


* @param view View object to render


* @see #addObject


*/


public ModelAndView(View view) {


this.view = view;


}





/**


* Creates new ModelAndView given a view name and a model.


* @param viewName name of the View to render, to be resolved


* by the DispatcherServlet's ViewResolver


* @param model Map of model names (Strings) to model objects


* (Objects). Model entries may not be <code>null</code>, but the


* model Map may be <code>null</code> if there is no model data.


*/


public ModelAndView(String viewName, Map<String, ?> model) {


this.view = viewName;


if (model != null) {


getModelMap().addAllAttributes(model);


}


}





/**


* Creates new ModelAndView given a View object and a model.


* <emphasis>Note: the supplied model data is copied into the internal


* storage of this class. You should not consider to modify the supplied


* Map after supplying it to this class</emphasis>


* @param view View object to render


* @param model Map of model names (Strings) to model objects


* (Objects). Model entries may not be <code>null</code>, but the


* model Map may be <code>null</code> if there is no model data.


*/


public ModelAndView(View view, Map<String, ?> model) {


this.view = view;


if (model != null) {


getModelMap().addAllAttributes(model);


}


}





/**


* Convenient constructor to take a single model object.


* @param viewName name of the View to render, to be resolved


* by the DispatcherServlet's ViewResolver


* @param modelName name of the single entry in the model


* @param modelObject the single model object


*/


public ModelAndView(String viewName, String modelName, Object modelObject) {


this.view = viewName;


addObject(modelName, modelObject);


}





/**


* Convenient constructor to take a single model object.


* @param view View object to render


* @param modelName name of the single entry in the model


* @param modelObject the single model object


*/


public ModelAndView(View view, String modelName, Object modelObject) {


this.view = view;


addObject(modelName, modelObject);


}








/**


* Set a view name for this ModelAndView, to be resolved by the


* DispatcherServlet via a ViewResolver. Will override any


* pre-existing view name or View.


*/


publicvoid setViewName(String viewName) {


this.view = viewName;


}





/**


* Return the view name to be resolved by the DispatcherServlet


* via a ViewResolver, or <code>null</code> if we are using a View object.


*/


public String getViewName() {


return (this.view instanceof String ? (String) this.view : null);


}





/**


* Set a View object for this ModelAndView. Will override any


* pre-existing view name or View.


*/


publicvoid setView(View view) {


this.view = view;


}





/**


* Return the View object, or <code>null</code> if we are using a view name


* to be resolved by the DispatcherServlet via a ViewResolver.


*/


public View getView() {


return (this.view instanceof View ? (View) this.view : null);


}





/**


* Indicate whether or not this <code>ModelAndView</code> has a view, either


* as a view name or as a direct {@link View} instance.


*/


publicboolean hasView() {


return (this.view != null);


}





/**


* Return whether we use a view reference, i.e. <code>true</code>


* if the view has been specified via a name to be resolved by the


* DispatcherServlet via a ViewResolver.


*/


publicboolean isReference() {


return (this.view instanceof String);


}





/**


* Return the model map. May return <code>null</code>.


* Called by DispatcherServlet for evaluation of the model.


*/


protected Map<String, Object> getModelInternal() {


returnthis.model;


}





/**


* Return the underlying <code>ModelMap</code> instance (never <code>null</code>).


*/


public ModelMap getModelMap() {


if (this.model == null) {


this.model = new ModelMap();


}


returnthis.model;


}





/**


* Return the model map. Never returns <code>null</code>.


* To be called by application code for modifying the model.


*/


public Map<String, Object> getModel() {


return getModelMap();


}








/**


* Add an attribute to the model.


* @param attributeName name of the object to add to the model


* @param attributeValue object to add to the model (never <code>null</code>)


* @see ModelMap#addAttribute(String, Object)


* @see #getModelMap()


*/


publicModelAndView


getModelMap().addAttribute(attributeName, attributeValue);


returnthis;


}





/**


* Add an attribute to the model using parameter name generation.


* @param attributeValue the object to add to the model (never <code>null</code>)


* @see ModelMap#addAttribute(Object)


* @see #getModelMap()


*/


publicModelAndView


getModelMap().addAttribute(attributeValue);


returnthis;


}





/**


* Add all attributes contained in the provided Map to the model.


* @param modelMap a Map of attributeName -> attributeValue pairs


* @see ModelMap#addAllAttributes(Map)


* @see #getModelMap()


*/


publicModelAndView


getModelMap().addAllAttributes(modelMap);


returnthis;


}








/**


* Clear the state of this ModelAndView object.


* The object will be empty afterwards.


* <p>Can be used to suppress rendering of a given ModelAndView object


* in the <code>postHandle</code> method of a HandlerInterceptor.


* @see #isEmpty()


* @see HandlerInterceptor#postHandle


*/


publicvoid clear() {


this.view = null;


this.model = null;


this.cleared = true;


}





/**


* Return whether this ModelAndView object is empty,


* i.e. whether it does not hold any view and does not contain a model.


*/


publicboolean isEmpty() {


return (this.view == nullisEmpty(this.model));


}





/**


* Return whether this ModelAndView object is empty as a result of a call to {@link #clear}


* i.e. whether it does not hold any view and does not contain a model.


* <p>Returns <code>false</code> if any additional state was added to the instance


* <strong>after</strong> the call to {@link #clear}.


* @see #clear()


*/


publicboolean wasCleared() {


return (this.cleared && isEmpty());


}








/**


* Return diagnostic information about this model and view.


*/


@Override


public String toString() {


StringBuilder sb = new StringBuilder("ModelAndView: ");


if (isReference()) {


sb.append("reference to view with name '").append(this.view).append("'");


}


else {


sb.append("materialized View is [").append(this.view).append(']');


}


sb.append("; model is ").append(this.model);


return sb.toString();


}


}


 

测试代码如下:

package com.sxt.web;





import org.springframework.stereotype.Controller;


import org.springframework.web.bind.annotation.RequestMapping;


import org.springframework.web.servlet.ModelAndView;


import org.springframework.web.servlet.mvc.multiaction.MultiActionController;





import com.sxt.po.User;





@Controller


@RequestMapping("/user.do")


publicclass UserController extends MultiActionController {





@RequestMapping(params="method=reg")


publicString uname){


mvnew ModelAndView();


mv.setViewName("index");


// mv.setView(new RedirectView("index"));





User u = new User();


u.setUname("高淇");


mv.addObject(u); //查看源代码,得知,直接放入对象。属性名为”首字母小写的类名”。 一般建议手动增加属性名称。


mv.addObject("a", "aaaa");


returnmv;


}





}

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>


</head>


<body>


<h1>${requestScope.a}</h1>


<h1>${requestScope.user.uname}</h1>


</body>


</html>

地址栏输入:​​http://localhost:8080/springmvc03/user.do?method=reg​​

结果为:



 


 

基于spring 3.0mvc 框架的文件上传实现

1. spring使用了apache-commons下得上传组件,因此,我们需要引入两个jar包:

1.      apache-commons-fileupload.jar

2.      apache-commons-io.jar


 

2.  在springmvc-servlet.xml配置文件中,增加CommonsMultipartResoler配置:

<!-- 处理文件上传 -->


<beanid="multipartResolver"


class="org.springframework.web.multipart.commons.CommonsMultipartResolver" >


<propertyname="defaultEncoding" value="gbk"/> <!-- 默认编码 (ISO-8859-1) -->


<propertyname="maxInMemorySize" value="10240"/> <!-- 最大内存大小 (10240)-->


<propertyname="uploadTempDir" value="/upload/"/> <!-- 上传后的目录名 (WebUtils#TEMP_DIR_CONTEXT_ATTRIBUTE) -->


<propertyname="maxUploadSize" value="-1"/> <!-- 最大文件大小,-1为无限止(-1) -->


</bean>


 

3.  建立upload.jsp页面,内容如下:

        

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>


<title>测试springmvc中上传的实现</title>


</head>


<body>


<formaction="upload.do" method="post" enctype="multipart/form-data">


<inputtype="text" name="name" />


<inputtype="file" name="file" />


<inputtype="submit" />


</form>


</body>


</html>


 

4. 建立控制器,代码如下:

        

package  com.sxt.web;



import java.io.File;
import java.util.Date;



import javax.servlet.ServletContext;



import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.multipart.commons.CommonsMultipartFile;



@Controller
public class FileUploadController implements ServletContextAware {



private ServletContext servletContext;

@Override
public void setServletContext(ServletContext context) {
this.servletContext = context;
}

@RequestMapping(value="/upload.do", method = RequestMethod.POST)
@RequestParam("file")​​[微软用户2]​​ CommonsMultipartFile file){
if (!file.isEmpty()) {
String path = this.servletContext.getRealPath("/tmp/"); //获取本地存储路径
System.out.println(path);
String fileName = file.getOriginalFilename();
String fileType = fileName.substring(fileName.lastIndexOf("."));
System.out.println(fileType);
File file2 = new File(path,new Date().getTime() + fileType); //新建一个文件
try {
file.getFileItem().write(file2); //将上传的文件写入新建的文件中
} catch (Exception e) {
e.printStackTrace();
}
return "redirect:upload_ok.jsp";
}else{
return "redirect:upload_error.jsp";
}
}
}


 

5. 建立upload_ok.jsp页面

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>


</head>


<body>


<h1>上传成功!</h1>


</body>


</html>


 

6. 建立upload_error.jsp页面

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>


</head>


<body>


<h1>上传失败!</h1>


</body>


</html>


 

1.      发布项目,运行测试:​​http://localhost:8080/springmvc03/upload.jsp​​

SpringMVC轻松学习-其他常用(四)_java

   进入项目发布后的目录,发现文件上传成功:

SpringMVC轻松学习-其他常用(四)_java_02


 

处理ajax请求

spring使用了jackson类库,帮助我们在java对象和json、xml数据之间的互相转换。他可以将控制器返回的对象直接转换成json数据,供客户端使用。客户端也可以传送json数据到服务器进行直接转换。使用步骤如下:

 

1.  项目中需要引入如下两个jar包:

                  jackson-core-asl-1.7.2jar

                   jackson-mapper-asl-1.7.2jar

2.  spring配置文件中修改:

<mvc:annotation-driven/>  <!-- 支持spring3.0新的mvc注解 -->


<!-- 启动Spring MVC的注解功能,完成请求和注解POJO的映射 -->


<beanclass="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">


<propertyname="cacheSeconds" value="0" />


<propertyname="messageConverters">


<list>


<beanclass="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>


</list>


</property>


</bean>


 

3.      客户端代码a.jsp如下:

<%@page language="java"  import="java.util.*" pageEncoding="gbk"%>


<%


String path = request.getContextPath();


String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";


%>





<!DOCTYPEHTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">


<html>


<head>


<basehref="<%=basePath%>">





<title>My JSP 'index.jsp' starting page</title>


<metahttp-equiv="pragma" content="no-cache">


<metahttp-equiv="cache-control" content="no-cache">


<metahttp-equiv="expires" content="0">


<metahttp-equiv="keywords" content="keyword1,keyword2,keyword3">


<metahttp-equiv="description" content="This is my page">


<script>


function createAjaxObj(){


var req;


if(window.XMLHttpRequest){


req = new XMLHttpRequest();


}else{


req = new ActiveXObject("Msxml2.XMLHTTP"); //ie


}


return req;


}





function sendAjaxReq(){


var req = createAjaxObj();


req.open("get","myajax.do?method=test2&uname=张三");


req.setRequestHeader("accept","application/json");


req.onreadystatechange = function(){


eval("var result="+req.responseText);


document.getElementById("div1").innerHTML=result[0].uname;


}


req.send(null);


}


</script>


</head>





<body>


<ahref="javascript:void(0);" onclick="sendAjaxReq();">测试</a>


<divid="div1"></div>


</body>


</html>


 

4.      服务器端代码如下:

        

package  com.sxt.web;



import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;



import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;



import com.sxt.po.User;



@Controller
@RequestMapping("myajax.do")
public class MyAjaxController {

@RequestMapping(params="method=test1",method=RequestMethod.GET)
public @ResponseBody List<User> test1(String uname) throws Exception{
String uname2 = new String(uname.getBytes("iso8859-1"),"gbk");
System.out.println(uname2);
System.out.println("MyAjaxController.test1()");
List<User> list = new ArrayList<User>();
list.add(new User("高淇","123"));
list.add(new User("马士兵","456"));

return list;
}

}


 


 

5.      测试。

a)        启动服务器。输入:​​http://localhost:8080/springmvc03/a.jsp​​

SpringMVC轻松学习-其他常用(四)_spring_03


 


 


 


 


 


 

Spring中的拦截器

定义spring拦截器两种基本方式

1.      实现接口:org.springframework.web.servlet.HandlerInterceptor。

接口中有如下方法需要重写:

注意:参数中的Object handler是下一个拦截器。

a)        public boolean preHandle
(HttpServletRequest request,HttpServletResponse response,
Object handler) throws Exception

该方法在action执行前执行,可以实现对数据的预处理,比如:编码、安全控制等。

如果方法返回true,则继续执行action。

b)        public void postHandle
(HttpServletRequest request,HttpServletResponse response,
Object handler,   ModelAndViewmodelAndView) throws Exception

该方法在action执行后,生成视图前执行。在这里,我们有机会修改视图层数据。

c)        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex)   throws Exception

最后执行,通常用于释放资源,处理异常。我们可以根据ex是否为空,来进行相关的异常处理。因为我们在平时处理异常时,都是从底层向上抛出异常,最后到了spring框架从而到了这个方法中。

2.      继承适配器:
org.springframework.web.servlet.handler.HandlerInterceptorAdapter

这个适配器实现了HandlerInterceptor接口。提供了这个接口中所有方法的空实现。


 

如下我们写出两个拦截器的示例代码,仅供大家参考:

package com.sxt.interceptor;





importjavax.interceptor.Interceptors;


import javax.servlet.http.HttpServletRequest;


import javax.servlet.http.HttpServletResponse;





import org.springframework.web.servlet.HandlerInterceptor;


import org.springframework.web.servlet.ModelAndView;








publicclass MyInterceptor implements HandlerInterceptor {





@Override


publicvoid afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {


System.out.println("最后执行!!!一般用于释放资源!!");





}





@Override


publicvoid postHandle(HttpServletRequest request,HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {


System.out.println("Action执行之后,生成视图之前执行!!");


}





@Override


publicboolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {


System.out.println("action之前执行!!!");


returntrue; //继续执行action


}





}

package com.sxt.interceptor;





import javax.servlet.http.HttpServletRequest;


import javax.servlet.http.HttpServletResponse;





import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;








publicclass MyInterceptor2 extends HandlerInterceptorAdapter {





@Override


publicboolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {


System.out.println("MyInterceptor2.preHandle()");


returntrue; //继续执行action


}





}


 


 


 

3.      XML中如何配置。如下为示例代码:

<mvc:interceptors>


<beanclass="com.sxt.interceptor.MyInterceptor"></bean> <!-- 拦截所有springmvc的url! -->


<mvc:interceptor>


<mvc:mappingpath="/user.do" />


<!--<mvc:mapping path="/test/*" />-->


<beanclass="com.sxt.interceptor.MyInterceptor2"></bean>


</mvc:interceptor>


</mvc:interceptors>





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