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springMVC3.0（文件上传，@RequestMapping加參数,@SessionAttributes,@ModelAttribute，转发，重定向，数值获取，传參，ajax,拦截器)

1.项目包结构例如以下：

2. spring配置文件springMVC.xml改动例如以下：

3. spring配置文件beans.xml内容改动例如以下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-3.0.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
      http://www.springframework.org/schema/tx
      http://www.springframework.org/schema/tx/spring-tx-3.0.xsd ">

<mvc:annotation-driven/>

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


<bean id="ds" class="com.mchange.v2.c3p0.ComboPooledDataSource">
  <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
  <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/springmvc"></property>
  <property name="user" value="root"></property>
  <property name="password" value="123456"></property>
  <property name="initialPoolSize" value="10"></property>
  <property name="maxPoolSize" value="50"></property>
  <property name="minPoolSize" value="10"></property>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
  <property name="dataSource" ref="ds"></property>

  
  <property name="mappingDirectoryLocations">
   <value>classpath:com/sxt/domain/</value>
  </property>
  <property name="hibernateProperties">
   <props>
    <prop key="hibernate.Dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>
    <prop key="hibernate.show_sql">true</prop>
    <prop key="hibernate.hbm2ddl.auto">update</prop>
   </props>
  </property>
</bean>


<bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
  <property name="sessionFactory" ref="sessionFactory"/>
</bean>


<tx:advice id="txAdvice" transaction-manager="txManager">
  <tx:attributes>
   <tx:method name="save*" propagation="REQUIRED"/>
   <tx:method name="delete*" propagation="REQUIRED"/>
   <tx:method name="update*" propagation="REQUIRED"/>
   <tx:method name="find*" read-only="true"/>
   <tx:method name="*" read-only="true"/>
  </tx:attributes>
</tx:advice>

<aop:config>
  <aop:advisor pointcut="execution(* *..*ServiceImpl.*(..))" advice-ref="txAdvice"/>
  
</aop:config>
</beans>

4. web.xml文件不变

xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">


<context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>classpath:beans.xml</param-value>
</context-param>
<listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
  <servlet-name>action</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <init-param>
   <param-name>contextConfigLocation</param-name>
   <param-value>classpath:springMVC.xml</param-value>
  </init-param>
</servlet>
<servlet-mapping>
  <servlet-name>action</servlet-name>
  <url-pattern>/</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

5. 类的代码不变。

6. 执行，測试。跟上一个项目保持一致。

Spring MVC 3.0 深入

核心原理

1. 用户发送请求给server。

url：user.do

2. server收到请求。

发现 DispatchServlet能够处理。于是调用DispatchServlet。

3. DispatchServlet内部。通过 HandleMapping检查这个url有没有相应的Controller。

假设有。则调用Controller。

4. Controller開始运行。

5. Controller运行完成后。假设返回字符串。则ViewResolver将字符串转化成对应的视图对象；假设返回ModelAndView对象，该对象本身就包括了视图对象信息。

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

7. server将数据输出给client。

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标注就可以将class定义为一个controller类。

为使spring能找到定义为controller的bean,须要在spring-context配置文件里添加例如以下定义：

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

注：实际上，使用@component，也能够起到@Controller相同的作用。

@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，例如以下所看到的：

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 UserServiceuserService;

//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() {

returnuserService;

}

publicvoid setUserService(UserService userService) {

this.userService = userService;

}

@RequestParam

一般用于将指定的请求參数赋给方法中形參。演示样例代码例如以下：

@RequestMapping(params="method=reg5")

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

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

System.out.println(uname);

//通过ModelMap传參

map.put("name", uname);

return"index";

}

这样，就会将name參数的值付给uname。当然。假设请求參数名称和形參名称保持一致，则不须要这样的写法。

@SessionAttributes

将ModelMap中指定的属性放到session中。

演示样例代码例如以下：

@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。这样转发页面也能够取到这个数据。

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

这个注解能够跟@SessionAttributes配合在一起用。能够将ModelMap中属性的值通过该注解自己主动赋给指定变量。

演示样例代码例如以下：

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 ,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类中方法參数的处理

Controller类中方法返回值的处理

1. 返回string(建议)

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

b) 代码例如以下：

@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. 也能够返回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

代码演示样例：

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";

}

訪问reg4方法。既能够看到效果。

获得request对象、session对象

普通的Controller类，演示样例代码例如以下：

@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。能够在当中存放属性，作用域同request。

以下这个演示样例，我们能够在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。

代码例如以下：

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 UserControllerextends 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="utf-8"%>

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

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

<html>

<body>

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

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

</body>

</html>

ModelAndView模型视图类

见名知意，从名字上我们能够知道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的部分源代码。就可以知当中关系：

publicclassModelAndView {

/** View instance or view name String */

private Objectview;

/** Model Map */

private ModelMapmodel;

/**

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

privatebooleancleared =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.viewinstanceof 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.viewinstanceof 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.viewinstanceof 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 addObject(String attributeName, Object attributeValue) {

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 addObject(Object attributeValue) {

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 addAllObjects(Map<String, ?> modelMap) {

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 == null && CollectionUtils.isEmpty(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();

}

測试代码例如以下：

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 UserControllerextends MultiActionController {

@RequestMapping(params="method=reg")

public ModelAndView reg(String uname){

ModelAndView mv = new ModelAndView();

mv.setViewName("index");

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

User u = new User();

u.setUname("高淇");

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

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

returnmv;

}

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

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

<!DOCTYPEHTMLPUBLIC "-//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。我们须要引入两个jar包：

1. apache-commons-fileupload.jar

2. apache-commons-io.jar

2. 在springmvc-servlet.xml配置文件里，添加CommonsMultipartResoler配置：

<beanid="multipartResolver"

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

<propertyname="defaultEncoding"value="gbk"/>

<propertyname="maxInMemorySize"value="10240"/>

<propertyname="uploadTempDir"value="/upload/"/>

<propertyname="maxUploadSize"value="-1"/>

</bean>

3. 建立upload.jsp页面，内容例如以下：

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

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

<html>

<head>

<title>測试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，代码例如以下：

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)

public String handleUploadData(String name,@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里

} 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"%>

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

<html>

<head>

</head>

<body>

</body>

</html>

6. 建立upload_error.jsp页面

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

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

<html>

<head>

</head>

<body>

</body>

</html>

7. 公布项目，执行測试：http://localhost:8080/springmvc03/upload.jsp

进入项目公布后的文件夹，发现文件上传成功：

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。他能够将控制器返回的对象直接转换成json数据，供client使用。client也能够传送json数据到server进行直接转换。

使用过程例如以下：

1. 项目中须要引入例如以下两个jar包：

jackson-core-asl-1.7.2jar

jackson-mapper-asl-1.7.2jar

2. spring配置文件里改动：

<mvc:annotation-driven/>

<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. client代码a.jsp例如以下：

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

String path = request.getContextPath();

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

<!DOCTYPEHTMLPUBLIC "-//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">

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();">測试</a>

<divid="div1"></div>

</body>

</html>

4. server端代码例如以下：

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. 測试。

a) 启动server。

输入：http://localhost:8080/springmvc03/a.jsp

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。

接口中有例如以下方法须要重写：

注意：參数中的Object handler是下一个拦截器。

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

该方法在action运行前运行，能够实现对数据的预处理，比方：编码、安全控制等。

假设方法返回true。则继续运行action。

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

该方法在action运行后，生成视图前运行。

在这里，我们有机会改动视图层数据。

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

最后运行，通经常使用于释放资源，处理异常。

我们能够依据ex是否为空。来进行相关的异常处理。由于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框架从而到了这种方法中。

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

这个适配器实现了HandlerInterceptor接口。提供了这个接口中全部方法的空实现。

例如以下我们写出两个拦截器的演示样例代码，仅供大家參考：

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 MyInterceptorimplements HandlerInterceptor {

@Override

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

System.out.println("最后运行。！！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运行之后，生成视图之前运行。！

");

}

@Override

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

System.out.println("action之前运行！！。");

returntrue; //继续运行action

}

package com.sxt.interceptor;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

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

publicclass MyInterceptor2extends HandlerInterceptorAdapter {

@Override

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

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

returntrue; //继续运行action

}

3. XML中怎样配置。

例如以下为演示样例代码：

<mvc:interceptors>

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

<mvc:interceptor>

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

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

</mvc:interceptor>

</mvc:interceptors>

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原文地址：https://www.cnblogs.com/cxchanpin/p/6944422.html

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