SpringMVC4.0以后版本返回json格式数据问题，有什么偏颇的地方希望大家多多斧正。在这个问题上困扰了我两天，这两天翻来覆去睡不着。一直在想这个问题。废话不多说下面进入正题。
1.创建创建web项目，加入SpringMVC的jar,我这里演示用spring-framework-4.2.3.RELEASE。jar包如下图所示：
2.配置web.xml如下：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>SpringMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>SpringMVC</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
3.配置applicationContext.xml
<?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:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
<context:component-scan base-package="cn.xugang.."></context:component-scan>
<mvc:annotation-driven content-negotiation-manager="contentNegotiationManagerFactoryBean"/>
<mvc:default-servlet-handler/>
<bean class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean" id="contentNegotiationManagerFactoryBean">
<property name="favorPathExtension" value="false"/>
<property name="favorParameter" value="false"/>
<property name="ignoreAcceptHeader" value="false"/>
<property name="mediaTypes">
<map>
<entry key="xml" value="application/xml"/>
<entry key="json" value="application/json"/>
<entry key="xls" value="application/vnd.ms-excel"/>
</map>
</property>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" id="mappingJacksonHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
</list>
</property>
</bean>
<bean id="annotationMethodHandlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="mappingJacksonHttpMessageConverter"/>
</list>
</property>
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>
4.配置创建controller，使用@Responsebody注解，指定返回内容。
package cn.xugang.cotroller;
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.ResponseBody;
import cn.xugang.entity.User;
@Controller
@RequestMapping("/user")
public class UserCotroller {
@RequestMapping(value="/hello.html",method=RequestMethod.GET )
public @ResponseBody User hello(){
User user=new User();
user.setAge(19);
user.setName("test");
return user;
}
@RequestMapping(value="/test.html")
public String test(){
System.out.println("hello world");
return "hello";
}
}
5.发送异步请求。这个由于本人用了Etx.js，就直接用ext.js发送异步请求了。
Ext.onReady(function(){
Ext.define('User',{
extend:'Ext.data.Model',
fields:['name','age'],
});
var store=Ext.create('Ext.data.Store',{
model:'User',
proxy:{
type:'ajax',
url:'/SpringMVC4/user/hello.html',
reader:{
type:'json',
}
}
});
store.load({
callback:function(records,operation,success){
if(success){
var msg=[];
store.each(function(user){
msg.push(user.get('name')+" "+user.get('age'));
});
Ext.MessageBox.alert("提示",msg.join("<br>"));
}
}
});
var msg=[];
store.each(function(user){
msg.push(person.get('name')+" "+user.get('age'));
});
Ext.MessageBox.alert('提示',msg.join("<br>"));
});
6.结果演示
7.总结：最后简单说一下，SpringMVC4.0以上版本用上述这种方式成功返回json，如果是4.0以下，由于json的解析方式不同，这里也是一个坑，在网上收了很多资料，看了说得是云里雾里，完全无法使用，最后经过自己认真总结得出本文所述内容，4.0以下可使用如下jar包。
并于applicationContext.xml中配置如下代码
<?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:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
<context:component-scan base-package="cn.xugang.."></context:component-scan>
<mvc:annotation-driven/>
<mvc:default-servlet-handler/>
<bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" id="mappingJacksonHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>
最后，希望帖子对大家有用，由于第一次写，很多地方写的不是很好，请大家多多包涵.如大家对上述有疑惑，可以留言。如转载请注明出处。谢谢大家！