Spring MVC的@ResponseBody返回JSON串
Xml代码
<bean class ="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" > 
    <property name="messageConverters"> 
  <list> 
   <ref bean="mappingJacksonHttpMessageConverter" /><!-- json转换器 --> 
  </list> 
</property> 
</bean>     
<bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" /> 

<bean class ="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" >
    <property name="messageConverters">
  <list>
   <ref bean="mappingJacksonHttpMessageConverter" /><!-- json转换器 -->
  </list>
</property>
</bean>  
<bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />

需要以下两个jar包：

Xml代码
<dependency org="org.codehaus.jackson" name="jackson-core-asl" rev="1.5.5" conf="runtime->default" /> 
<dependency org="org.codehaus.jackson" name="jackson-mapper-asl" rev="1.5.5" conf="runtime->default" /> 

<dependency org="org.codehaus.jackson" name="jackson-core-asl" rev="1.5.5" conf="runtime->default" />
<dependency org="org.codehaus.jackson" name="jackson-mapper-asl" rev="1.5.5" conf="runtime->default" />



Java代码
@RequestMapping(value="/nogood", method=RequestMethod.GET)  
public @ResponseBody CmUser execute(String userid) {  
  CmUser u = new CmUser();  
  u.setAge(16);  
  u.setName("测试用户");  
  return u;  
}