奇怪的400 BAD REQUEST

    项目以Spring MVC + Hibernate 为后台，前台通过Jquery的AJAX对象，向后台POST一个JSON对象，Spring MVC的Controller方法通过@RequestBody自动转换成POJO对象。

 

在测试的时候，通过httpwatch发现前台总是收到Error 400 BAD_REQUEST错误信息，并且请求时content-length始终为0.

 

而后台的日志则显示如下：

2013-12-31 09:47:46,700 DEBUG [13180593@qtp-459327-2] (DispatcherServlet.java:823) - DispatcherServlet with name 'SpringServlet' processing POST request for [/ma/um/saveuser.do]
2013-12-31 09:47:46,700 DEBUG [13180593@qtp-459327-2] (AbstractHandlerMethodMapping.java:220) - Looking up handler method for path /um/saveuser.do
2013-12-31 09:47:46,700 DEBUG [13180593@qtp-459327-2] (AbstractHandlerMethodMapping.java:227) - Returning handler method [public com.zhiqiang.ma.um.entity.Person com.zhiqiang.ma.um.controller.UserController.saveuser(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse,com.zhiqiang.ma.um.entity.Person)]
2013-12-31 09:47:46,701 DEBUG [13180593@qtp-459327-2] (AbstractBeanFactory.java:246) - Returning cached instance of singleton bean 'userController'
2013-12-31 09:47:46,701 DEBUG [13180593@qtp-459327-2] (AbstractMessageConverterMethodArgumentResolver.java:140) - Reading [class com.zhiqiang.ma.um.entity.Person] as "application/json;charset=UTF-8" using [org.springframework.http.converter.json.MappingJacksonHttpMessageConverter@e9fc96]
2013-12-31 09:47:46,702 DEBUG [13180593@qtp-459327-2] (AbstractHandlerExceptionResolver.java:132) - Resolving exception from handler [public com.zhiqiang.ma.um.entity.Person com.zhiqiang.ma.um.controller.UserController.saveuser(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse,com.zhiqiang.ma.um.entity.Person)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: No content to map to Object due to end of input; nested exception is java.io.EOFException: No content to map to Object due to end of input
2013-12-31 09:47:46,705 DEBUG [13180593@qtp-459327-2] (AbstractHandlerExceptionResolver.java:132) - Resolving exception from handler [public com.zhiqiang.ma.um.entity.Person com.zhiqiang.ma.um.controller.UserController.saveuser(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse,com.zhiqiang.ma.um.entity.Person)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: No content to map to Object due to end of input; nested exception is java.io.EOFException: No content to map to Object due to end of input
2013-12-31 09:47:46,706 DEBUG [13180593@qtp-459327-2] (AbstractHandlerExceptionResolver.java:132) - Resolving exception from handler [public com.zhiqiang.ma.um.entity.Person com.zhiqiang.ma.um.controller.UserController.saveuser(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse,com.zhiqiang.ma.um.entity.Person)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: No content to map to Object due to end of input; nested exception is java.io.EOFException: No content to map to Object due to end of input
2013-12-31 09:47:46,708 DEBUG [13180593@qtp-459327-2] (DispatcherServlet.java:999) - Null ModelAndView returned to DispatcherServlet with name 'SpringServlet': assuming HandlerAdapter completed request handling
2013-12-31 09:47:46,708 DEBUG [13180593@qtp-459327-2] (FrameworkServlet.java:966) - Successfully completed request

 

根据日志分析得出，jquery并没有将数据发送到MappingJacksonHttpMessageConverter，所以才会报错。

 

多天以来度娘、谷哥给予了很大的帮助，后来发现原来是httpwatch在捣乱，将httpwatch关闭后，问题解决了。附代码仅供参考。

1.后台XML配置

<mvc:annotation-driven />
	
	
	<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
	
	<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" >
		<property name="messageConverters">
			<list>
				<ref bean="mappingJacksonHttpMessageConverter"/>
			</list>
		</property>
	</bean>
	 
	<bean id="mappingJacksonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
		<property name="supportedMediaTypes">
			<list>
				<value>text/html;charset=UTF-8</value>
				<value>application/json;charset=UTF-8</value>
				<value>application/x-www-form-urlencoded</value>
			</list>
		</property>
	</bean>

 2.Contorller方法

@RequestMapping(value="/um/saveuser.do",method = RequestMethod.POST)
	public  @ResponseBody Person saveuser(HttpServletRequest request,HttpServletResponse response,@RequestBody Person user){
		log.debug(user.toString());
		return user;
	}

 3.前台代码

<%@ page language="java" contentType="text/html;charset=utf-8" pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script src="../script/jquery-1.10.2.min.js"></script>
<script>
var cfg = {
        type: 'POST', 
        data: JSON.stringify({userName:'测试用户',password:'password'}), 
        dataType: 'json',
        contentType:'application/json;charset=UTF-8',        
        success: function(result) { 
            alert(result); 
        } 
    };

function doTestJson(actionName){
    cfg.url = actionName;
    $.ajax(cfg);
}
</script>
</head>
<body>
	<a href="#" onClick="doTestJson('saveuser.do');">jsonlogin</a>

</body>
</html>

 

参考：

  http://bugs.jquery.com/ticket/12790