Spring 3.2.* MVC通過Ajax獲取JSON數據報406錯誤

Spring 3.2.x通過@ResponseBody標籤返回JSON數據的方法都報406錯： Failed to load resource: the server responded with a status of 406 (Not Acceptable) 以及報錯描述： The resource identified by this request is only capable of generating responses with characteristics not acceptable according to the request "accept" headers () 於是，百度、Google了半天，發現遇到此問題的人挺多的，但是都是說什麼添加Jackson什麼的，我是採用的fastjson，換成Jackson嘗試了半天均還是406。 後來在stackoverflow有人說是Spring 3.2的BUG，於是退回到3.1.*，不再報406了， 雖然換回3.1不報錯了，但還是想看看在處理ajax返回json數據的方式上兩個版本到底有何區別，debug之。 debug到org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(T returnValue,MethodParameter returnType,ServletServerHttpRequest inputMessage,ServletServerHttpResponse outputMessage)，在以下代碼處拋出了異常：

if (compatibleMediaTypes.isEmpty()) {
        throw new HttpMediaTypeNotAcceptableException(allSupportedMediaTypes);
    }

看來是compatibleMediaTypes爲空導致。看debug信息，經過比較發現3.1的requestedMediaTypes爲[*/*]，而3.2的requestedMediaTypes卻爲[text/html]，producibleMediaTypes都是[application/json],繼而發現獲取acceptableMediaTypes的方式3.1與3.2不同 3.1的

3.1的

private List<MediaType> getAcceptableMediaTypes(HttpInputMessage inputMessage) {
        try {
            List<MediaType> result = inputMessage.getHeaders().getAccept();
            return result.isEmpty() ? Collections.singletonList(MediaType.ALL) : result;
        } catch (IllegalArgumentException ex) {
            if (logger.isDebugEnabled()) {
                logger.debug("Could not parse Accept header: " + ex.getMessage());
            }
            return Collections.emptyList();
        }
    }

3.2的

private List<MediaType> getAcceptableMediaTypes(HttpServletRequest request) throws HttpMediaTypeNotAcceptableException {
        List<MediaType> mediaTypes = this.contentNegotiationManager.resolveMediaTypes(new ServletWebRequest(request));
        return mediaTypes.isEmpty() ? Collections.singletonList(MediaType.ALL) : mediaTypes;
    }

看來問題就是出在這裏了。不知Spring爲何改變該實現方式？？！！ 

解決方法如下：

一、第一種 繼續用Spring 3.1.4。

二、第二種

<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc"

        xsi:schemaLocation="http://www.springframework.org/schema/beans
             http://www.springframework.org/schema/beans/spring-beans-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
             http://www.springframework.org/schema/mvc
             http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

把spring-mvc-3.0.xsd 升級到 spring-mvc-3.2.xsd

<?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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

然後把<mvc:annotation-driven>修改成如下格式

<mvc:annotation-driven content-negotiation-manager="contentNegotiationManager" />
<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
    <property name="favorPathExtension" value="false" />
    <property name="favorParameter" value="false" />
    <property name="ignoreAcceptHeader" value="false" />
    <property name="mediaTypes" >
        <value>
            atom=application/atom+xml
            html=text/html
            json=application/json
            *=*/*
        </value>
    </property>
</bean>

三、第三種

詳情見下面的地址點擊打開鏈接

四、第四種

spring 3.2時requestedMediaTypes卻爲[text/html]的情況報406錯誤，還有一個原因可能是由於採用的後綴有關，如果使用*.htm,*.html等，默認就會採用[text/html]編碼，若改成*.json,*.shtml等就OK