Question

我在我的应用程序中使用Spring MVC。对于某个ajax调用，我需要返回JSON响应。通常你会使用@ReponseBody注释来做到这一点。

这是我用过的一段代码。

@RequestMapping(value ="/getClients", headers="Accept=*/*", produces = "application/json")
public @ResponseBody List<Map<String, Object>> getClients(@ModelAttribute("searchText") String searchText, ModelMap model){
    logger.debug("Entering getClients with searchtext as : {}", searchText);
    List<Map<String, Object>> autoCompleterResult = null;
    try{
        autoCompleterResult = clientService.getClientsForAutoCompleter(searchText);
    logger.debug("Grid Result is : {}", autoCompleterResult );
    }catch(Exception e){
        logger.error("Exception occured", e);
    }
    return autoCompleterResult;
}

这适用于Spring 3.1.4，但不适用于Spring 3.2版本。或者是否需要一些特定的配置才能使其与Spring 3.2一起使用？

MVC配置

  <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
    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-3.1.xsd">
<mvc:annotation-driven />
<mvc:resources location="/css/**" mapping="/css/" />
<mvc:resources location="/js/**" mapping="/js/" />
<mvc:resources location="/images/**" mapping="/images/" />
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
    <property name="exceptionMappings">
        <props>
            <prop key="java.lang.Exception">error</prop>
        </props>
    </property>
</bean>
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
    <property name="prefix" value="/WEB-INF/views/" />
    <property name="suffix" value=".jsp" />
</bean>
<context:component-scan base-package="com.controllers" />
<context:property-placeholder location="classpath:application.properties"/>

PS：我已经将Jackson jar包括在我的课程中。

更新堆栈跟踪：

 02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl           (DistributionPlatformServiceImpl.java42) - Entering getPlatforms 
 02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl (DistributionPlatformRepositoryImpl.java40) - Entering getPlatforms
 02 Aug 2013 11:55:00 DEBUG impl.DistributionPlatformRepositoryImpl (DistributionPlatformServiceImpl.java88) - Entering getPlatformsAaData
 02 Aug 2013 11:55:00 DEBUG controllers.SearchPlatformController (SearchPlatformController.java56) - Grid Result is : {iTotalDisplayRecords=7, aaData=[[A, B, C, 7, D, E, C, In Active, 25], [A, T, B, 3, L, C, 001, In Active, 20]]}
 02 Aug 2013 11:55:00 DEBUG annotation.ExceptionHandlerExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
 02 Aug 2013 11:55:00 DEBUG annotation.ResponseStatusExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
 02 Aug 2013 11:55:00 DEBUG support.DefaultHandlerExceptionResolver (AbstractHandlerExceptionResolver.java132) - Resolving exception from handler [public java.util.Map<java.lang.String, java.lang.Object> com.controllers.SearchPlatformController.getPlatforms(com.model.form.SearchPlatformForm,org.springframework.ui.ModelMap)]: org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
 02 Aug 2013 11:55:00 DEBUG servlet.DispatcherServlet (DispatcherServlet.java999) - Null ModelAndView returned to DispatcherServlet with name 'managedaccounts': assuming HandlerAdapter completed request handling
 02 Aug 2013 11:55:00 DEBUG servlet.DispatcherServlet (FrameworkServlet.java951) - Successfully completed request

Answer 1

经过大量的搜索，我才能解决这个问题。一切都归功于Stackoverflow。请参考以下链接：

https://stackoverflow.com/a/13939290/1061430

基本上，以下部分需要包含在MVC配置文件中：

<mvc:annotation-driven content-negotiation-manager="contentNegotiationManager"/>
<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
<!-- Turn off working out content type based on URL file extension, should fall back to looking at the Accept headers -->
<property name="favorPathExtension" value="false" />
</bean>

再次感谢stackoverflow。

Answer 2

只需将杰克逊罐子包含在您的项目中，弹簧就会自动检测它的存在并使用它来序列化您的物体。

更新

我看到有人在没有澄清原因的情况下投了这个答案。这有点尴尬。特别是因为陈述是真的;）

所以这是一篇引自http://blog.springsource.org/2010/01/25/ajax-simplifications-in-spring-3-0/

的文章

在封面下，Spring MVC委托HttpMessageConverter执行序列化。在这种情况下，Spring MVC调用基于Jackson JSON处理器构建的MappingJacksonHttpMessageConverter。当您使用mvc：annotation-driven配置元素并且类路径中存在Jackson时，将自动启用此实现。

Answer 3

您使用的Jackson版本是什么？ Jackson 2.1.0适用于我的Spring 3.2以及下一个maven依赖项：

<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-core</artifactId>
  <version>2.1.0</version>
</dependency>
<dependency>
  <groupId>com.fasterxml.jackson.core</groupId>
  <artifactId>jackson-databind</artifactId>
  <version>2.1.0</version>
</dependency>

Spring MVC 3.2中的Json支持是否已损坏？

3 个答案:

更新