当我为 json 添加配置时，Spring MVC 应用程序中断答案

【问题标题】：Spring MVC app breaks when I add config for json当我为 json 添加配置时，Spring MVC 应用程序中断
【发布时间】：2015-10-16 21:29:43
【问题描述】：

当我将这段代码添加到我的 servlet-config.xml 时，它会破坏我的 Spring MVC 应用程序。我过去曾因错误的版本依赖关系而遇到麻烦，所以我想知道这是否是问题所在。

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="order" value="1" />
<property name="contentNegotiationManager">
    <bean class="org.springframework.web.accept.ContentNegotiationManager">
        <constructor-arg>
            <bean class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
                <constructor-arg>
                    <map>
                        <entry key="json" value="application/json" />
                        <entry key="xml" value="application/xml" />
                    </map>
                </constructor-arg>
            </bean>
        </constructor-arg>
    </bean>
</property>

<property name="defaultViews">
    <list>
        <bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
        <bean class="org.springframework.web.servlet.view.xml.MarshallingView">
            <constructor-arg>
                <bean class="org.springframework.oxm.xstream.XStreamMarshaller">
                    <property name="autodetectAnnotations" value="true" />
                </bean>
            </constructor-arg>
        </bean>
    </list>
</property> </bean>

这是我的 servlet-config.xml，在我尝试添加上面的片段来处理 json 之前它可以工作。

<?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"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.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-3.2.xsd">

    <mvc:annotation-driven/>

    <mvc:resources location="pdfs" mapping="/pdfs/**"/>

    <context:component-scan base-package="com.pluralsight"/>

    <mvc:interceptors>
        <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" p:paramName="language"/>
    </mvc:interceptors>

    <bean id="localeResolver" class="org.springframework.web.servlet.i18n.SessionLocaleResolver" p:defaultLocale="en"/>

    <bean id="messageSource" 
    class="org.springframework.context.support.ResourceBundleMessageSource" 
    p:basename="messages"></bean>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" 
     p:prefix="/WEB-INF/jsp/" p:suffix=".jsp" p:order="2"/>

     <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" p:order="0"/>

</beans>

这是我的 web.xml

<?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>fitTrackerServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/config/servlet-config.xml</param-value>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>fitTrackerServlet</servlet-name>
        <url-pattern>*.html</url-pattern>
    </servlet-mapping>

    <servlet-mapping>
        <servlet-name>fitTrackerServlet</servlet-name>
        <url-pattern>/pdfs/**</url-pattern>
    </servlet-mapping>

        <servlet-mapping>
        <servlet-name>fitTrackerServlet</servlet-name>
        <url-pattern>*.json</url-pattern>
    </servlet-mapping>

    <display-name>Archetype Created Web Application</display-name>
</web-app>

这是我的 pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.pluralsight</groupId>
  <artifactId>FitnessTracker</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>FitnessTracker Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.1.1.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>4.3.1.Final</version>
    </dependency>
    <dependency>
        <groupId>javax.validation</groupId>
        <artifactId>validation-api</artifactId>
        <version>1.0.0.GA</version>
    </dependency>
        <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.4.1</version>
    </dependency>
    <dependency>
        <groupId>com.thoughtworks.xstream</groupId>
        <artifactId>xstream</artifactId>
        <version>1.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-oxm</artifactId>
        <version>3.2.0.RELEASE</version>
    </dependency>
  </dependencies>
  <build>
    <finalName>FitnessTracker</finalName>
  </build>
</project>

错误是：

root cause

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.view.ContentNegotiatingViewResolver#0' defined in ServletContext resource [/WEB-INF/config/servlet-config.xml]: Cannot create inner bean 'org.springframework.web.servlet.view.json.MappingJacksonJsonView#a01c402' of type [org.springframework.web.servlet.view.json.MappingJacksonJsonView] while setting bean property 'defaultViews' with key [0]; nested exception is org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [org.springframework.web.servlet.view.json.MappingJacksonJsonView] for bean with name 'org.springframework.web.servlet.view.json.MappingJacksonJsonView#a01c402' defined in ServletContext resource [/WEB-INF/config/servlet-config.xml]; nested exception is java.lang.ClassNotFoundException: org.springframework.web.servlet.view.json.MappingJacksonJsonView
    org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:290)
    org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:122)
    org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:359)
    org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:157)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1471)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1216)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229)
    org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:725)
    org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:663)
    org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:629)
    org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:677)
    org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:548)
    org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:489)
    org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    javax.servlet.GenericServlet.init(GenericServlet.java:160)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    java.lang.Thread.run(Unknown Source)

【问题讨论】：

你得到的错误信息是什么？
刚刚发布错误，谢谢。

标签： java spring maven spring-mvc

【解决方案1】：

对于 Spring 框架 4.1.x，您使用的是 Jackson2，而不是 Jackson1。

请尝试更换

MappingJacksonJsonView

到

MappingJackson2JsonView

【讨论】：

谢谢，这让我走上了正轨。我还需要添加： com.fasterxml.jackson.corejackson-databind2.3.2 到我的 pom .xml 然后它就起作用了。
然后 bean 看起来像：<bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"> <property name="contentType" value="application/json"/> </bean>
但是如果我添加 com.fasterxml.jackson.core 作为依赖项，tomcat 服务器就会停止。有什么问题？

【解决方案2】：

从@Dust Francis 添加解决方案但我得到了一些错误但是将 Spring 框架（spring-mvc 和 spring-oxm）更改为相同版本为我解决了这个问题。 pom.xml 看起来像

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.navroop</groupId>
  <artifactId>FitnessTracker</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>FitnessTracker Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.1.9.RELEASE</version>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-oxm</artifactId>
      <version>5.1.9.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-validator</artifactId>
      <version>6.1.0.Alpha6</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.10.0.pr1</version>
    </dependency>
    <dependency>
      <groupId>org.codehaus.jackson</groupId>
      <artifactId>jackson-mapper-asl</artifactId>
      <version>1.9.13</version>
    </dependency>
    <dependency>
      <groupId>com.thoughtworks.xstream</groupId>
      <artifactId>xstream</artifactId>
      <version>1.4.11.1</version>
    </dependency>
  </dependencies>
  <build>
    <finalName>FitnessTracker</finalName>
  </build>
</project>

【讨论】：