No converter found for return value of type xxx 异常解决

最近和同学共同搭建一套温控系统，出现了这样的一个问题，在本地调式没有问题，但是部署在 Linux 服务器上时却出现这样或那样的问题，环境兼容性不足，没有做好。例如我在部署 Linux 服务器的时候就是出现了 No converter found for return value of type: xxxx 的问题, 如下所示:

24-Oct-2017 17:42:23.495 严重 [http-nio-8080-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList] with root cause
 java.lang.IllegalArgumentException: No converter found for return value of type: class java.util.ArrayList
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:187)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:174)
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:81)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:113)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

项目环境

自己搭建的项目环境是：

1. Spring  4.3.14.RELEASE
2. Spring MVC 4.3.14.RELEASE
3. MyBatis 3.1.1
4. jdk  1.8
5. maven 3.2.5
6. tomcat 8.5

错误原因

相信很多的是同学都遇到过这样的问题，但是我还是头一次遇到过这样的问题，毕竟是自己从无到有，一点一点搭建的项目环境，很有可能是因为什么依赖包没有引入，导致出现一些问题呢, 最后经过问题分析, 原因是: Spring MVC默认是没有对象转换成JSON的转换器的，所以需要手动添加jackson依赖

所以在 pom 文件中进行查找相关依赖包，发现我的确是没有添加相关的依赖，所以对依赖包进行添加:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>${jackson.version}</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>${jackson.version}</version>
</dependency>

其中的 jackson.version 的版本是2.5.4, 然后再启动项目看是否还有问题。如果在添加了相对应的是依赖之后还是出现这个问题，那么再 spring mvc 的配置文件中进行以下的配置：

<!--spring mvc自动注解-->
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
            <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
        </mvc:message-converters>
    </mvc:annotation-driven>

上面配置的两个 bean 对象，一个是 SpringMVC 前端 JSON 转换器 MappingJackson2HttpMessageConverter , 这里需要注意的是，如果你使用的 spring 版本不同，配置是有不同， spring 3.x 和 spring 4.x 的类名是不一样的:

spring3.x是org.springframework.http.converter.json.MappingJacksonHttpMessageConverter

spring4.x是org.springframework.http.converter.json.MappingJackson2HttpMessageConverter

这里请根据项目中使用的 Spring 版本进行添加对应的 bean 对象。另外配置的 bean 对象是 StringHttpMessageConverter 一般是设置编码格式，如果向前台返回的中文出现乱码的问题，那么可以在这个 bean 对象中设置编码格式:

<bean class="org.springframework.http.converter.StringHttpMessageConverter">
    <property name="supportedMediaTypes">
        <list>
            <value>text/plain;charset=UTF-8</value>
        </list>
    /property>
</bean>