No converter found for return value of type解决方法

最近在学习SpringMVC过程中，项目在ajax与后台交互的时候，前台的ajax一直接收不到后台Controller返回来的包装类对象的json数据，spring版本为4.2.4，java对象和json对象转换一直报错：

java.lang.IllegalArgumentException: No converter found for return value of type: class cn.itcast.ssm.po.ItemsCustom    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:178)    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:153)    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:165)    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:80)    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:126)    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:121)    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2549)    at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2538)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)    at java.lang.Thread.run(Thread.java:744)

错误为没有该类型值的转换器，但是@responseBody注解会自动将返回数据封装成json格式，前台接收不到json对象，应该为json包版本冲突问题。
查看使用的json包为：

后来改为下面这三个json转换的jar包，

启动执行不报错，可以得到json格式的结果：

所以如果你也遇到了同样的问题，可以先检查一下是不是jar包不匹配的问题。

有需要jar包的小伙伴可以去下面地址下载：
http://download.csdn.net/download/qq_35917800/10105129