Fix Java.lang.IllegalArgumentException:No converter found for return value of Type:class java.util.ArrayList this issue

Today, using the SSM framework, with @responsebody annotations, this problem arises.

Java.lang.IllegalArgumentException:No Converter found for returnValue of type:classJava.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:132) 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:963) at Org.springframework.web.servlet.DispatcherServlet.doService (Dispatcherservlet.java:897) at Org.springframework.web.servlet.FrameworkServlet.processRequest (Frameworkservlet.java:970) at Org.springframework.web.servlet.FrameworkServlet.doPost (Frameworkservlet.java:872) at Javax.servlet.http.HttpServlet.service (Httpservlet.java:661) at Org.springframework.web.servlet.FrameworkServlet.service (Frameworkservlet.java:846) at Javax.servlet.http.HttpServlet.service (Httpservlet.java:742) at Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (Applicationfilterchain.java:231) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:166) at Org.apache.tomcat.websocket.server.WsFilter.doFilter (Wsfilter.java:52) at Org.apache.catalina.core.ApplicationFilterChain.internalDoFilter (Applicationfilterchain.java:193) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:166) 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:193) at Org.apache.catalina.core.ApplicationFilterChain.doFilter (Applicationfilterchain.java:166) at Org.apache.catalina.core.StandardWrapperValve.invoke (Standardwrappervalve.java:198) at Org.apache.catalina.core.StandardContextValve.invoke (Standardcontextvalve.java:96) at Org.apache.catalina.authenticator.AuthenticatorBase.invoke (Authenticatorbase.java:478) at Org.apache.catalina.core.StandardHostValve.invoke (Standardhostvalve.java:140) at Org.apache.catalina.valves.ErrorReportValve.invoke (Errorreportvalve.java:80) at Org.apache.catalina.valves.AbstractAccessLogValve.invoke (Abstractaccesslogvalve.java:624) at Org.apache.catalina.core.StandardEngineValve.invoke (Standardenginevalve.java:87) at Org.apache.catalina.connector.CoyoteAdapter.service (Coyoteadapter.java:342) at Org.apache.coyote.http11.Http11Processor.service (Http11processor.java:799) at Org.apache.coyote.AbstractProcessorLight.process (Abstractprocessorlight.java:66) at Org.apache.coyote.abstractprotocol$connectionhandler.process (Abstractprotocol.java:861) at Org.apache.tomcat.util.net.nioendpoint$socketprocessor.dorun (Nioendpoint.java:1455) 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:748)

This is because SPRINGMVC default is no object converted to JSON converter, we need to configure other converters, here I used Ali's Fastjson

First introduce the Fastjson jar package

Then configure it in the SPRINGMVC configuration file

　

<!--Configuring note Drivers -    <Mvc:annotation-driven>        <mvc:message-convertersRegister-defaults= "false">            <Beanclass= "Org.springframework.http.converter.StringHttpMessageConverter"/>            <Beanclass= "Org.springframework.http.converter.xml.XmlAwareFormHttpMessageConverter"/>            <Beanclass= "Org.springframework.http.converter.ByteArrayHttpMessageConverter"/>            <Beanclass= "Org.springframework.http.converter.BufferedImageHttpMessageConverter"/>            <!--Configuring Fastjson Support -            <BeanID= "Fastjsonhttpmessageconverter"class= "Com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">                < Propertyname= "Supportedmediatypes">                    <List>                        <value>Text/html;charset=utf-8</value>                        <value>Application/json;charset=utf-8</value>                    </List>                </ Property>            </Bean>        </mvc:message-converters>    </Mvc:annotation-driven>

After restarting the server, the problem is resolved after running

Fix Java.lang.IllegalArgumentException:No converter found for return value of Type:class java.util.ArrayList this issue