feign.codec.EncodeException: class java.util.ArrayList is not a type supported by this encoder

Posted 2022-04-09 Murphy's cool

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问题背景

在springcloud 盛行的今天 , 我们无可避免的要面对服务间的调用 . 最常用的就是feign client 这种方式进行服务之间调用了.

在疫情紧张的某一天. 我需要使用feign client开发一个接口, 这个接口是post 请求, 参数是一个VO 对象. 于是乎我定义接口如下.
//发生异常的接口
@FeignClient(name = DeviceServiceName.SERVICE_NAME, fallbackFactory = DemoClient.DemoClientFallback.class)
public interface DemoService    
    @PostMapping(value = "/adm/device/post/demo",consumes = MediaType.APPLICATION_JSON_VALUE)
    public R<Device> postDevice(@RequestBody  Device device) ;
当我定义完后,屁颠屁颠就开始调式了. 不开心的事情终究还是发生了. 嗝屁了.尴尬.报了下面的错误

错误

2020-04-27 14:19:41,086 ERROR [http-nio-8008-exec-2] org.skywayframework.common.handler.GlobalExceptionHandler : [SEI-ERROR] System exception, unknown error! message is : class java.util.ArrayList is not a type supported by this encoder. !
feign.codec.EncodeException: class java.util.ArrayList is not a type supported by this encoder.
	at feign.codec.Encoder$Default.encode(Encoder.java:94) ~[feign-core-10.1.0.jar:na]
	at feign.form.FormEncoder.encode(FormEncoder.java:90) ~[feign-form-3.8.0.jar:na]
	at feign.form.spring.SpringFormEncoder.encode(SpringFormEncoder.java:64) ~[feign-form-spring-3.5.0.jar:na]
	at feign.ReflectiveFeign$BuildEncodedTemplateFromArgs.resolve(ReflectiveFeign.java:372) ~[feign-core-10.1.0.jar:na]
	at feign.ReflectiveFeign$BuildTemplateByResolvingArgs.create(ReflectiveFeign.java:224) ~[feign-core-10.1.0.jar:na]
	at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:74) ~[feign-core-10.1.0.jar:na]
	at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:103) ~[feign-core-10.1.0.jar:na]
	at com.sun.proxy.$Proxy183.postListDevice(Unknown Source) ~[na:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:100) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.common.config.RequestAspect.doAround(RequestAspect.java:128) ~[classes/:na]
	at org.skywayframework.common.config.RequestAspect.postMappingDoAround(RequestAspect.java:68) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at com.sun.proxy.$Proxy184.postListDevice(Unknown Source) ~[na:na]
	at org.skywayframework.system.controller.AdminDemoController.postListDemo(AdminDemoController.java:50) ~[classes/:na]
	at org.skywayframework.system.controller.AdminDemoController$$FastClassBySpringCGLIB$$10b091d3.invoke(<generated>) ~[classes/:na]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:100) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.common.config.RequestAspect.doAround(RequestAspect.java:128) ~[classes/:na]
	at org.skywayframework.common.config.RequestAspect.postMappingDoAround(RequestAspect.java:68) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.system.controller.AdminDemoController$$EnhancerBySpringCGLIB$$c48246a5.postListDemo(<generated>) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189) ~[spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.github.xiaoymin.knife4j.spring.filter.ProductionSecurityFilter.doFilter(ProductionSecurityFilter.java:53) [knife4j-spring-2.0.2.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.github.xiaoymin.knife4j.spring.filter.SecurityBasicAuthFilter.doFilter(SecurityBasicAuthFilter.java:90) [knife4j-spring-2.0.2.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) [druid-1.1.10.jar:1.1.10]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.cloud.sleuth.instrument.web.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.java:50) [spring-cloud-sleuth-core-2.1.0.RELEASE.jar:2.1.0.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at brave.servlet.TracingFilter.doFilter(TracingFilter.java:86) [brave-instrumentation-servlet-5.6.1.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]
2020-04-27 14:19:41,121 INFO  [http-nio-8008-exec-2] org.skywayframework.common.interceptor.RequestParamInterceptor : [SEI-DEBUG] POST :  the url is /demo/device/post2 !

或者错误

"code": 65500,
  "message": "Error while extracting response for type [com.seirobotics.framework.model.ResponseData<java.util.List<com.seirobotics.content.api.entity.request.recommend.RecommendGroupVo>>] and content type [application/json;charset=UTF-8]; nested exception is org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance of `java.util.ArrayList` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList` out of START_OBJECT token\\n at [Source: (PushbackInputStream); line: 1, column: 158] (through reference chain: com.seirobotics.framework.model.ResponseData[\\"body\\"])",

我使用的技术栈如下

Springboot 2.1.2.RELEASE

SpringCloud Greenwich.RELEASE

OpenFeign 2.1.0RELEASE

错误原因分析

老规矩,首先看看feign 中默认的Jackson Encoder

package feign.jackson;

public class JacksonEncoder implements Encoder 
    private final ObjectMapper mapper;

    public JacksonEncoder() 
        this((Iterable)Collections.emptyList());
    

    public JacksonEncoder(Iterable<Module> modules) 
        this((new ObjectMapper()).setSerializationInclusion(Include.NON_NULL).configure(SerializationFeature.INDENT_OUTPUT, true).registerModules(modules));
    

    public JacksonEncoder(ObjectMapper mapper) 
        this.mapper = mapper;
    

    public void encode(Object object, Type bodyType, RequestTemplate template) 
        try 
            JavaType javaType = this.mapper.getTypeFactory().constructType(bodyType);
            template.body(this.mapper.writerFor(javaType).writeValueAsString(object));
         catch (JsonProcessingException var5) 
            throw new EncodeException(var5.getMessage(), var5);

核心的encoder方法就是在服务调用的时候进行解码. 自定义类型它无法识别. 它并不能识别我们自定义的Device 类!!!

通过stack overflow 查一下相关问题 , 链接 How to POST form-url-encoded data with Spring Cloud Feign

分析出原因需要自定义解码器. 好了. 问题找到了 ,开始行动吧

解决办法

1.client 接口定义需要指定一个configuration ,告诉client 使用哪一个encoder

2.声明一个feignFormEncoder, 并声明为spring中的一个Bean

源代码如下:

@FeignClient(name = DeviceServiceName.SERVICE_NAME, fallbackFactory = DemoClient.DemoClientFallback.class,configuration = DemoClient.Configuration.class)
public interface DemoService 

    @PostMapping(value = "/adm/device/post/demo",consumes = MediaType.APPLICATION_JSON_VALUE)
    public R<Device> postDevice(@RequestBody  Device device) ;

    class Configuration 

        @Bean
        Encoder feignFormEncoder(ObjectFactory<HttpMessageConverters> converters) 
            return new SpringFormEncoder(new SpringEncoder(converters));

验证问题是否解决

PS: 再次尝试发送同样的请求, 服务之间调用没有再报异常 . 得到如下结果


	"code": 0,
	"message": "success",
	"signature": "61111c7a7fbb407b9eb00bdb559e1774",
	"requestId": "61111c7a7fbb407b9eb00bdb559e1774",
	"timestamp": 1587969336934,
	"body": 
		"count": 2,
		"size": 0,
		"current": 0,
		"data": [
			"devId": null,
			"model": "model",
			"sn": null,
			"ethMac": null,
			"wifiMac": null,
			"cpu": "cpu-demo",
			"internalStorage": null,
			"ram": null,
			"vcId": null
		, 
			"devId": null,
			"model": "mode2",
			"sn": null,
			"ethMac": null,
			"wifiMac": null,
			"cpu": "cpu-demo2",
			"internalStorage": null,
			"ram": null,
			"vcId": null
		]
	
 
	"tenantCode": "SEI110D000000000094",
	"apkInfoList": [
		"apkPackage": "",
		"apkVersion": ""
	]

问题得到解决!!! 你就可以愉快地使用Feign 传递自定义对象, 或者List<T> 这种类型的参数啦.美滋滋!!!

当然,这个configuration 可以声明在一个公共的地方, 所有的client 都可以共享啦 .滴 ,打卡下班

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