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巧用arthas 分析 java.lang.reflect.UndeclaredThrowableException 异常来源
背景
使用了https://square.github.io/retrofit/ 包装接口，响应值不正常的时候抛出一个异常堆栈 异常堆栈从哪里来的？不应该是 com.fasterxml.jackson.core.JsonParseException 异常？ 怎么会被包装成了 java.lang.reflect.UndeclaredThrowableException
java.lang.reflect.UndeclaredThrowableException
at com.sun.proxy.$Proxy60.tokenAuth(Unknown Source)
at com.example.controller.AccountTestController.auth(AccountTestController.java:114)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1072)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:965)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:502)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:596)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:209)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:178)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:153)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:492)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:389)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:926)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1791)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'ok': was expecting (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
at [Source: (okhttp3.ResponseBody$BomAwareReader); line: 1, column: 3]
at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:2391)
at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:745)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._reportInvalidToken(ReaderBasedJsonParser.java:2961)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._handleOddValue(ReaderBasedJsonParser.java:2002)
at com.fasterxml.jackson.core.json.ReaderBasedJsonParser.nextToken(ReaderBasedJsonParser.java:802)
at com.fasterxml.jackson.databind.ObjectReader._initForReading(ObjectReader.java:356)
at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2041)
at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1459)
at retrofit2.converter.jackson.JacksonResponseBodyConverter.convert(JacksonResponseBodyConverter.java:33)
at retrofit2.converter.jackson.JacksonResponseBodyConverter.convert(JacksonResponseBodyConverter.java:23)
at retrofit2.OkHttpCall.parseResponse(OkHttpCall.java:243)
at retrofit2.OkHttpCall.execute(OkHttpCall.java:204)
探索思路
模拟不正常的响应值导致反序列化失败.. 自己写一个mock 服务,eg 返回对象 返回一个string
断点跟踪
JacksonResponseBodyConverter.convert 确实是 抛出了一个异常 com.fasterxml.jackson.core.JsonParseException,之后就没有之后了.. 这个方法不可行,这里面临一个问题，由于动态代理的代码是动态生成的没办法进行调试。
java.lang.reflect.UndeclaredThrowableException retrofit 内部哪里有使用
根据推断 内部只有一个地方使用，设置断点发现没有调用实例进入.. 发现这个思路走错了..
突破口 "动态代理“
at com.sun.proxy.$Proxy60.tokenAuth(Unknown Source) Unknown Source ? 利用工具反编译查看一下源码ok？ arthas jad command
curl -L "https://arthas.aliyun.com/as.sh" >as.sh; chmod a+x as.sh; ./as.sh 安装arthas 执行命令 jad com.sun.proxy.$Proxy60 tokenAuth
反编译的结果
public final BaseResponse tokenAuth(AccountContextAccountContext,TokenAuthRequestTokenAuthRequest) {
try {
return (BaseResponse)this.h.invoke(this, m5, new Object[]{AccountContext,TokenAuthRequest});
}
catch (Error | RuntimeException throwable) {
throw throwable;
}
catch (Throwable throwable) {
throw new UndeclaredThrowableException(throwable);
}
}
原来是动态代理这里进行了包装处理了RuntimeException 原样返回,Throwable 会进行包装
查询了一下相关bolg java.lang.reflect.UndeclaredThrowableException的解决 基本上就是动态代理的问题
总结
通过对于异常的深入探究，跟踪了解到了实现原理, “工欲善其事，必先利其器"
