大家好，我是烤鸭：
dubbo遇到如下问题。
某个异常对象无法实例化。
com.alibaba.dubbo.rpc.RpcException: Failed to invoke remote method: updateCardBycustomerNum, provider: dubbo://20.x.xx.48:20883/com.etc.service.bank.EtcBankcardInfoService?anyhost=true&application=etc_manage_web&check=false&default.timeout=600000&dubbo=2.6.2&generic=false&interface=com.etc.service.bank.EtcBankcardInfoService&methods=protocolBindCardSupplement,queryAlipayBinds,update,insert,updateCardBycustomerNum,bindAlipay,getUserByCustomerNum,selectListByObject,validateBindCard,updateDefault,selectBycustomerNum,validateBindCardSupplement,protocolBindCard,selectOneByObject,selectBycustomerNumBackend&pid=2539®ister.ip=10.xx.xx.47&remote.timestamp=1561084612315&revision=1.0-SNAPSHOT&side=consumer×tamp=1561101150616, cause: com.alibaba.com.caucho.hessian.io.HessianFieldException: org.apache.http.conn.HttpHostConnectException.host: 'org.apache.http.HttpHost' could not be instantiated com.alibaba.com.caucho.hessian.io.HessianFieldException: org.apache.http.conn.HttpHostConnectException.host: 'org.apache.http.HttpHost' could not be instantiated at com.alibaba.com.caucho.hessian.io.JavaDeserializer.logDeserializeError(JavaDeserializer.java:167) at com.alibaba.com.caucho.hessian.io.JavaDeserializer$ObjectFieldDeserializer.deserialize(JavaDeserializer.java:412) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:276) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:203) at com.alibaba.com.caucho.hessian.io.SerializerFactory.readObject(SerializerFactory.java:526) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObjectInstance(Hessian2Input.java:2810) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2750) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2279) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2724) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2279) at com.alibaba.dubbo.common.serialize.hessian2.Hessian2ObjectInput.readObject(Hessian2ObjectInput.java:84) at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:92) at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:113) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCodec.decodeBody(DubboCodec.java:89) at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:124) at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:84) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCountCodec.decode(DubboCountCodec.java:46) at com.alibaba.dubbo.remoting.transport.netty.NettyCodecAdapter$InternalDecoder.messageReceived(NettyCodecAdapter.java:133) at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:80) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261) at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:349) at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:280) at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:200) at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:44) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: com.alibaba.com.caucho.hessian.io.HessianProtocolException: 'org.apache.http.HttpHost' could not be instantiated at com.alibaba.com.caucho.hessian.io.JavaDeserializer.instantiate(JavaDeserializer.java:316) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:201) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObjectInstance(Hessian2Input.java:2808) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2146) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2075) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2119) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2075) at com.alibaba.com.caucho.hessian.io.JavaDeserializer$ObjectFieldDeserializer.deserialize(JavaDeserializer.java:408) ... 29 more Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedConstructorAccessor90.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.instantiate(JavaDeserializer.java:312) ... 36 more Caused by: java.lang.IllegalArgumentException: Host name may not be null at org.apache.http.util.Args.containsNoBlanks(Args.java:81) at org.apache.http.HttpHost.<init>(HttpHost.java:80) at org.apache.http.HttpHost.<init>(HttpHost.java:135) ... 40 more at com.alibaba.dubbo.rpc.protocol.dubbo.DubboInvoker.doInvoke(DubboInvoker.java:100) at com.alibaba.dubbo.rpc.protocol.AbstractInvoker.invoke(AbstractInvoker.java:148) at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:75) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72) at com.alibaba.dubbo.rpc.protocol.dubbo.filter.FutureFilter.invoke(FutureFilter.java:54) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72) at com.alibaba.dubbo.rpc.filter.ConsumerContextFilter.invoke(ConsumerContextFilter.java:48) at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72) at com.alibaba.dubbo.rpc.listener.ListenerInvokerWrapper.invoke(ListenerInvokerWrapper.java:77) at com.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:56) at com.alibaba.dubbo.rpc.cluster.support.FailoverClusterInvoker.doInvoke(FailoverClusterInvoker.java:78) at com.alibaba.dubbo.rpc.cluster.support.AbstractClusterInvoker.invoke(AbstractClusterInvoker.java:238) at com.alibaba.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker.invoke(MockClusterInvoker.java:75) at com.alibaba.dubbo.rpc.proxy.InvokerInvocationHandler.invoke(InvokerInvocationHandler.java:52) at com.alibaba.dubbo.common.bytecode.proxy5.updateCardBycustomerNum(proxy5.java) at com.etc.controller.bank.EtcBankcardInfoController.findUserCard(EtcBankcardInfoController.java:334) at sun.reflect.GeneratedMethodAccessor301.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.etc.controller.util.InvokeController.invoke(InvokeController.java:88) at sun.reflect.GeneratedMethodAccessor197.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) 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.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61) at com.etc.filter.CookieFilter.doFilter(CookieFilter.java:30) at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66) at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449) at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365) at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90) at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83) at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383) at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362) at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125) 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.CorsFilter.doFilterInternal(CorsFilter.java:96) 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.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) 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.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) 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.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) 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.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) 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:493) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) 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:800) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: com.alibaba.dubbo.remoting.RemotingException: com.alibaba.com.caucho.hessian.io.HessianFieldException: org.apache.http.conn.HttpHostConnectException.host: 'org.apache.http.HttpHost' could not be instantiated com.alibaba.com.caucho.hessian.io.HessianFieldException: org.apache.http.conn.HttpHostConnectException.host: 'org.apache.http.HttpHost' could not be instantiated at com.alibaba.com.caucho.hessian.io.JavaDeserializer.logDeserializeError(JavaDeserializer.java:167) at com.alibaba.com.caucho.hessian.io.JavaDeserializer$ObjectFieldDeserializer.deserialize(JavaDeserializer.java:412) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:276) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:203) at com.alibaba.com.caucho.hessian.io.SerializerFactory.readObject(SerializerFactory.java:526) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObjectInstance(Hessian2Input.java:2810) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2750) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2279) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2724) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2279) at com.alibaba.dubbo.common.serialize.hessian2.Hessian2ObjectInput.readObject(Hessian2ObjectInput.java:84) at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:92) at com.alibaba.dubbo.rpc.protocol.dubbo.DecodeableRpcResult.decode(DecodeableRpcResult.java:113) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCodec.decodeBody(DubboCodec.java:89) at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:124) at com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec.decode(ExchangeCodec.java:84) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboCountCodec.decode(DubboCountCodec.java:46) at com.alibaba.dubbo.remoting.transport.netty.NettyCodecAdapter$InternalDecoder.messageReceived(NettyCodecAdapter.java:133) at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:80) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564) at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:274) at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:261) at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:349) at org.jboss.netty.channel.socket.nio.NioWorker.processSelectedKeys(NioWorker.java:280) at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:200) at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108) at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:44) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: com.alibaba.com.caucho.hessian.io.HessianProtocolException: 'org.apache.http.HttpHost' could not be instantiated at com.alibaba.com.caucho.hessian.io.JavaDeserializer.instantiate(JavaDeserializer.java:316) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.readObject(JavaDeserializer.java:201) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObjectInstance(Hessian2Input.java:2808) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2146) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2075) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2119) at com.alibaba.com.caucho.hessian.io.Hessian2Input.readObject(Hessian2Input.java:2075) at com.alibaba.com.caucho.hessian.io.JavaDeserializer$ObjectFieldDeserializer.deserialize(JavaDeserializer.java:408) ... 29 more Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedConstructorAccessor90.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at com.alibaba.com.caucho.hessian.io.JavaDeserializer.instantiate(JavaDeserializer.java:312) ... 36 more Caused by: java.lang.IllegalArgumentException: Host name may not be null at org.apache.http.util.Args.containsNoBlanks(Args.java:81) at org.apache.http.HttpHost.<init>(HttpHost.java:80) at org.apache.http.HttpHost.<init>(HttpHost.java:135) ... 40 more at com.alibaba.dubbo.remoting.exchange.support.DefaultFuture.returnFromResponse(DefaultFuture.java:222) at com.alibaba.dubbo.remoting.exchange.support.DefaultFuture.get(DefaultFuture.java:139) at com.alibaba.dubbo.remoting.exchange.support.DefaultFuture.get(DefaultFuture.java:112) at com.alibaba.dubbo.rpc.protocol.dubbo.DubboInvoker.doInvoke(DubboInvoker.java:95) ... 88 more猜测可能是内网调用，没有配置hostname 导致的。
1. 查看机器名
hostname2.修改hosts文件 ,如果前面机器名已被映射我们就将其注释掉
vi /etc/hosts ip hostname #比如 hostname 为 aaa,ip 为 11.22.33.123 11.22.33.123 aaa3. 刷新hosts文件
source /etc/hosts4.重启网卡
systemctl restart network后来又仔细检查一遍日志发现一个问题。我们是采用多个提供者的模式，可能相同的消费者指向了不同的提供者。其实多个提供者也不会有这个问题，分别去 47 和 48 服务器看了，发现两个服务器的 jar包大小不一样，说明两个包的版本不一致。
这次出现的问题就是这样了。具体的原因还没有查，如果有类似的问题，可以参考下我这个场景。
如果是自定义的包或者类，可能是没有默认的构造器之类的问题，加上就好了。
