Feign 報異常IOException Incomplete output stream

來源：https://www.jianshu.com/p/6397e2cd1fae

@FeignClient("cc-task")
public interface ICallCenterTaskService {

    @RequestMapping(value="/cc/v1/task/enterprises/{enterprise_id}/tasks",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_VALUE)
    PostTaskResponseParam createCcCallTask(    @PathVariable("enterprise_id") String tenantId,String postTaskRequestParam);

@RequestMapping(value="/cc/v1/task/enterprises/{enterprise_id}/tasks",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_VALUE)
PostTaskResponseParam createCcCallTask(@PathVariable("enterprise_id") String tenantId, PostTaskRequestParam postTaskRequestParam);

 

 

今天在做一個從Feign客戶端到service服務端的POST請求，service服務端Controller類中方法測試正常，但卻在Feign客戶端返回時報錯，錯誤信息如下：

Caused by: feign.RetryableException: Incomplete output stream executing POST http://服務名/路徑/方法名 at feign.FeignException.errorExecuting(FeignException.java:67) at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:104) at ............異常太多省略........... Caused by: java.io.IOException: Incomplete output stream at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1523) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492) at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480) at feign.Client$Default.convertResponse(Client.java:152) at feign.Client$Default.execute(Client.java:74) at org.springframework.cloud.sleuth.instrument.web.client.feign.TracingFeignClient.execute(TracingFeignClient.java:88) at org.springframework.cloud.sleuth.instrument.web.client.feign.LazyTracingFeignClient.execute(LazyTracingFeignClient.java:54) at org.springframework.cloud.openfeign.ribbon.FeignLoadBalancer.execute(FeignLoadBalancer.java:89) at org.springframework.cloud.openfeign.ribbon.FeignLoadBalancer.execute(FeignLoadBalancer.java:55) at com.netflix.client.AbstractLoadBalancerAwareClient$1.call(AbstractLoadBalancerAwareClient.java:104) at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:303) at com.netflix.loadbalancer.reactive.LoadBalancerCommand$3$1.call(LoadBalancerCommand.java:287) at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:231) at rx.internal.util.ScalarSynchronousObservable$3.call(ScalarSynchronousObservable.java:228) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.drain(OnSubscribeConcatMap.java:286) at rx.internal.operators.OnSubscribeConcatMap$ConcatMapSubscriber.onNext(OnSubscribeConcatMap.java:144) at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:185) at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber$1.call(OperatorRetryWithPredicate.java:127) at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) at rx.Subscriber.setProducer(Subscriber.java:209) at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.subscribe(Observable.java:10423) at rx.Observable.subscribe(Observable.java:10390) at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:443) at rx.observables.BlockingObservable.single(BlockingObservable.java:340) at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:112) at org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:63) at org.springframework.cloud.sleuth.instrument.web.client.feign.TraceLoadBalancerFeignClient.access$001(TraceLoadBalancerFeignClient.java:36) at org.springframework.cloud.sleuth.instrument.web.client.feign.TraceLoadBalancerFeignClient.lambda$execute$0(TraceLoadBalancerFeignClient.java:50) at org.springframework.cloud.sleuth.instrument.web.client.feign.TracingFeignClient.execute(TracingFeignClient.java:88) at org.springframework.cloud.sleuth.instrument.web.client.feign.LazyTracingFeignClient.execute(LazyTracingFeignClient.java:54) at org.springframework.cloud.sleuth.instrument.web.client.feign.TraceLoadBalancerFeignClient.execute(TraceLoadBalancerFeignClient.java:50) at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:97) ... 77 common frames omitted 

心想居然IO異常啦，但service端能正確返回數據啊，所以故障先鎖定在Feign客戶端服務上。根據異常調用鏈得知最終發生車禍的是sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1523) HttpURLConnection.getInputStream0方法1523行。經過搜索資料，原來feign采用jdk原生HttpURLConnection向下游服務發起http請求（源碼詳見feign.Client.Default），先到getInputStream0方法看看：

    private synchronized InputStream getInputStream0() throws IOException { if(!this.doInput) { throw new ProtocolException("Cannot read from URLConnection if doInput=false (call setDoInput(true))"); } else if(this.rememberedException != null) { if(this.rememberedException instanceof RuntimeException) { throw new RuntimeException(this.rememberedException); } else { throw this.getChainedException((IOException)this.rememberedException); } } else if(this.inputStream != null) { return this.inputStream; } else { if(this.streaming()) { if(this.strOutputStream == null) { this.getOutputStream(); } this.strOutputStream.close(); if(!this.strOutputStream.writtenOK()) { throw new IOException("Incomplete output stream"); // 1523行 } }.......... // this.strOutputStream.writtenOK()方法 boolean writtenOK() { return this.closed && !this.error; } 

看起來，this.error是true導致的，也就是說在OutputStream寫入流時出錯。

沒辦法，只能用Apache HttpClient替換掉原生HttpURLConnection。加入依賴：

<!-- 使用Apache HttpClient替換Feign原生httpclient --> <!-- feign-httpclient內含Apache HttpClient --> <dependency> <groupId>com.netflix.feign</groupId> <artifactId>feign-httpclient</artifactId> <version>8.17.0</version> </dependency> 

然后在application.yml中添加如下：

feign:
  httpclient:
    enabled: true 

重新調用，一切恢復正常。噢耶！

另外補充一點：
引入Apache HttpClient包時，需要注意指定Content-Type，不然會產生以下異常：

Caused by: java.lang.IllegalArgumentException: MIME type may not contain reserved characters 

解決辦法 ：

@RequestMapping(value = "/getUser", method = RequestMethod.GET, consumes = MediaType.APPLICATION_JSON_VALUE) 

注解中指定： Content-Type 即 指定 consumes 的屬性值

作者：martin6699
鏈接：https://www.jianshu.com/p/6397e2cd1fae
來源：簡書
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