背景
今天下午遇到同事求助，說是服務端出現了好幾個java.io.IOException: Broken pipe這樣的異常，讓我幫忙看一下，這個問題對於我們做服務端開發的技術人員是很容易遇到的，特此記錄一下。
探究
問題堆棧
org.apache.catalina.connector.ClientAbortException: java.io.IOException: Broken pipe at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:356) at org.apache.catalina.connector.OutputBuffer.flushByteBuffer(OutputBuffer.java:825) at org.apache.catalina.connector.OutputBuffer.append(OutputBuffer.java:730) at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:391) at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:369) at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:96) at org.springframework.session.web.http.OnCommittedResponseWrapper$SaveContextServletOutputStream.write( OnCommittedResponseWrapper.java:620) at org.springframework.security.web.util.OnCommittedResponseWrapper$SaveContextServletOutputStream.write( OnCommittedResponseWrapper.java:639) at org.springframework.security.web.util.OnCommittedResponseWrapper$SaveContextServletOutputStream.write( OnCommittedResponseWrapper.java:639) at com.fasterxml.jackson.core.json.UTF8JsonGenerator._flushBuffer(UTF8JsonGenerator.java:2085) at com.fasterxml.jackson.core.json.UTF8JsonGenerator._writeBytes(UTF8JsonGenerator.java:1173) at com.fasterxml.jackson.core.json.UTF8JsonGenerator.writeFieldName(UTF8JsonGenerator.java:256) at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:725) at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:119) at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:79) at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serialize(IndexedListSerializer.java:18) at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480) at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319) at com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize(ObjectWriter.java:1396) at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:913) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal( AbstractJackson2HttpMessageConverter.java:286) at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:102) at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters( AbstractMessageConverterMethodProcessor.java:272) at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue( RequestResponseBodyMethodProcessor.java:180) at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue( HandlerMethodReturnValueHandlerComposite.java:82) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle( ServletInvocableHandlerMethod.java:119) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod( RequestMappingHandlerAdapter.java:877) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal( RequestMappingHandlerAdapter.java:783) 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:707) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) 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)
着重關注點
堆棧信息中有一行比較關鍵，在OutputBuffer :: realWriteBytes這個方法中出現了異常，在方法內部拋出了ClientAbortException：
at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:356)
OutputBuffer#realWriteBytes
/**
* Sends the buffer data to the client output, checking the
* state of Response and calling the right interceptors.
*
* @param buf the ByteBuffer to be written to the response
*
* @throws IOException An underlying IOException occurred
*/
public void realWriteBytes(ByteBuffer buf) throws IOException {
if (closed) {
return;
}
if (coyoteResponse == null) {
return;
}
// If we really have something to write
if (buf.remaining() > 0) {
// real write to the adapter
try {
coyoteResponse.doWrite(buf);
} catch (IOException e) {
// An IOException on a write is almost always due to
// the remote client aborting the request. Wrap this
// so that it can be handled better by the error dispatcher.
throw new ClientAbortException(e);
}
}
}
在上面的代碼中，調用coyoteResponse.doWrite(buf);方法時，會拋出ClientAbortException異常
我們仔細閱讀以下上述注釋：
An IOException on a write is almost always due to the remote client aborting the request. Wrap this so that it can be handled better by the error dispatcher. 進行寫操作時出現的IOException幾乎總是由於遠程客戶端中止請求而導致的。將其包裝起來，以便錯誤調度程序可以更好地處理它。
結論
有位大神將此問題對應的流程圖畫的很好，特摘錄過來：秋夜無霜
如上圖：
調用方通過restTemplate封裝的http連接池，這時候連接設置connectTimeout=3000,readTimeout=3000，然后網絡請求http請求+端口調用到服務方，然后調用一個api（uri），這時候響應的時候，然后Spring框架對響應進行JSON序列化，然后寫入Socket，這時候調用方（客戶端）突然Socket端中斷連接，而Server端正在進行輸出流寫，導致如上異常問題。
然后針對當前業務場景，看了今天300個請求，有不到10個出現這種問題，超時大多3、4秒樣子，我們通知調用方增大連接池的超時時間，就不再出現這個問題。
最近氣溫變化大，冷暖轉換明顯，由於沒有及時增添衣物，注意保暖，翎野君感染風寒，現在正在調養恢復中，希望大家也多多注意，春捂秋凍。
參考文章