JMeter测试报错：java.net.SocketException: Socket closed at

报错如下：

java.net.SocketException: Socket closed at java.base/sun.nio.ch.NioSocketImpl.endRead(NioSocketImpl.java:253) at java.base/sun.nio.ch.NioSocketImpl.implRead(NioSocketImpl.java:332) at java.base/sun.nio.ch.NioSocketImpl.read(NioSocketImpl.java:355) at java.base/sun.nio.ch.NioSocketImpl$1.read(NioSocketImpl.java:808) at java.base/java.net.Socket$SocketInputStream.read(Socket.java:966) at org.apache.http.impl.io.SessionInputBufferImpl.streamRead(SessionInputBufferImpl.java:137) at org.apache.http.impl.io.SessionInputBufferImpl.fillBuffer(SessionInputBufferImpl.java:153) at org.apache.http.impl.io.SessionInputBufferImpl.readLine(SessionInputBufferImpl.java:280) at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:138) at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:56) at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259) at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163) at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:157) at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273) at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125) at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272) at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186) at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89) at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)

问题原因：

        在JMeter下，发送http 请求时，一般都是默认选择了use keepAlive（这个是什么？看后面资料），这个是连接协议，JMeter坑就在这里，默认勾选了这个（如果不勾选的话，也不会保存），但其配置JMeter.properties中的时间设置默认却是注销的，也是是说，不会等待，一旦连接空闲，则立马断开了，导致我们压测中出现了事务失败的情形。

修改方法

        修改httpclient4.idletimeout= 设置成自己觉得合理的时间，一般可设置成10-60s（表示连接空闲10s后才会断开），注意这边单位是ms。修改完成后再次压测，错误不再有了。