Jmeter返回org.apache.http.NoHttpResponseException: The target server failed to respond解决办法
1、问题：这段时间使用jmeter压测时（300个请求，持续压300s，加速期10s），压力平稳时偶然错误，部分请求失败事务报错信息如下
org.apache.http.NoHttpResponseException: The target server failed to respond
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:95)
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:61)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254)
at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289)
at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252)
at org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191)
at org.apache.jmeter.protocol.http.sampler.MeasuringConnectionManager$MeasuredConnection.receiveResponseHeader(MeasuringConnectionManager.java:201)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127)
at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:517)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:331)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:74)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1146)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1135)
at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:434)
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:261)
at java.lang.Thread.run(Unknown Source)
2、原因：在JMeter下，发送http 请求时，默认选择了use keepAlive（Keep-Alive通俗地讲，就是所谓的持久连接，对于http这种大量的短连接的服务来说，开启持久连接的好处可节省大量的TCP连接过程的开销，据apache的官方文档称对包含大量图片的HTML文档造成的延时起到50%的加速作用），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，不会等待，一旦连接空闲，则立即断开了，导致压测中出现了事务失败的情形。
可访问https://wiki.apache.org/jmeter/JMeterSocketClosed查看官网解释
3、解决方法：
找到jmeter安装路径D:\apache-jmeter-3.2\bin下的jmeter.properties，编辑，设置httpclient4.idletimeout=<time in ms>，注意单位是ms，设置成觉得合理的时间，一般可设置成10-60s（表示连接空闲10s后才会断开）。修改完成后再次压测，错误就没出现。
例：httpclient4.idletimeout=3000，意思是连接空闲3s才会断开
4、KeepAlive
日常在浏览器查看请求头也可看到KeepAlive，本章重点不在这里，有兴趣可参考
http://blog.csdn.net/gaoshanliushui2009/article/details/8020240
http://liuzhigong.blog.163.com/blog/static/1782723752011412551547/
