java.net.BindException: Address already in use: connect
at java.base/java.net.PlainSocketImpl.connect0(Native Method)
at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:101)
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
at java.base/java.net.Socket.connect(Socket.java:591)
at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:75)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl$JMeterDefaultHttpClientConnectionOperator.connect(HTTPHC4Impl.java:336)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:374)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:393)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:843)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:574)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:67)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1231)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1220)
at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:622)
at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:546)
at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:486)
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:253)
at java.base/java.lang.Thread.run(Thread.java:835)
如果报如上错误，可能是因为发送请求时，端口被占用（应该是端口不够用了）
问题原因：操作系统会为TCP/IP服务预留临时端口，Jmeter在跑并发测试的时候每开启一个线程（new socket操作）就会占用一个临时端口，若TCP/IP端口被占完了，而且没有及时释放（socket.close()操作不能立即释放绑定的端口，而是把端口设置为TIME_WAIT状态，过段时间才会真正释放，默认是240s），就会出现Java.net.BindException: Address already in use: connect这种情况。
解决办法：
加快被占用端口的释放速度
原文链接：
https://blog.csdn.net/liuzhenwen/article/details/89354901
上面的方法对于阿里云服务器来说，相关文件配置位置可能不一样，使用阿里云官方说明：
通过以下两种方式，修改内核参数。
注：调整内核参数后，内核处于不稳定状态，请务必重启实例。
执行如下命令，临时修改内核参数。
/sbin/sysctl -w kernel.parameter="[$Example]"
注：[$Example]为参数值，如sysctl -w net.ipv4.tcp_tw_recycle="0"命令，将参数值改为0。
通过修改配置文件的方式修改内核参数。
执行如下命令，修改/etc/sysctl.conf文件中的参数。
vi /etc/sysctl.conf
执行如下命令，使配置生效。
/sbin/sysctl -p
https://help.aliyun.com/knowledge_detail/41334.html
