yingqin678/experience

解决问题的经验

experience's Issues

GSON问题

int转double：https://www.jianshu.com/p/eafce9689e7d

zk问题

启动报错：zookeeper.KeeperException$UnimplementedException: KeeperErrorCode = Unimplemented for
原因：zk客户端与服务器版本不一致：https://www.jianshu.com/p/384442962e86

linux相关的命令

强制卸载nfs：nfsstat -m
umount -f/l

mvn打包

maven编码gbk的不可映射字符：https://www.cnblogs.com/xdp-gacl/p/4239006.html

mybatis问题

mybatis useGeneratedKeys无法返回主键解决：https://blog.csdn.net/qq_29992111/article/details/80530195

记载一次HTTP返回码406的解决过程

系统架构：NGINX+Tomcat，NGINX为HTTPS服务，Tomcat至NGINX为HTTP
客户端:对接两种客户端
服务器:使用spring mvc框架

问题描述：服务器提供一个下载图片接口，通过将文件流写入响应stream中，并设置header中contentType字段提供客户端下载图片(图片为敏感信息，不能通过静态URL下载)，一种客户端可以正常通过接口下载，另一种客户端请求返回406(406解释：https://segmentfault.com/q/1010000006745584)
解决思路：

从406描述中可以推测，大概率是请求头中accept的问题，那么咱们就把两种客户端的accept都抓出来对比一下，看下是具体是哪个(此时尚不清楚是哪个环节返回的406)，然后再根据请求环节一步步找出返回406的点，并设法解决。

解决步骤：

1.NGINX对外是HTTPS服务，抓取得请求是密文，无法查看，只能抓Tomcat日志，看是否请求到了后端被拒绝的，使用tcpdump抓包，抓取两种客户端请求，发现请求正常的客户端，accept包含*/,为接受所有响应类型，因此没有此类问题；406的请求accept为image/wpn;image/；问题就在某个环节的响应类型不在accept之中。
2.为方便定位，使用本地Tomcat进行调测，发现相同406请求头，本地是正常返回的，那么问题来了，本地和环境上的区别只是存在部分开源jar包进行过升级，看来罪魁祸首快要找到了。
3经过排查，发现问题就是spring框架的包升级导致的。从springframe的listener进入进行调试，很快定位到问题的原因。
4.原因：4.3.16版本未对producers于accept进行校验，5.X(具体版本号不记得了)校验了producers是否在accept中存在。我们requestMapping时，未配置producers，默认值是text/html，不在image/*中，返回406错误,
5.解决：找到问题原因，在对应方法上增加标注：producers:image/jpg，即解决问题

tomcat connectionTimeout 问题

https://blog.csdn.net/coder_xia/article/details/77183615

servlet

设置gzip压缩：http://kuchaguangjie.iteye.com/blog/763304

kafka客户端发送消息导致Tomcat僵死

http://www.it1352.com/542429.html
出现大量日志

"http-bio-8080-exec-168" #257 daemon prio=5 os_prio=0 tid=0x00007f52ec5cc800 nid=0x501 waiting on condition [0x00007f52dcc03000]
java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x000000070b8cb2a8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
at org.apache.kafka.clients.producer.internals.BufferPool.allocate(BufferPool.java:137)
at org.apache.kafka.clients.producer.internals.RecordAccumulator.append(RecordAccumulator.java:157)
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:338)
at com.huawei.opengw.mq.remoting.kafka.version082.KafkaProducer082.send(KafkaProducer082.java:122)
at com.huawei.opengw.mq.rpc.MQInvoker.doInvoke(MQInvoker.java:216)
at com.alibaba.dubbo.rpc.protocol.AbstractInvoker.invoke(AbstractInvoker.java:142)
at com.alibaba.dubbo.rpc.listener.ListenerInvokerWrapper.invoke(ListenerInvokerWrapper.java:73)
at com.alibaba.dubbo.rpc.filter.GenericImplFilter.invoke(GenericImplFilter.java:172)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:68)
at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:74)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:68)
at com.alibaba.dubbo.rpc.protocol.dubbo.filter.FutureFilter.invoke(FutureFilter.java:53)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:68)
at com.alibaba.dubbo.rpc.filter.ConsumerContextFilter.invoke(ConsumerContextFilter.java:47)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:68)
at com.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:52)
at com.huawei.opengw.dubboex.rpc.cluster.opengw.support.MFailoverClusterInvoker.doInvoke(MFailoverClusterInvoker.java:115)
at com.huawei.opengw.dubboex.rpc.cluster.opengw.support.AbstractMClusterInvoker.invoke(AbstractMClusterInvoker.java:344)
at com.alibaba.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker.invoke(MockClusterInvoker.java:70)
at com.alibaba.dubbo.rpc.proxy.InvokerInvocationHandler.invoke(InvokerInvocationHandler.java:51)
at com.sun.proxy.$Proxy46.$invoke(Unknown Source)
at com.huawei.opengw.mq.api.MQClient.sendMessage(MQClient.java:567)
at com.huawei.skytone.dmq.DmqClient.sendMessage(DmqClient.java:377)
at com.huawei.skytone.dmq.DmqClient.sendMessage(DmqClient.java:349)
at com.huawei.vsim.common.dmq.push.PushMsgService.postApkLogOnMSG(PushMsgService.java:90)
at com.huawei.vsim.rest.v1.ifs.ReportLog.sendDMQ(ReportLog.java:278)
at com.huawei.vsim.rest.v1.ifs.ReportLog.service(ReportLog.java:180)
at com.huawei.vsim.rest.v1.ifs.ReportLog.service(ReportLog.java:45)
at com.huawei.vsim.rest.v1.ClientServlet.execute(ClientServlet.java:437)
at com.huawei.vsim.rest.v1.ClientServlet.doRequest(ClientServlet.java:354)
at com.huawei.vsim.rest.v1.ClientServlet.doPost(ClientServlet.java:185)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.filters.CorsFilter.handleNonCORS(CorsFilter.java:458)
at org.apache.catalina.filters.CorsFilter.doFilter(CorsFilter.java:177)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.huawei.vsim.common.container.EncodingFilter.doFilter(EncodingFilter.java:63)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
- locked <0x000000070b8cc340> (a org.apache.tomcat.util.net.SocketWrapper)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)