最近遇到linux 启动tomcat服务提示java.io.IOException: 打开的文件过多问题,如下：
21-Dec-2020 10:43:44.972 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /home/tomcat_guomi/webapps/iotAuth has finished in 7,454 ms
21-Dec-2020 10:43:44.975 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["http-nio-8090"]
21-Dec-2020 10:43:44.979 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler ["ajp-nio-8099"]
21-Dec-2020 10:43:44.984 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 7484 ms
Exception in thread "mysql-cj-abandoned-connection-cleanup" java.lang.NoClassDefFoundError: com/mysql/cj/protocol/ExportControlled
at com.mysql.cj.protocol.NetworkResources.forceClose(NetworkResources.java:53)
at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread$ConnectionFinalizerPhantomReference.finalizeResources(AbandonedConnectionCleanupThread.java:237)
at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.finalizeResource(AbandonedConnectionCleanupThread.java:215)
at com.mysql.cj.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:87)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: com.mysql.cj.protocol.ExportControlled
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1333)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1167)
... 7 more
21-Dec-2020 10:45:52.037 SEVERE [http-nio-8090-Acceptor-0] org.apache.tomcat.util.net.NioEndpoint$Acceptor.run Socket accept failed
java.io.IOException: 打开的文件过多
at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:682)
at java.lang.Thread.run(Thread.java:748)
21-Dec-2020 10:45:52.088 SEVERE [http-nio-8090-Acceptor-0] org.apache.tomcat.util.net.NioEndpoint$Acceptor.run Socket accept failed
解决办法：
查看配置
[root@localhost logs]# ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 62605 max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 62605 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited
修改配置：
[root@localhost logs]# ulimit -n 10240 [root@localhost logs]# ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 62605 max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited open files (-n) 10240 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 62605 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited [root@localhost logs]#
在此窗口下再次启动服务（注意：在此窗口下）：
就不再报错了。