tomcat啓動卡住

新部署的項目啓動tomcat後一直停在org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.16，卡在了org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/tomcat/webapps/host-manager]
將近7分鐘。

[root@app-web-2-64-0002 bin]# tail -500f ../logs/catalina.2018-07-04.out
......
04-Jul-2018 16:28:59.520 INFO [main] org.apache.catalina.startup.Catalina.load Initialization processed in 328 ms
04-Jul-2018 16:28:59.534 INFO [main] org.apache.catalina.core.StandardService.startInternal Starting service [Catalina]
04-Jul-2018 16:28:59.534 INFO [main] org.apache.catalina.core.StandardEngine.startInternal Starting Servlet Engine: Apache Tomcat/8.5.16
......
卡了近7分鐘
......
04-Jul-2018 16:35:00.238 WARNING [localhost-startStop-1] org.apache.catalina.util.SessionIdGeneratorBase.createSecureRandom Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [360,548] milliseconds.
04-Jul-2018 16:35:00.273 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/opt/tomcat/webapps/host-manager]
....

解決方法：
修改jdk的java.security文件securerandom.source項

[root@app-web-2-64-0002 bin]# grep "source=file" /usr/java/jdk1.8.0_161/jre/lib/security/java.security 
#securerandom.source=file:/dev/random
securerandom.source=file:/dev/./urandom
[root@app-web-2-64-0002 bin]#

將securerandom.source=file:/dev/random修改成securerandom.source=file:/dev/./urandom

linux或者部分unix系統提供隨機數設備是/dev/random 和/dev/urandom ，兩個有區別，urandom安全性沒有random高，但random須要時間間隔生成隨機數。jdk默認調用random。可經過 head -n 1 /devrandom 查看是否的系統會出現僞隨機數提供等待，