tomcat启动太慢，耗时很长的问题 Creation of SecureRandom instance for ...

tomcat启动很长时间，tomcat输出日志：

INFO [localhost-startStop-1] org.apache.catalina.util.SessionIdGeneratorBase.createSecureRandom Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [142,478] milliseconds.

最终解决问题的办法，修改java参数，得到解决：

vim $JAVA_HOME/jre/lib/security/java.security 

修改内容：

#securerandom.source=file:/dev/random     #修改前

securerandom.source=file:/dev/./urandom   #修改后，注意"u"