Tomcat启动时Creation of SecureRandom instance for session ID很慢

启动tomcat很慢，检查后发现：
[localhost-startStop-1]
org.apache.catalina.util.SessionIdGeneratorBase.createSecureRandom Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [131,830] milliseconds。

主要时间都花在Creation of SecureRandom instance上了
。

解决办法：

先检查$JAVA_HOME/jre/lib/security/java.security中用的file:/dev/./random！是否前面少了个u！！如果是，改成file:/dev/urandom后，重启tomcat，sucess。