Project deployment to Tomcat after access to display blank page

In 51 before the holiday, the project on Tomcat or normal operation good, but yesterday the holiday to need to update the project. Usually follow the update steps, there is no problem, but yesterday updated, access to the project should jump to the login page, but it has been shown blank. Direct access to the webcontent below the error.jsp is also shown blank. If you enter a a.jsp, there will be a 404 error, which indicates that the project is correctly deployed, but access to the project is not access, always show blank. Always thought it was a problem with the new packaged war pack. However, after careful investigation with SVN found that there is nothing unusual. There is no error in the Tomcat boot log, and the project is running normally in local tomcat. The problem is too wonderful, the search on the Internet solutions are still not resolved. Finally, the network manager came over and said to restart Tomcat, because Tomcat has deployed several online projects to confirm that the reboot will not affect the business and then reboot the Tomcat. I thought restarting would still not solve the problem. But after actually restarting Tomcat, the project can be accessed normally.
Workaround: Restart Tomcat.
The cause of the problem: look at the Tomcat log is no exception, do not know how to troubleshoot. The cause of the problem is not found for the time being.

Project deployment to Tomcat after access to display blank page