502 Proxy Error The proxy server received an invalid response from an upstream server Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /wpsp/.
Reason: Error reading from remote server
Apache/2.2.15 (CentOS) Server at www.xaut.edu.cn Port 80
解决方法：
重启Apache，再重启Tomcat即可。