问题是在调用HQL时，有时会得到正确的响应或返回此日志错误：
DEBUG SqlExceptionHelper - could not extract ResultSet [n/a]
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 902,724 milliseconds ago. The last packet sent successfully to the server was 23,553 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45).
Caused by: java.net.SocketException: Connection reset by peer: socket write error at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:109)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3964)
... 96 more
WARN SqlExceptionHelper - SQL Error: 0, SQLState: 08S01
ERROR SqlExceptionHelper - Communications link failure