hibernate+mysql too many connections异常

问题分析：

使用Hibernate连接MySQL，多次执行查询操作后会出现以下异常（执行查询的次数等于MySQL的max-connection参数的值）：

Data source rejected establishment of connection,  message from server: "Too many connections"
org.hibernate.exception.JDBCConnectionException: Cannot open connection
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:74)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
 at org.hibernate.jdbc.ConnectionManager.openConnectionCaused by: com.mysql.jdbc.exceptions.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
 at com.mysql.jdbc.SQLError.createSQLException

 解决方法:

在执行完查询操作后，仅仅调用了session.close();来关闭session，而没有

调用factory.close();来关闭SessionFanctory。

二者都关闭后不再出现上述异常。