title: how to test a mysql connection is available?
body: <p>My program create 5 connections in a pool,but when the program run about 24 hours,the SQLs were executed fail,I think the connections were unavailable,I don't want to adjust the parameter in mysql,I want to modify mysql connection's strategy.When the connection is unavailable,It would close the connection and reconnect again,I didn't find the API.</p>