属性说明
    druid.mysql.usePingMethod配置MySqlValidConnectionChecker是否用com.mysql.jdbc.Connection.ping()方法检测连接是否有效
    druid.oracle.fatalErrorCodes
    druid.oracle.pingTimeout
    druid.testWhileIdle
    druid.testOnBorrow
    druid.validationQuery
    druid.filters
    druid.timeBetweenLogStatsMillis
    druid.stat.sql.MaxSize
    druid.useGloalDataSourceStat