mysql集群，jdbc url寫法:
jdbc:mysql://[host:port],[host:port].../[database][?propertyName1][=propertyValue1][&propertyName2][=propertyValue2]...
oracle集群，jdbc url寫法：
jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.0.0.1)(PORT=1530))(ADDRESS=(PROTOCOL=TCP)(HOST=10.0.0.2)(PORT=1530)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=orcl)))
sid:
jdbc:oracle:thin:@10.1.1.1:1530:sid1
service_name:
jdbc:oracle:thin:@//10.1.1.1:1530/service_name