我们都知道，ORACLE 对外提供服务有 这么几种方式 THIN CONNECT ,OCI CONNECT ,DATALINK等数据连接方式。

    1.THIN Connect

    在单实例情况下,JDBC Connect String ： jdbc:oracle:thin:10.11.1.243:1521/orcl

   其中IP 10.11.1.243:1521 服务器IP地址和Lisener监听端口。

    orcl 为数据服务名。

    在RAC环境中，JDBC Connect String ：  

jdbc:oracle:thin:@(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)

　　　　　　(HOST = 10.11.1.231)(PORT = 1521))(ADDRESS = (PROTOCOL = TCP)

　　　　　　(HOST = 10.11.1.232)(PORT = 1521))(LOAD_BALANCE = yes)(FAILOVER = ON)(CONNECT_DATA =http://www.mamicode.com/(SERVER = DEDICATED)(SERVICE_NAME = racdb.its)(FAILOVER_MODE=(TYPE = SELECT)(METHOD = BASIC)(RETIRES = 20)(DELAY = 15))))

      其中HOST为两个几点的Lisener的配置。FAILOVER关键字 为配置故障切换。Load_balance为负载均衡打开设置。

     SERVICE_NAME 为RAC系统的数据库实例名。

   以下为JAVA系统的代码:

java demo

   2.OCI 连接的配置 也就是通常的TNS 配置

      单实例的情况：很简单 不多做累赘

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 10.11.1.243)(PORT = 1521))
    (CONNECT_DATA =http://www.mamicode.com/
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

      RAC情况:

RACDB1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb1-vip.its)(PORT = 1521))
    (CONNECT_DATA =http://www.mamicode.com/
      (SERVER = DEDICATED)
      (SERVICE_NAME = racdb)
      (INSTANCE_NAME = racdb1)
    )
  )

RACDB =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb1-vip.its)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb2-vip.its)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (CONNECT_DATA =http://www.mamicode.com/
      (SERVER = DEDICATED)
      (SERVICE_NAME = racdb)
    )
  )

LISTENERS_RACDB =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb1-vip.its)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb2-vip.its)(PORT = 1521))
  )

EXTPROC_CONNECTION_DATA =http://www.mamicode.com/
  (DESCRIPTION =
    (ADDRESS_LIST =

RACDB =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb1-vip.its)(PORT = 1521))
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb2-vip.its)(PORT = 1521))
    (LOAD_BALANCE = yes)
    (CONNECT_DATA =http://www.mamicode.com/
      (SERVER = DEDICATED)
      (SERVICE_NAME = racdb)
    )
  )

LISTENERS_RACDB =
  (ADDRESS_LIST =
    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb1-vip.its)(PORT = 1521))    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb2-vip.its)(PORT = 1521))
  )
EXTPROC_CONNECTION_DATA =http://www.mamicode.com/
  (DESCRIPTION =    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
    )
    (CONNECT_DATA =http://www.mamicode.com/
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
  )
RACDB2 =  (DESCRIPTION =    (ADDRESS = (PROTOCOL = TCP)(HOST = racdb2-vip.its)(PORT = 1521))    (CONNECT_DATA =http://www.mamicode.com/
      (SERVER = DEDICATED)
      (SERVICE_NAME = racdb)
      (INSTANCE_NAME = racdb2)
    )
  )

转：http://www.cnblogs.com/jerryxing/archive/2012/10/17/2728061.html

RAC JDBC 配置