http://www.eygle.com/digest/2008/06/jdbcoracle_rac.html（转）
jdbc连接oracle的连接串如下：
     String url="jdbc:oracle:thin:@(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = host2)(PORT = 1521))(ADDRESS = (PROTOCOL = TCP)(HOST = host1)(PORT = 1521))(LOAD_BALANCE = yes)(FAILOVER = ON)(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = db.domain)(FAILOVER_MODE=(TYPE = SELECT)(METHOD = BASIC)(RETIRES = 20)(DELAY = 15))))";

java测试程序如下：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Test {

public static void main(String arg[]) {
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
String url="jdbc:oracle:thin:@(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = host1)(PORT = 1521))(ADDRESS = (PROTOCOL = TCP)(HOST = host2)(PORT = 1521))(LOAD_BALANCE = yes)(FAILOVER = ON)(CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = db.domain)(FAILOVER_MODE=(TYPE = SELECT)(METHOD = BASIC)(RETIRES = 20)(DELAY = 15))))";
Connection c = DriverManager.getConnection(url,"aa","aa");
Statement s = c.createStatement();
ResultSet r = s.executeQuery("select 1 from dual");
while(r.next()) {
System.out.println(r.getString(1));
}
}catch(Exception e) {
System.out.println(e.toString());
}
}

}