Eclipse 中连接Oracle怎么连接?java 老是有错误

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class ddd {

public static void main(String[] args) { try {
Class.forName("oracle.jdbc.driver.OracleDriver");
System.out.println("---------------------------");
String url = "jdbc:oracle:thin:@127.0.0.1:1521:ORACLE";
Connection con = DriverManager.getConnection (url,"system","system");
}
catch (ClassNotFoundException e)
{
System.out.println("---------------------------");
e.printStackTrace();
} catch (SQLException e)
{
// TODO Auto-generated catch block
System.out.println("---------------------------");
e.printStackTrace();
}
}

}

错误如下:
---------------------------
---------------------------
java.sql.SQLException: Io 异常: Connection refused(DESCRI

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class dbManage {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

try {
Class.forName("oracle.jdbc.driver.OracleDriver");
System.out.println("---------------------------");
String url = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
Connection con = DriverManager.getConnection (url,"scott","tiger");
}
catch (ClassNotFoundException e)
{
System.out.println("---------------------------");
e.printStackTrace();
} catch (SQLException e1)
{
// TODO Auto-generated catch block
System.out.println("---------------------------");
e1.printStackTrace();
}
}

}