Jbulider中连接oracle数据库问题？分不是问题

[tfm]

程序代码如下：
package login;
import java.sql.*;
public class conOracle {
public static void main(String args[]) {
try{
Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();
String url="jdbc:oracle:thin:@localhost:1521:orcl";
String user="teng";
String password="12345";
Connection con=DriverManager.getConnection(url,user,password);
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from help");
while (rs.next()){
System.out.println(rs.getString(0));
}
con.close();
}
catch(Exception e){
e.printStackTrace();
}
}
}
可是就是不成功！提示的问题如下：
java.sql.SQLException: Io 异常: Connection refused(DESCRIPTION=(TMP=)(VSNNUM=150999297)(ERR=12505)(ERROR_STACK=(ERROR=(CODE=12505)(EMFI=4))))

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:168)

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:210)

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:323)

at oracle.jdbc.driver.OracleConnection.<init>(OracleConnection.java:260)

at oracle.jdbc.driver.OracleDriver.getConnectionInstance(OracleDriver.java:365)

at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:260)

at java.sql.DriverManager.getConnection(DriverManager.java:512)

at java.sql.DriverManager.getConnection(DriverManager.java:172)

at login.conOracle.main(conOracle.java:30)

请问该如何解决？谢谢了