问到mysql的java SSH连接，但出现错误:无法绑定本地端口

EN

   com.jcraft.jsch.JSchException: PortForwardingL: local port 127.0.0.1:3306 cannot be bound.
    at com.jcraft.jsch.PortWatcher.<init>(PortWatcher.java:158)
    at com.jcraft.jsch.PortWatcher.addPort(PortWatcher.java:110)
    at com.jcraft.jsch.Session.setPortForwardingL(Session.java:1847)
    at com.jcraft.jsch.Session.setPortForwardingL(Session.java:1828)
    at com.jcraft.jsch.Session.setPortForwardingL(Session.java:1809)
    at com.jcraft.jsch.Session.setPortForwardingL(Session.java:1792)
    at connectsshserver.CTestDriver.doSshTunnel(CTestDriver.java:29)
    at connectsshserver.CTestDriver.main(CTestDriver.java:47)
Caused by: java.net.BindException: Address already in use: JVM_Bind
    at java.net.DualStackPlainSocketImpl.bind0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketBind(DualStackPlainSocketImpl.java:106)
    at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387)
    at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:190)
    at java.net.ServerSocket.bind(ServerSocket.java:375)
    at java.net.ServerSocket.<init>(ServerSocket.java:237)
    at com.jcraft.jsch.PortWatcher.<init>(PortWatcher.java:150)

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;

import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session; 

public class CTestDriver {
    private static void doSshTunnel(String strSshUser, String strSshPassword, String strSshHost, int nSshPort,
            String strRemoteHost, int nLocalPort, int nRemotePort) throws JSchException {
        final JSch jsch = new JSch();
        Session session = jsch.getSession(strSshUser, strSshHost, 21098);
        session.setPassword(strSshPassword);

        final Properties config = new Properties();
        config.put("StrictHostKeyChecking", "no");
        session.setConfig(config);
        session.connect(30000);
     // String boundaddress ="0.0.0.0";
//t assinged_port=session.setPortForwardingL(boundaddress,lport, rhost, rport);
        session.setPortForwardingL(
                nLocalPort, strRemoteHost, nRemotePort);
    }

    public static void main(String[] args) {
        try {

            String strSshUser = "softeuab"; // SSH loging username
             String strSshPassword = "SP1234a1234b"; // SSH login password
            String strSshHost = "host47.registrar-servers.com";//me or ip or                                            // SSH server
            int nSshPort = 21098; // remote SSH host port number
            String strRemoteHost = "host47.registrar-servers.com"; // hostname or
                                                             // ip of
                         // your     // database server
            int nLocalPort =3306;//cal port number use to bind SSH tunnel
            int nRemotePort = 3306; // remote port number of your database
            String strDbUser = "softeuab_mohamed"; // database loging username
            String strDbPassword = "1234a1234b"; // database login password
            CTestDriver.doSshTunnel(strSshUser, strSshPassword, strSshHost, nSshPort, strRemoteHost, nLocalPort,
                     nRemotePort);
            Class.forName("com.mysql.jdbc.Driver");
             Connection con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:" + nLocalPort, strDbUser,
               strDbPassword);

            con.close();
   //   Connection      con=Connect.ConnectDB();
    //  con.close();


        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            System.exit(0);
        }
    }
}

session.setPortForwardingL(
                nLocalPort, strRemoteHost, nRemotePort);