我有带ssh隧道的sqlbd。我想用java连接到这个bd
我使用的代码：

Connection con = null;
    JSch jsch = new JSch();

    int localPort = 1234;

    Session session = jsch.getSession(proxyUser, proxyHost, 22);
    java.util.Properties config = new java.util.Properties();
    config.put("StrictHostKeyChecking", "no");
    session.setConfig(config);
    session.setPassword(proxyPassword);

    session.setConfig("PreferredAuthentications", "publickey,keyboard-interactive,password");
    session.connect();
    session.setPortForwardingL(localPort, proxyHost, 3306);

    Properties properties = new Properties();
    properties.setProperty("user", user);
    properties.setProperty("password", password);
    properties.setProperty("useUnicode", "true");
    properties.setProperty("characterEncoding", "UTF-8");
    Class.forName("com.mysql.jdbc.Driver").newInstance();
    con = DriverManager.getConnection(
            "jdbc:mysql://" + url + ":3306/" + nameBD + "?autoReconnect=true", properties);

错误行“无法创建到数据库服务器的连接。尝试重新连接3次。“放弃”
执行此操作时出错：“con=drivermanager.getconnection（…）”
请帮帮我