我无法使用Java使用ssh-tunnel连接到DB。

Question

i have sql-BD with ssh-tunnel. i want connect to this BD using Java

the code i use:

    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);

Error line "Could not create connection to database server. Attempted reconnect 3 times. Giving up"

Error while executing this: " con = DriverManager.getConnection(...) "

Help me please

Answer 1

Debugging something like this is probably best done with wireshark , which will allow you to see what's actually happening on the wire, and quickly work out what's not quite right (tm) . If you're not familiar with the tool, there are plenty of tutorials around to choose from.

I think that mostly you just need to get things to match and it'll work ok:

• LocalPort is currently set to 1234 , but DriverManager.getConnection is trying to connect to 3306 .
• The script snippet is incomplete, so I assume that url is set to
  localhost/127.0.0.1 elsewhere ...
• jsch.getSession and session.setPortForwardingL both use proxyHost as a destination: I assume you have a firewall on the host (which is why you're using ssh) so trying to connect locally to the external interface address may also be blocked. Which means that session.setPortForwardingL should probably be localhost/127.0.0.1 too.