sqlforwarder.java

Java写的TDS协议(JDBC/ODBC)实现

package net.sourceforge.jtds.tools;

import java.net.Socket;
import java.net.ServerSocket;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class SqlForwarder
{
    String host = "localhost";
    String logfile = null;
    int port = 1433;
    int listenPort = 1444;
        int lognum = 0;

    byte[] readPacket(InputStream input) throws IOException
    {
        byte[] hdr = new byte[8];
        int len = input.read(hdr);
        if (len < 8)
        {
            return null;
        }
        int packetlen = ((((int)hdr[2]) & 0xff) << 8) + (((int)hdr[3]) & 0xff);
        byte[] data = new byte[packetlen];
        while (len < packetlen)
        {
            len += input.read(data, len, packetlen - len);
        }
        for (int i = 0; i < 8; i++)
        {
            data[i] = hdr[i];
        }
        return data;
    }

    class ConnectionThread extends Thread
    {
        Socket client;
        Socket server;

        ConnectionThread(Socket client, Socket server)
        {
            this.client = client;
            this.server = server;
        }

        public void run()
        {
            try
            {
                InputStream input[] = new InputStream[2];
                input[0] = client.getInputStream();
                input[1] = server.getInputStream();

                OutputStream output[] = new OutputStream[2];
                output[0] = server.getOutputStream();
                output[1] = client.getOutputStream();

                PacketLogger log = null;
                if (logfile == null)
                {
                    log = new PacketLogger("filter" + lognum++ + ".log");
                }
                                else
                                  log =  new PacketLogger(logfile + lognum++ + ".log");

                int direction = 0;
                while (true)
                {
                    byte [] data = readPacket(input[direction]);
                    if (data == null)
                    {
                        break;
                    }
                    output[direction].write(data);
                    if (log != null)
                    {
                        log.log(data);
                    }
                    if (data[1] != 0)
                    {
                        direction = 1 - direction;
                    }
                }
                client.close();
                server.close();
            }
            catch (IOException unused)
            {
            }
        }
    }

    SqlForwarder()
    {
    }

    void run() throws IOException
    {
        System.out.println("Listening on port " + listenPort + "; Connecting to " + host + " at port " + port);
        ServerSocket srv = new ServerSocket(listenPort);
        while (true)
        {
            Socket client = srv.accept();
            Socket server = new Socket(host, port);
            ConnectionThread t = new ConnectionThread(client, server);
            t.start();
        }
    }

    void parseArgs(String args[]) throws NumberFormatException
    {
        for (int i = 0; i < args.length; i++)
        {
            String arg = args[i];
            if (arg.equals("-server"))
            {
                i++;
                host = args[i];
            }
            else if (arg.equals("-port"))
            {
                i++;
                port = Integer.parseInt(args[i]);
            }
            else if (arg.equals("-listen"))
            {
                i++;
                listenPort = Integer.parseInt(args[i]);
            }
            else if (arg.equals("-log"))
            {
                i++;
                logfile = args[i];
            }
        }
    }

    public static void main(String args[])
        throws IOException
    {
        SqlForwarder app = new SqlForwarder();
        app.parseArgs(args);
        app.run();
    }
}