Question

I have number of sockets connected to different systems with different ip-address with different port numbers. my question is I have to run one program in any system to communicate all the sockets at a time and how can i get the messages from sockets in parallel?

While I am using single socket it will work fine and I am getting messages continuously from hyper terminal. more than one connected ,then I am getting response from first one only.. so please provide the solution asap

---

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.Socket;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.HashMap;
import com.ibatis.sqlmap.client.SqlMapClient;

public class Client1 extends Thread {
    static Socket socket;
    static Socket socket1;
    static String DATE_FORMAT_NOW = "yyyy-MM-dd HH:mm:ss";
    static SqlMapClient sqlMap=GetDBConnection.sqlMap;
    static BufferedReader br = null;
    static DataOutputStream dos=null;
    static BufferedReader br1 = null;
    static DataOutputStream dos1=null;
    public static void main(String args[]){
        try{
            String host="192.168.1.151";
            int port=5002;
            String host1="192.168.1.150";
            int port1=5001;
            socket = new Socket(host, port);
            socket1=new Socket(host1, port1);
            dos = new DataOutputStream(socket.getOutputStream());
            br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            dos1 = new DataOutputStream(socket1.getOutputStream());
            br1 = new BufferedReader(new InputStreamReader(socket1.getInputStream()));

            Thread t = new Thread(new Runnable() {
            public void run() {
                while(socket.isConnected()) {
                    try{
                        HashMap map = new HashMap();
                        String str = br.readLine();
                        Calendar cal = Calendar.getInstance();
                        SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
                        String time = sdf.format(cal.getTime());
                        map.put("data", str);
                        map.put("port", socket.getPort());
                        map.put("date_time", time);
                        sqlMap.insert("insert", map);
                    }
                    catch(Exception e){
                        e.printStackTrace();
                    }
                }
               }
            });

            Thread t1 = new Thread(new Runnable() {
            public void run() {
                while(socket1.isConnected()) {
                    try{
                        HashMap map = new HashMap();
                        String str = br1.readLine();
                        Calendar cal = Calendar.getInstance();
                        SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
                        String time = sdf.format(cal.getTime());
                        map.put("data", str);
                        map.put("port", socket1.getPort());
                        map.put("date_time", time);
                        sqlMap.insert("insert", map);
                    }
                    catch(Exception e){
                        e.printStackTrace();
                    }
                  }
                }
            });

            t.start();
            t1.start();
            }
            catch(Exception e){
                e.printStackTrace();
            }
    }
}

I am running two threads for two sockets its work fine, but if I have 100 sockets then how can I do it? I can’t create 100’s of threads…so provide the best solution..

---

public class Client implements Runnable{

    public static final String DATE_FORMAT_NOW = "yyyy-MM-dd HH:mm:ss";
        static BufferedReader br = null;
        static DataOutputStream dos=null;
        static Socket socket = null;
        SqlMapClient sqlMap=GetDBConnection.sqlMap;

        Client(String host, int port)
        {
            try {

                socket = new Socket(host, port);
            } catch (UnknownHostException e) {
                        e.printStackTrace();
            } catch (IOException e) {
                        e.printStackTrace();
            } 
        }

    public void run()
    {
        try {

            HashMap map = new HashMap(5); 
            String str;
            int prt=socket.getPort();
            dos = new DataOutputStream(socket.getOutputStream());
            br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            while((str=br.readLine())!=null)
            {
                Calendar cal = Calendar.getInstance();
                SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT_NOW);
                String time = sdf.format(cal.getTime());
                map.put("data", str);

                map.put("port",prt );
                map.put("date_time", time);
                sqlMap.insert("insert", map);
             }
        }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            finally 
            {
                try {

                    socket.close();
                    dos.close();
                    br.close();
                } catch (IOException e) {
                        e.printStackTrace();
                }
            }
    }

    public static void main(String args[]) 
    {
        ResultSet rs=null; 
        Connection con = null;

      try {
            Class.forName("org.postgresql.Driver");
            con = DriverManager.getConnection("jdbc:postgresql://localhost:5432/Socket","username","passwd");
            Statement st=con.createStatement(); 
            String vsql="select port, ip_addr from port_instrument";
            rs=st.executeQuery(vsql);
               while (rs.next()) {
                 String id = rs.getString(1);

                 String ipaddr = rs.getString(2);

                 new Thread(new Client(ipaddr, Integer.parseInt(id))).start();

               }
       }
       catch(Exception e)
       {
         e.printStackTrace();
       }
       finally{
           try {
                con.close();
                rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
       }
    }
}

By using this code we can communicate with the single socket only. In my database I have 5 sockets but finally I get communication from last socket(5) only.

Answer 1

You might want to write a communication class that implements Runnable and does all the socket comms. You could then create an instance of this class for each socket and run the classes in some sort of thread pool.

Edit: Here’s a start for you

public class SocketHandler implements Runnable
{
  private Socket socket;

  public SocketHandler(String host, int port)
  {
    socket = new Socket(host, port);
  }

  public void run()
  {
    //Do the comms to the remote server
  }
}