nets.java

Java程序设计技巧与开发实例附书源代码。

import java.net.*;
import java.io.*;
import java.awt.*;

public class Nets
{
   static Socket mySocket; //define an socket for client connections
   static ServerSocket SS;
   // define as the server socket
   static DataInputStream datain; //define an input stream
   static DataOutputStream dataout;
   static int MumServers;

   public static void main(String args[]) throws IOException
   {
      System.out.println("Server coming up ...");

      try
      {
         SS = new ServerSocket(1237);
      }
      catch (IOException eos)
      {
         System.out.println("Error opening server socket.");
         System.exit(1);
      }

      while (true)
      { //wait for connetion infinitely
         try
         {
            mySocket = SS.accept(); // Accept client connection
         }
         catch (IOException e)
         {
            System.out.println(" I/O error waiting. Exiting.");
            System.exit(1);
         }

         //setup the input and the output stream
         datain = new DataInputStream(
             new BufferedInputStream(mySocket.getInputStream()));
         dataout = new DataOutputStream(
             new BufferedOutputStream(mySocket.getOutputStream()));
         ServerBody(); //code for actual computation
      }
   }

   public static void ServerBody() throws IOException
   {

      int i, j, k, sum;
      int TotNum = 0, NumRows = 0; //Values for N, R
      int A[][], B[][], Result[][];

      try
      {
         TotNum = datain.read(); // read the value of N
      }
      catch (IOException e)
      {
         System.out.println(
             "I/O error getting information  from client.Exiting");
         System.exit(1);
      }

      try
      {
         NumRows = datain.read(); //read value of R
      }
      catch (IOException e)
      {
         System.out.println(
             "I/O error while getting info from client. Exiting.");
         System.exit(1);
      }

      // Now N, T are Known, we can actually instantiate the matrices
      A = new int[NumRows][TotNum];
      B = new int[TotNum][TotNum];
      Result = new int[NumRows][TotNum];

      System.out.println("Receiving Matrix A from client.");
      //Read the value for Matrix A
      for (i = 0; i < NumRows; i++)
      {
         for (j = 0; j < TotNum; j++)
         {
            try
            {
               A[i][j] = datain.readInt();
            }
            catch (IOException e)
            {
               System.out.println(
                   "I/O error while getting info from client. Exiting");
               System.exit(1);
            }
         }
      }
      System.out.println("receiving matrix B from client.");
      //read the value for Matrix B

      for (i = 0; i < TotNum; i++)
      {
         for (j = 0; j < TotNum; j++)
         {
            try
            {
               B[i][j] = datain.readInt();
            }
            catch (IOException e)
            {
               System.out.println(
                   " I/O Error while getting info from client. Exiting");
               System.exit(1);
            }
         }
      }

      //Compute the matrix multiplication
      for (i = 0; i < NumRows; i++)
      {
         for (j = 0; j < TotNum; j++)
         {
            sum = 0;
            for (k = 0; k < TotNum; k++)
            {
               sum += A[i][k] * B[k][j];
            }
            Result[i][j] = sum;
         }
      }

      for (i = 0; i < NumRows; i++)
      {
         for (j = 0; j < TotNum; j++)
         {
            try
            {
               dataout.writeInt(Result[i][j]);
            }
            catch (IOException e)
            {
               System.out.println("I/O error while writing to client. Exiting");
               System.exit(1);
            }
         }
      }
      dataout.flush();
      System.out.println("Resultant Matrix sent to client");
   }
}