threadedserver.java

SSD8的练习一答案

import java.io.*;  
import java.net.*;  
import java.util.*;  
 
public class ThreadedServer {  
  
  public ThreadedServer() throws Exception {  
      
    //the server socket  
    ServerSocket serSk = new ServerSocket(8000);  
      
   //the counter of clients
    int counter = 1;  
  
    while (true) {  
      Socket connectionSocket = serSk.accept();  
      System.out.println("Accepting Client " + counter + "'s Connection...\n");  
  
    // a thread for a client  
      ServerThread st = new ServerThread(connectionSocket, counter++);  
      st.start();  
    }  
  }  
  
  
  class ServerThread extends Thread {  
      
    // a client socket 
    private Socket sk;  
  
    // the counter of clients   
    private int counter;  
  
    ServerThread(Socket sk, int counter) {  
      this.sk = sk;  
      this.counter = counter;  
    }  
  
    public void run() {  
        
    // reader and writer with client and file   
      FileInputStream inFromFile = null;  
      BufferedReader inFromClient = null;  
      DataOutputStream outToClient = null;  
        
    // response the request   
      try {  
        while (true) {  
        	 inFromClient = new BufferedReader(new InputStreamReader(  
        			 sk.getInputStream()));  
                 outToClient = new DataOutputStream(sk.getOutputStream());  
         
                 System.out.println("Waiting for command...");  
                 String cmd = inFromClient.readLine();  
                 System.out.println("The request for: " + cmd);  
         
                 StringTokenizer token = new StringTokenizer(cmd);  
                 if (token.countTokens() < 2) {  
         
                   System.out.println("Command style error!");  
                   outToClient.writeBytes(" Bad Request\n\r");  
                   break;  
         
                 } 
                 else {  
         
                   String method = token.nextToken();  
                   String filename = token.nextToken(); 
                   
                   //Make sure that the filename  is correct.
                   if (filename.charAt(0) != '/') {  
                     System.out.println("Filename command error!");  
                     outToClient .writeBytes(" Bad Request\n\r");  
                     break;  
                   }  
         
               
                   filename = (filename.equals("/") ? "INDEX.HTM"  
                       : filename.substring(1));  
         
                   File file = new File(filename);  
         
                   if (!file.exists()) {  
                     System.out.println("File not existed!");  
                     outToClient.writeBytes(" Not Found\n\r");  
                     break;  
                   }  
         
                   
            //Response the right format request. Identify the file  tpye and write it to the client.  
                     
                   System.out.println("Now respond the request...");  
                   inFromFile = new FileInputStream(filename);  
         
                   byte[] by = new byte[(int) file.length()];  
                   inFromFile.read(by); 
                   
                   //response to get method
                  if( method.toLowerCase().equals("get")){
               	   if (filename.endsWith(".htm")||filename.endsWith(".html")) {  
                          outToClient.writeBytes("HTTP/1.0 200 OK" + "\n\r");  
              
                          outToClient.writeBytes("Content-Type: txt/html"  
                              + "\n\r");  
              
                          outToClient.writeBytes("Content-Length: "  
                              + file.length() + "\n\r\n\r");  
                        }  
                        else if (filename.endsWith(".jpg")||filename.endsWith(".jepg")){
                        	 outToClient.writeBytes("HTTP/1.0 200 OK" + "\n\r");  
                        	  
                             outToClient.writeBytes("Content-Type: image"  
                                 + "\n\r");  
                        }
              
                        outToClient.write(by);  
                        outToClient.flush();  
                        outToClient.writeBytes("\n\r");  
                        break;  
                      } 
                  
                  //response to put method
                  if(method.toLowerCase().equals("put")){
               	   //I ignore this method and just print the fileName
               	 System.out.println(filename);
               	   
                    break;  
                  }
                  
                  //response when the method is incorrect
                  else {
               	   System.out.println("Method error!");  
                      outToClient  
                          .writeBytes(" Bad Request\n\r");  
                      break;  
                  }
                }
                   
               }//end while  
      } catch (Exception e) {  
        e.printStackTrace();  
      } finally {  
          
         
        // Close the reader, writer and client socket.  
            System.out.println("Closing Client " + counter  
            + "\'s Connection...\n");  
  
        try {  
          if (inFromFile != null)  
            inFromFile.close();  
          if (inFromClient != null)  
            inFromClient.close();  
          if (outToClient != null)  
            outToClient.close();  
          if (sk != null)  
            sk.close();  
        } catch (IOException e) {  
        }  
      }  
    }  
  }  
  
  public static void main(String[] args) {  
      
    try {  
      ThreadedServer threadedServer = new ThreadedServer();  
  
    } catch (Exception e) {  
        
      e.printStackTrace();  
    }  
  
  }  
}