client-serveur (transfert de fichier du serveur vers le client)

Question

Il s'agit d'un programme de transfert de fichiers. Le client envoie un nom de fichier et si ce fichier existe, le serveur envoie le fichier au client. Je veux que le serveur envoie un message comme "le fichier n'existe pas" quand le fichier n'existe pas.

public static void main(String[] args) { 

    Socket socket = null; 
String server = "localhost"; 
    DataInputStream in; 
BufferedReader input; 
    PrintWriter output; 
int port = 1500; 

    File file; 
    file = new File("G:\\o.txt"); 
    try{ 
    if(!file.exists()) 
     file.createNewFile(); 
    } 
    catch(Exception e){ 
     System.out.println("error1"); 
    } 


try { 
    socket = new Socket(server, port); 
    System.out.println("Connected To Server With This Ip" + socket.getInetAddress() + " On This Port :" + socket.getPort()); 
} 
catch (UnknownHostException e) { 
    System.out.println(e); 

} 
catch (IOException e) { 
    System.out.println(e); 

} 


try { 
    output = new PrintWriter(socket.getOutputStream(),true); 
    input = new BufferedReader(new InputStreamReader(socket.getInputStream())); 


    String filewanted="H:\\\\o.txt"; 
    output.println(filewanted); 

    in=new DataInputStream(socket.getInputStream()); 


     int flag=0; 
     FileWriter fw = new FileWriter(file); 
     BufferedWriter bw = new BufferedWriter(fw); 
     int b=in.readInt(); 
     for(int i=1;i<=b;i++) 
      { 
       String message= input.readLine(); 
       bw.write(message); 
       bw.newLine(); 

       flag++; 
      } 
       bw.close(); 
       if(flag!=0){ 
        System.out.println("File Was Transferd Successfuly!"); 


       } 


     } 

catch (IOException e) { 
    System.out.println(e); 
} 

try { 
    socket.close(); 
} 
catch (IOException e) { 
    System.out.println(e); 
} 
} 



//server 


public static void main(String[] args) { 

ServerSocket serversocket; 
    DataOutputStream out; 
PrintWriter output; 
    BufferedReader input; 
    String linesent; 
    int lines = 0; 
    int port=1500; 

try { 

    serversocket = new ServerSocket(port); 
    System.out.println("Server Waiting For Client On Port " + serversocket.getLocalPort()+"..."); 


    while(true) { 
    Socket socket= serversocket.accept(); 
    System.out.println("Connection Accepted With This Ip: " +socket.getInetAddress() +" On This Port :" + socket.getPort()); 
    input = new BufferedReader(new InputStreamReader(socket.getInputStream())); 
      output = new PrintWriter(socket.getOutputStream(),true); 



      String f=input.readLine(); 
      File file; 
      file = new File(f); 


      BufferedReader reader = new BufferedReader(new FileReader(f)); 
      if(file.exists()) 
      { 
       while (reader.readLine() != null) 
        lines++; 
       reader.close(); 
       out=new DataOutputStream(socket.getOutputStream()); 
       out.writeInt(lines); 
       Scanner scanner=new Scanner(file); 
       while(scanner.hasNext()) 
       { 
        linesent=scanner.nextLine(); 
        output.println(linesent); 
       }   


      } 
      else { 

       throw new FileNotFoundException(f); 


      } 

    try { 
     socket.close(); 
     System.out.println("Connection closed by client."); 
    } 
    catch (IOException e) { 
     System.out.println(e); 
    } 

    } 
    } 



catch (IOException e) { 
    System.out.println(e); 
} 


} 

Answer 1

Alors pourquoi ne pas remplacer simplement:

throw new FileNotFoundException(f); 

par

output.println("file not exist");