java - 套接字客户端-服务器在发送到服务器端后卡住

Question

我需要为我的项目制作一个带有套接字的文件传输应用程序。到目前为止，我已经编写了一个简单的客户端-服务器通信，但是每当我尝试从客户端输出接收字符数据到服务器输入时，我的代码就会锁定。代码如下:

服务器

public class ClientServer extends Thread {

Socket connection;
File file;

public ClientServer (Socket connection){
    this.connection = connection;
    this.start();
}

public void run(){
    try {
        System.out.println("Starting Client Thread...");
        BufferedReader input = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        DataOutputStream output = new DataOutputStream(connection.getOutputStream());
        System.out.println("IO created...");
        System.out.println("input = " + input.readLine());

        String s = input.readLine();

        System.out.println(s);
        file = new File(s);

        if(file.isFile()){
            System.out.println("File " + s + " exists");

            FileInputStream fileOutput = new FileInputStream(file);
            byte[] buffer = new byte[1024*1024];
            int length = 0;
                while((length = fileOutput.read(buffer)) != -1){
                    output.write(buffer, 0, buffer.length);
                }
            System.out.println("File " + s + " sent.");
            fileOutput.close();
            output.close();
            input.close();
        } else {
            System.out.println(s + " is not a file");
        }

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    finally{
        try {
            connection.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }               
}


public static void main(String[] args) throws IOException {

    int serverPort = 9000;

    ServerSocket server = new ServerSocket(serverPort);

        Socket connectionSocket = server.accept();

        ClientServer con = new ClientServer(connectionSocket);
}
}

客户端

public static void main(String[] args) throws IOException {
    // TODO Auto-generated method stub

    String ip = "localhost";
    int port = 9000;
    Socket clientSocket = new Socket(ip, port);


    BufferedWriter out = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));

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

    BufferedReader userInput = new BufferedReader(new InputStreamReader(System.in));

    System.out.println("Enter valid file name and press 'ENTER': ");

    String message = userInput.readLine();
    System.out.println("Sending message...");
    out.write(message);
    System.out.println("File name sent: " + message);

    int length = in.readInt();
    byte[] buffer = new byte[length];
    for(int i=0; i< length; i++){

        buffer[i] = in.readByte();
        System.out.println("Reading byte... " + buffer[i]);
    }
    File file = new File("C:/Users/Dominik/Desktop/lol/new.php");
    FileOutputStream fos = new FileOutputStream(file);
    fos.write(buffer);
    fos.close();

    clientSocket.close();
    System.out.println("Closing");
}
}

编辑

这是我的输出，因为没有一个答案可以解决我的问题(可能是我做错了什么):

客户端

输入有效的文件名并按“ENTER”:
C:\\Users\\Dominik\\Desktop\\Login.php//我的输入
正在发送消息...
发送的文件名:C:\\Users\\Dominik\\Desktop\\Login.php

服务器

正在启动客户端线程...
IO 创建...
//服务器应该sysout发送的消息，但它没有这样做，它只是卡在这里

Answer 1

您尝试在客户端中readInt，但在服务器端您仅发送文件内容。我看起来您在发送文件之前忘记发送文件大小。