写入 ObjectOutputStream 后如何读取套接字响应？答案

【问题标题】：How to read socket response after writing to ObjectOutputStream?写入 ObjectOutputStream 后如何读取套接字响应？
【发布时间】：2016-01-20 23:25:49
【问题描述】：

我正在使用Socket将任务从一台服务器发送到另一台服务器，如下所示：

private boolean sendRequest(String address, int port) {
    boolean requestComplete = false;
    try {
        Socket socket = new Socket(address, port);
        ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
        oos.writeObject("task_to_complete");

        ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
        String msg = (String)ois.readObject();
        if(msg.equals("complete")){
            requestComplete = true;
        }
        ois.close();
        oos.close();
        socket.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return requestComplete;
}

第二台服务器接收任务如下：

while (true) {

    // wait for connection
    Socket socket = serverSocket.accept();
    System.out.println("New connection accepted " + socket.getInetAddress() + ":" + socket.getPort());

    // retrieve request from server
    ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
    String msg = (String) ois.readObject();

    switch (msg) {
    case "task_to_complete":
        // do task 1
        break;
    }

    System.out.println("Task " + msg + " complete.");

    // send a message back to client with the result of the task it
    // requested
    PrintWriter out =
            new PrintWriter(socket.getOutputStream(), true);
        out.print("complete");
    ois.close();
    socket.close();
}

但我得到了错误

java.io.EOFException 在 java.io.ObjectInputStream$PeekInputStream.readFully(Unknown Source)

当我尝试从第一台服务器读取“完成”消息时： ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());.

是什么导致了这个错误？

【问题讨论】：

标签： java sockets

【解决方案1】：

你搞砸了你的协议，因为

服务器用PrintWriter.print("completed")写响应
客户端用readObject()读取它

我放了一个working demo on GitHub

【讨论】：

【解决方案2】：

尝试使用

BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

String msg = in.readLine();

if(msg.equals("complete")){
        requestComplete = true;
    }

它在类似情况下对我有用

【讨论】：

这给了我一个NullPointerException 代表“味精”。