我该如何解决“写入结束"问题?和“读取结束时死".错误的ObjectInputStream和ObjectOutputStream?

问题描述

这是.

我有3个班级.

我的主:

import java.io.*;

public class ConnectionManager {
    public static void main(String argv[]) {

        try {
            PipedOutputStream pout = new PipedOutputStream();
            PipedInputStream pin = new PipedInputStream(pout);

            Sender s = new Sender(pout,true);
            Receiver r = new Receiver(pin,true);
            System.out.println("Starting threads");
            s.start();
            r.start();
        } catch (Exception e) {System.out.println(e);}
    }
}

我的发件人/制作人班:

My Sender/Producer class:

import java.io.*;

public class Sender extends Thread {
    ObjectOutputStream oos;
    boolean primitive;

    public Sender(OutputStream os, boolean primitive) {
        try {
            oos = new ObjectOutputStream(os);
            this.primitive = primitive;
        } catch (Exception e) {System.out.println(e);}
    }

    public void run() {
        try {
            System.out.println("Sending a message");
            Thread.sleep(1000);
            oos.writeInt(99);
            oos.flush();
            System.out.println("Message sent, terminating");
            oos.close();
        } catch (Exception e) {System.out.println("Sender: " + e);}
    }
}

我的接收器/消费者类:

My Receiver/Consumer class:

import java.io.*;

public class Receiver extends Thread {
    ObjectInputStream ois;
    boolean primitive;

    public Receiver(InputStream is, boolean primitive) {
        try {
            ois = new ObjectInputStream(is);
            this.primitive = primitive;
        } catch (Exception e) {System.out.println(e);}
    }

    public void run() {
        try {
            System.out.println("waiting for a message");
            int x = ois.readInt();
            System.out.println("message received: " + x);
            ois.close();
        } catch (Exception e) {System.out.println("Receiver: " + e);}

    }
}

产生此输出:

Starting threads
Sending a message
waiting for a message
Receiver: java.io.IOException: Write end dead
Sender: java.io.IOException: Read end dead

我在此页面中读到我正在获取这些例外，因为我没有关闭管道.但是即使我这样做，我仍然会得到它们.我该如何解决?

I read in this page that I'm getting these exceptions because I wasn't closing the pipes. But even if I do, I still get them. How can I fix this?

edit:之所以将流对象的类型从例如PipedInputStream转换为InputStream，然后使用InputStream构造新的ObjectInputStream是因为我希望能够发送和接收各种类型的数据，而不仅仅是int或字节.

edit: the reason I'm casting the type of the stream objects from, say, PipedInputStream to InputStream and then constructing a new ObjectInputStream using InputStream is because I want to be able to send and receive data of various types, not just int or bytes.

推荐答案

我保持纠正；并遵循EJP的建议；这是一个可行的解决方案.

I stay corrected; and following the advise by EJP; here is a working solution.

import java.io.*;
public class ConnectionManager {
    public static void main(String argv[]) throws Exception {
      PipedOutputStream pout = new PipedOutputStream();
      PipedInputStream pin = new PipedInputStream(pout);
      Sender s = new Sender(pout);
      Receiver r = new Receiver(pin);
      System.out.println("Starting threads");
      s.start();
      r.start();
    }
}

class Sender extends Thread {
  private final OutputStream os;
  Sender(OutputStream os) { this.os = os; }
  public void run() {
    try(ObjectOutputStream oos = new ObjectOutputStream(os)) {
      oos.writeInt(99);
      System.out.println("Message sent, terminating");
    } catch (Exception e) {
      System.out.println("Sender: " + e);
      e.printStackTrace();
    }
  }
}

class Receiver extends Thread {
  private final InputStream is;
  Receiver(InputStream is) {this.is = is; }
  public void run() {
    try(ObjectInputStream ois = new ObjectInputStream(is)) {
     System.out.println("waiting for a message");
     int x = ois.readInt();
     System.out.println("message received: " + x);
    } catch (Exception e) {
      System.out.println("Receiver: " + e);
      e.printStackTrace();
    }
  }
}

应打印:

Starting threads
Message sent, terminating
waiting for a message
message received: 99

注意:核心点是在 run 方法内创建 ObjectInputStreams .除此之外:删除了不必要的东西(该布尔原语；但添加了try-with-resources和打印堆栈跟踪).

Notes: the core point is to create the ObjectInputStreams within the run methods. Beyond that: removed the things not necessary (that boolean primitive; but added try-with-resources and printing stack traces).

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