Java：从 ObjectInputStream 读取

Question

我才刚刚开始学习Java。我的任务是创建一个文件服务器，它使用线程从多个客户端接受某些命令，例如文件获取、文件放置和文件删除。我正在使用自定义类 DataObject 来序列化和发送命令以及可能附带的任何数据。客户端是交互式的，因为它涉及用户手动输入各种命令。这意味着 ObjectInputStream readObject() 函数由于 EOFException 而无法在 while(true) 循环中工作。我该怎么做才能使服务器线程在 readObject() 处暂停，直到看到下一个对象，然后恢复 while(true) 循环？

服务器处的代码（分别为每个线程运行）：

public void run() {
    ObjectInputStream is = null;
    ObjectOutputStream os = null;
    try{
        is = new ObjectInputStream(clientSocket.getInputStream());
        os = new ObjectOutputStream(clientSocket.getOutputStream());
        while (true) {
            input = (DataObject) is.readObject();
            //System.out.println("Input has been read");
            output = CommandProcessor.process(input);
            if(output.data == null) {
                os.writeObject(output);
                if(output.message.compareToIgnoreCase("Rsp Bye")==0){
                    clientSocket.close();
                }
            }
        }
    }

客户端处的代码：

    public Talker() {
            DataObject input = new DataObject(0), output = new DataObject(0);
            try {
                log = new PrintStream("/home/meher/log.txt");
                InetAddress serverAddress = InetAddress.getByName("127.0.0.1");
                Socket serverSocket = new Socket(serverAddress, port);
                os = new ObjectOutputStream(serverSocket.getOutputStream());
                is = new ObjectInputStream(serverSocket.getInputStream());
                CommandExecuter.Hello(output);
                write(output);
                read(input);
                while(not-end-of-user-input){ //Yet to code this part
                            //Execute commands
                    }
            }

Answer 1

当流结束时，readObject 会抛出 EOFException。在您的情况下，当客户端关闭其连接时。因此，如果客户端向服务器发送一个对象并立即退出，则服务器将读取一个对象，并在下次尝试在现已关闭的连接上读取对象时获取 EOFExcpetion。

也许添加一个 QUIT 命令，其中他们都同意终止连接？

Answer 2

解决方案添加一个扫描仪来输入一些数据..在写入对象端...这将使线程保持活动状态并可用，它将等待输入.....

服务器代码

  package com.cdac.Network;

  import java.io.IOException;
  import java.io.ObjectOutputStream;
  import java.net.ServerSocket;
  import java.net.Socket;
  import java.net.SocketException;
  import java.util.Scanner;

  import com.cdac.collection.Customer;

  public class Server {


  public static void main(String[] args) throws IOException,SocketException{
    ServerSocket ss=new ServerSocket(1888);
    Customer customer=new Customer(101);
    Socket s=ss.accept();
    System.out.println("connection establishd");

    Scanner scanner=new Scanner(System.in);
    ObjectOutputStream oos=new ObjectOutputStream(s.getOutputStream());
    {
    oos.writeObject(customer);
scanner.next(); 
    }

}

 }

客户端代码

    package com.cdac.Network;

  import java.io.IOException;
  import java.io.ObjectInputStream;
   import java.net.Socket;
   import java.net.SocketException;
   import java.net.UnknownHostException;

   import com.cdac.collection.Customer;

     public class Client {

    public static void main(String[] args) throws UnknownHostException,
        IOException, SocketException, ClassNotFoundException {

    Customer customer = new Customer(101, "amit", 500);

    // String str1,str2;
    Socket s = new Socket("localhost", 1888);

    ObjectInputStream ois = new ObjectInputStream(s.getInputStream());
    {
        Object obj = ois.readObject();

        Customer c = (Customer) obj;
        System.out.println(c);
    }
}

}