通过 Java 套接字发送对象

Question

我有一个班级名称播放器

public JLabel imagen;

public String Nombre;

public Player(int x, int y, int width, int height, Icon icono, String name){
    imagen = Player(x, y, width, height, icono);
    Nombre = name;
}
public JLabel Player(int x, int y, int width, int height, Icon icono){
    JLabel imagen = new JLabel(icono);
    imagen.setLocation(x, y);
    imagen.setSize(width, height);
    return imagen;
}

（用于创建新播放器）

我还有一个客户端类：

public class Cliente implements Runnable {

    String host;
    int puerto;
    Player mensaje;

public Cliente(int purto, Player mensaje, String host){
    this.puerto = purto;
    this.mensaje = mensaje;
    this.host = host;
}
@Override
public void run() {
    DataOutputStream out;

    try {
        Socket sc = new Socket(host, puerto);
        out = new DataOutputStream(sc.getOutputStream());
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(out);
        
        objectOutputStream.writeObject(mensaje);
        
        sc.close();

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

我正在使用 objectOutputStream 但它说它

“java.io.NotSerializableException：objects.Player”

我想将我的播放器发送到服务器，但它显示异常！

如果你需要这里还有服务器类

public class Servidor extends Observable implements Runnable {

    int puerto;

public Servidor(int puerto) {
    this.puerto = puerto;
}

@Override
public void run() {
    ServerSocket servidor = null;
    Socket sc = null;
    DataInputStream in;

    try {
        servidor = new ServerSocket(puerto);
        System.out.println("server started");

        while (true) {
            sc = servidor.accept();

            in = new DataInputStream(sc.getInputStream());
            ObjectInputStream input = new ObjectInputStream(in);

            Player players = null;
            try {
                players = (Player) input.readObject();
                System.out.println(players.Nombre);
            } catch (ClassNotFoundException ex) {
            }

            this.setChanged();
            this.notifyObservers(players);
            this.clearChanged();

            sc.close();
        }
    } catch (IOException ex) {
    }
}
}

如果你想要这里是发送请求到客户端类的代码行

    Cliente c = new Cliente(5000, new Player(x, y, width, height, icon, "name of the player"), "the ip");
    Thread t = new Thread(c);

    t.start();

Answer 1

看起来您忘记使 Player 对象可序列化，因此代码正在抛出 java.io.NotSerializableException

如果您需要通过网络发送一些对象，那么该对象需要是可序列化的。

序列化是获取一个内存数据结构的过程 对象并将其编码为一个串行（因此称为）序列 字节。然后可以将此编码版本保存到磁盘，通过 网络连接，或以其他方式传达给接收者。 （从 维基百科）

我已经更新了代码

Player.java

import java.io.Serializable;

import javax.swing.Icon;
import javax.swing.JLabel;

public class Player implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    public JLabel imagen;

    public String Nombre;

    public Player(int x, int y, int width, int height, Icon icono, String name) {
        imagen = Player(x, y, width, height, icono);
        Nombre = name;
    }

    public JLabel Player(int x, int y, int width, int height, Icon icono) {
        JLabel imagen = new JLabel(icono);
        imagen.setLocation(x, y);
        imagen.setSize(width, height);
        return imagen;
    }
}

Cliente.java

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.Socket;

public class Cliente implements Runnable {

    String host;
    int puerto;
    Player mensaje;

    public Cliente(int purto, Player mensaje, String host) {
        this.puerto = purto;
        this.mensaje = mensaje;
        this.host = host;
    }

//  @Override
    public void run() {
        DataOutputStream out;

        try {
            Socket sc = new Socket(host, puerto);
            out = new DataOutputStream(sc.getOutputStream());
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(out);

            objectOutputStream.writeObject(mensaje);

            sc.close();

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

    public static void main(String[] args) {
        Cliente c = new Cliente(5000, new Player(1, 2, 3, 4, null,
                "Holis Studios"), "localhost");
        Thread t = new Thread(c);

        t.start();
    }
}

Servidor.java

import java.io.DataInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Observable;

public class Servidor extends Observable implements Runnable {

    int puerto;

    public Servidor(int puerto) {
        this.puerto = puerto;
    }

//  @Override
    public void run() {
        ServerSocket servidor = null;
        Socket sc = null;
        DataInputStream in;

        try {
            servidor = new ServerSocket(puerto);
            System.out.println("server started");

            while (true) {
                sc = servidor.accept();

                in = new DataInputStream(sc.getInputStream());
                ObjectInputStream input = new ObjectInputStream(in);

                Player players = null;
                try {
                    players = (Player) input.readObject();
                    System.out.println(players.Nombre);
                } catch (ClassNotFoundException ex) {
                }

                this.setChanged();
                this.notifyObservers(players);
                this.clearChanged();

                sc.close();
            }
        } catch (IOException ex) {
        }
    }
    
    public static void main(String[] args) {
        Servidor server = new Servidor(5000);
        Thread t = new Thread(server);

        t.start();
    }
}

编译代码：

javac.exe -cp . Player.java

javac.exe -cp . Servidor.java

javac.exe -cp . Cliente.java

运行：

java.exe -cp . Servidor
server started

java.exe -cp . Cliente

出现在服务端控制台上的输出：

server started
Holis Studios