如何使用套接字TCP在Java和Android之间正确传递对象？

Question

I am trying to send an object using TCP/IP using an Android application an a Java application. But I'm having the problem that the information coming is null.

The object belongs to a class called Mensaje, and in both projects has the same package name and have the same serialVersionUID:

package CLASSESS;

import java.io.Serializable;


public class Mensaje implements Serializable{
   // private static final long serialVersionUID = 5950169519310163575L;
   private static final long serialVersionUID = 9178463713495656548L;
    public static int TYPE;
    public static int ID;
    public static String DATA;
}

The Android application class implements Serializable and handles the conexion into a Threat

public class SocketClient implements Serializable{



private Runnable send_ObjectMessage = new Runnable(){
        public void run(){

            try {
                obj_Mensaje = new Mensaje();
                obj_Mensaje.TYPE = 1;
                obj_Mensaje.ID = 2;
                obj_Mensaje.DATA= "hOKA MUNDO";
                salida_mensaje = new ObjectOutputStream(socket_cliente.getOutputStream());
                salida_mensaje.writeObject(obj_Mensaje);
                salida_mensaje.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    };
}

The Server has the same Mensaje class and implements Serializable with the same serialVersionUID;

The server reads the object on a Threat.

@Override
public void run() {
    try {
        obj_message_read = new Mensaje();
        ois_readMessage = new ObjectInputStream(clientSocket.getInputStream());
        while(clientSocket.isConnected()){
            Object aux = ois_readMessage.readObject();
            if(aux instanceof Mensaje){
                obj_message_read = (Mensaje)aux;
                setDATA(obj_message_read.DATA);
                setTYPE(obj_message_read.TYPE);
                setID(obj_message_read.ID);
                System.out.println("Data" + obj_message_read.DATA);

            }
        }
    }catch (IOException ioe){
        ioe.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

}

The problem is that the information coming in the Mensaje is null. So when i print System.out.println("Data" + obj_message_read.DATA); the Server prints

Data Null

Answer 1

I think the problem is that the fields you are trying to send are declared as static , which are transient for serialization.

Change it removing that keyword:

public class Mensaje implements Serializable{
   // private static final long serialVersionUID = 5950169519310163575L;
   private static final long serialVersionUID = 9178463713495656548L;
    public int TYPE;
    public int ID;
    public String DATA;
}