从Java中的ObjectInputStream连续读取对象 [英] Continuously read objects from an ObjectInputStream in Java
问题描述
我在使用ObjectInputStream时遇到了问题，并且已经苦苦挣扎了2天.我试图寻找解决方案，但不幸的是找不到合适的答案.
I have a problem using an ObjectInputStream and I have been struggling with it for 2 days now. I tried to search for a solution but unfortunately found no fitting answer.
我正在尝试编写一个客户端/服务器应用程序，其中客户端将对象(在这种情况下为配置类)发送给服务器.这个想法是，连接在发送对象后保持活动状态，因此如有必要，可以发送新对象.
I am trying to write a client/server application in which the client sends objects (in this case a configuration class) to the server. The idea is that connection keeps alive after sending the object so it is possible to send a new object if necessary.
以下是我的客户代码的重要部分:
Here are the important parts of my client code:
mSocket = new Socket("192.168.43.56", 1234);
mObjectIn = new ObjectInputStream(mSocket.getInputStream());
mObjectOut = new ObjectOutputStream(mSocket.getOutputStream());
mObjectOut.writeObject(stubConfig);
mObjectOut.flush();
在上面的代码中，我省略了一些try/catch块来使您的代码可读.
In the above code, I left out some try/catch blocks to keep the code readable for you.
服务器端如下所示:
mHostServer = new ServerSocket(port);
mSocket = mHostServer.accept();
// create streams in reverse oreder
mObjectOut = new ObjectOutputStream(mConnection.getOutputStream());
mObjectOut.flush();
mObjectIn = new ObjectInputStream(mConnection.getInputStream());
while (mIsSocketConnected)
{
StubConfig = (StubConfiguration)mObjectIn.readObject();
}
我想要实现的是，只要套接字连接处于活动状态，服务器就在侦听传入的配置对象.
What I want to achieve is that as long at the socketconnection is alive, the server is listening for incoming config objects.
但是，当我运行程序时，服务器端的while循环中出现了EOFException.我在while循环的第一次迭代中收到第一个配置对象，没有任何问题，但是此后，每次调用readObject()时，我都得到一个EOFException.
When I run my program however, I got an EOFException in the while loop at server side. I receive the first config object without any problems in the first iteration of the while loop but after that I get an EOFException every time readObject() is called.
我正在寻找解决此问题的方法.谁能把我引向正确的方向?
I am looking for a way to solve this. Can anyone put me in the good direction?
我读到的关于EOFException的信息是，当您想从流中读取到它的结尾时，将抛出该EOFException.这意味着出于某种原因，流在对象已发送后结束.有没有办法重新初始化流??
What I read about the EOFException is that it is thrown when you want to read from a stream when the end of it is reached. That means that for some reason the stream ended after the object has been send. Is there a way to reinitialize the streams or so??
推荐答案
尝试使用此
try using this
服务器端
1.服务器在单独的线程上运行
Server side
1.Server running on a separate thread
public class ServeurPresence implements Runnable {
public final static int PORT = 20000 ;
public final static String HOSTNAME = "localhost" ;
public static enum Action {CONNEXION, MSG, DECONNEXION,USER, FINCLASSEMENT};
ServerSocket serveur ;
static List<String> names ;
*/
public ServeurPresence()
{
System.out.println("Start Server...");
try
{
serveur = new ServerSocket(PORT) ;
new Thread(this).start();
//javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI();} } );
}
catch (IOException e)
{
e.printStackTrace();
}
}
/**
* @param args
*/
public static void main(String[] args)
{
new ServeurPresence();
}
@Override
public void run()
{
System.out.println("server runs");
while(true)
{
try {
Socket sock = serveur.accept();
ServiceClientsThread thread= new ServiceClientsThread(sock);
thread.start();
}
catch (IOException e)
{
System.out.println("Error with socket");
e.printStackTrace();
}
}
}
}
2.一个用于处理每个Client:ServiceClientThread
2. A Thread to handle each Client:ServiceClientThread
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
public class ServiceClientsThread extends Thread{
private Socket sock ;
ServiceClientsThread(Socket sock)
{
//super();
this.sock=sock;
}
@Override
public void run()
{
DataInputStream is ;
DataOutputStream os ;
String name =null ;
try {
is = new DataInputStream(sock.getInputStream()) ;
os = new DataOutputStream(sock.getOutputStream()) ;
ServeurPresence.Action act ;
do {
// read Action
act = ServeurPresence.Action.valueOf(is.readUTF()) ; // read string -> enum
System.out.println("action :"+act);
switch (act) {
case CONNEXION :
name = is.readUTF(); //read client name
System.out.println("Name :"+name);
os.writeUTF("Hi");//send welcome msg
break ;
case MSG :
String msg = is.readUTF();
os.writeUTF("OK");//response
break ;
case DECONNEXION :
System.out.println(name+" is logged out");
break ;
}
} while (act!=ServeurPresence.Action.DECONNEXION) ;
// the end
is.close();
os.close();
sock.close();
} catch (IOException e)
{
System.out.println("Error with "+name+" socket");
e.printStackTrace();
}
}
}
3.客户端
3. Client side
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
public class Client {
/**
*
*/
Client(String name)
{
System.out.println("Start Client...");
try {
Socket sock = new Socket(ServeurPresence.HOSTNAME,ServeurPresence.PORT) ;
DataOutputStream os = new DataOutputStream(sock.getOutputStream()) ;
DataInputStream is = new DataInputStream(sock.getInputStream()) ;
System.out.println("Send "+name+" to server");
// CONNECTION : Action then value
os.writeUTF(ServeurPresence.Action.CONNEXION.name()) ; // send action : write enum -> String
os.writeUTF(name) ; // send the name
//read server welcome msg
String msg = is.readUTF();
System.out.println("Welcome msg: "+msg);
/* Your actions here : see example below */
try
{
Thread.currentThread().sleep(4000);
os.writeUTF(ServeurPresence.Action.MSG.name()) ; // send action : write enum -> String
os.writeUTF("My message here") ; // send msg
Thread.currentThread().sleep(4000);
msg = is.readUTF();//server response message
}
catch (InterruptedException e)
{
e.printStackTrace();
}
/************************************************/
//CLOSE
os.writeUTF(ServeurPresence.Action.DECONNEXION.name()) ; // send action
System.out.println("Log out");
os.close();
sock.close();
}
catch (UnknownHostException e)
{
System.out.println(ServeurPresence.HOSTNAME+ " unknown");
e.printStackTrace();
}
catch (IOException e)
{
System.out.println("Impossible to connect to "+ServeurPresence.HOSTNAME+ ":"+ServeurPresence.PORT);
e.printStackTrace();
}
}
}
4.在您的情况下，请使用readObject()/writeObject()而不是readUTF()/writeUTF()来写入您的配置对象
4. In your case use readObject()/writeObject() instead of readUTF()/writeUTF() to write your config objects
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