英文:
Object located in the main thread is not initialized by another thread
问题
我组合了一个客户端应用程序的类，它应该连接到一个套接字，并且应该自动从服务器检索一个DefaultTreeModel或一个简单的字符串对象作为测试。问题是，在主要的RemoteNetworking类内部，DefaultTreeModel或字符串成功地被接收，但是如果我尝试使用getClientTreeModel()或verifyFromOutside来获取它们，我只得到空对象。你能帮我理解这种行为吗？我将在下面放置代码。
package Networking;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.UnknownHostException;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class RemoteNetworking extends Thread{
private volatile Socket remoteSocket;
private volatile boolean isRunning = true;
private Thread currentThread;
private volatile ObjectOutputStream oos;
private volatile ObjectInputStream ois;
private volatile DefaultTreeModel treeModel = null;
private String IP;
private int port;
private static volatile String test;
public RemoteNetworking(String IP, int port) {
this.IP = IP;
this.port = port;
}
public void connect() {
try {
SocketAddress socketAddress = new InetSocketAddress(IP, port);
remoteSocket = new Socket();
remoteSocket.connect(socketAddress);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private synchronized void setReceivedTreeModel(DefaultTreeModel receivedTreeModel) {
this.treeModel = receivedTreeModel;
}
public synchronized void disconnect() {
try {
//oos.writeObject("Disconnect");
oos.flush();
//oos.close();
isRunning = false;
remoteSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public synchronized DefaultTreeModel getClientTreeModel() {
return treeModel;
}
public synchronized void verifyFromOutside() {
System.out.println(test);
}
@Override
public void run() {
connect();
synchronized(this) {
this.currentThread = Thread.currentThread();
}
try {
ois = new ObjectInputStream(remoteSocket.getInputStream());
oos = new ObjectOutputStream(remoteSocket.getOutputStream());
oos.writeObject("DataTree");
oos.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
while(isRunning) {
try {
Object object = (Object)ois.readObject();
/*if(object instanceof DefaultTreeModel) {
//this received object is not null
setReceivedTreeModel((DefaultTreeModel)object);
if(treeModel==null) {
System.out.println("Null object in RemoteNetworking");
}
verifyFromOutside();
}*/
if(object instanceof String) {
this.test = (String)object;
System.out.println(test);
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
英文:
I put together a class of an client app that should connect to a socket and it should automatically retrieve a DefaultTreeModel from the server or a simple String object as a test. The issue is that inside the main RemoteNetworking class the DefaultTreeModel or the String are successfully received but if I try to get them using getClientTreeModel() or verifiFromOutside i'm getting only null objects. Can you please help me understand this behavior? I'll place the code bellow.
package Networking;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.UnknownHostException;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class RemoteNetworking extends Thread{
private volatile Socket remoteSocket;
private volatile boolean isRunning = true;
private Thread currentThread;
private volatile ObjectOutputStream oos;
private volatile ObjectInputStream ois;
private volatile DefaultTreeModel treeModel = null;
private String IP;
private int port;
private static volatile String test;
public RemoteNetworking(String IP, int port) {
this.IP = IP;
this.port = port;
}
public void connect() {
try {
SocketAddress socketAddress = new InetSocketAddress(IP, port);
remoteSocket = new Socket();
remoteSocket.connect(socketAddress);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private synchronized void setReceivedTreeModel(DefaultTreeModel receivedTreeModel) {
this.treeModel = receivedTreeModel;
}
public synchronized void disconnect() {
try {
//oos.writeObject("Disconnect");
oos.flush();
//oos.close();
isRunning = false;
remoteSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public synchronized DefaultTreeModel getClientTreeModel() {
return treeModel;
}
public synchronized void verifyFromOutside() {
System.out.println(test);
}
@Override
public void run() {
connect();
synchronized(this) {
this.currentThread = Thread.currentThread();
}
try {
ois = new ObjectInputStream(remoteSocket.getInputStream());
oos = new ObjectOutputStream(remoteSocket.getOutputStream());
oos.writeObject("DataTree");
oos.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
while(isRunning) {
try {
Object object = (Object)ois.readObject();
/*if(object instanceof DefaultTreeModel) {
//this received object is not null
setReceivedTreeModel((DefaultTreeModel)object);
if(treeModel==null) {
System.out.println("Null object in RemoteNetworking");
}
verifyFromOutside();
}*/
if(object instanceof String) {
this.test = (String)object;
System.out.println(test);
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
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