问题描述
目的是将坐标从一个客户端（正在绘制）传输到所有连接到服务器的客户端，然后在各自的面板上绘制，但客户端中的 readobject() 似乎从未获取数据。输入确实正确发送到服务器，但来自服务器，其他客户端无法收听。
当使用 BufferedStream 或 DataInput/OutputStream any Other 时，输入似乎滞后或行为不端。所以更喜欢ObjectOutputStream。 Snapshot of the Program.
客户端在后台线程 listenData 中监听输入。
客户端代码 -
公共类客户端扩展 JFrame {
private static final long serialVersionUID = 1L;
private Coordinates crdntsToSend;
private Coordinates crdntsReceived;
private JPanel contentPane;
private Socket socket;
private ObjectOutputStream toServerPipe;
private ObjectInputStream fromServerPipe;
private JPanel paintPanel;
public Clients(String name,int port,String ip) {
setResizable(false);
setTitle("Skribbl");
setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
setSize(600,550);
createConnection(ip,port);
listen();
}
private void createConnection(String ip,int port)
{
try {
socket = new Socket(ip,port);
toServerPipe = new ObjectOutputStream(socket.getoutputStream());
fromServerPipe = new ObjectInputStream(socket.getInputStream());
toServerPipe.flush();
userInterfaceSetter();
} catch (IOException e) {
System.out.println("Port Not Found!!!");
return;
}
}
private void userInterfaceSetter()
{
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e1) {
e1.printstacktrace();
}
getContentPane().setLayout(null);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5,5,5));
setContentPane(contentPane);
GridBagLayout gbl_contentPane = new GridBagLayout();
gbl_contentPane.columnWidths = new int[] {0,0};
gbl_contentPane.rowHeights = new int[]{0,0};
gbl_contentPane.columnWeights = new double[]{1.0,Double.MIN_VALUE};
gbl_contentPane.rowWeights = new double[]{1.0,0.0,Double.MIN_VALUE};
contentPane.setLayout(gbl_contentPane);
paintPanel = new JPanel();
paintPanel.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
drawOnPanel(e.getX(),e.getY());
}
});
paintPanel.addMouseMotionListener(new MouseMotionAdapter() {
@Override
public void mouseDragged(MouseEvent e) {
drawOnPanel(e.getX(),e.getY());
}
});
paintPanel.setBackground(new Color(175,238,238));
GridBagConstraints gbcPaintPanel = new GridBagConstraints();
gbcPaintPanel.insets = new Insets(10,10,10);
gbcPaintPanel.fill = GridBagConstraints.BOTH;
gbcPaintPanel.gridx = 0;
gbcPaintPanel.gridy = 0;
contentPane.add(paintPanel,gbcPaintPanel);
JLabel lblscore = new JLabel("score: ");
GridBagConstraints gbclblscore = new GridBagConstraints();
gbclblscore.insets = new Insets(0,0);
gbclblscore.anchor = GridBagConstraints.WEST;
gbclblscore.gridx = 0;
gbclblscore.gridy = 1;
contentPane.add(lblscore,gbclblscore);
}
private void drawOnPanel(int x,int y)
{
Graphics g = paintPanel.getGraphics();
g.filloval(x,y,7,7);
sendData(x,y);
}
private void sendData(int x,int y) {
try {
crdntsToSend = new Coordinates(x,y);
toServerPipe.writeObject(crdntsToSend);
toServerPipe.flush();
} catch (IOException e) {
e.printstacktrace();
}
}
private void listen()
{
SwingWorker<Void,String> listenData = new SwingWorker<Void,String>() {
boolean go = true;
String[] receivedData;
String str;
@Override
protected Void doInBackground() throws Exception {
while(go)
{
crdntsReceived = (Coordinates) fromServerPipe.readobject();
str= crdntsReceived.toString();
publish(str);
}
return null;
}
@Override
protected void process(List<String> chunks) {
receivedData = str.split(" ");
drawOnPanel(Integer.parseInt(receivedData[0]),Integer.parseInt(receivedData[1]));
}
};
listenData.execute();
}
}
ServerHandler 代码（服务器线程）-
package theskribbl;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.socket;
public class HandleClient implements Runnable
{
private Socket[] socket;
private ObjectInputStream fromClients;
private ObjectOutputStream toClients;
private static int count = 0;
private int temp;
public HandleClient(Socket[] socket,int count)
{
HandleClient.count = count;
temp=count;
this.socket=socket;
try
{
fromClients = new ObjectInputStream(socket[count].getInputStream());
toClients = new ObjectOutputStream(socket[count].getoutputStream());
toClients.flush();
}
catch (IOException e)
{
e.printstacktrace();
}
}
@Override
public void run()
{
int i;
Coordinates coordinate;
while(true)
{
i=0;
try
{
coordinate = (Coordinates) fromClients.readobject();
System.out.println(coordinate.toString());
while(i<=count)
{
if(i!=temp)
{
toClients = new ObjectOutputStream(socket[i].getoutputStream());
toClients.writeObject(coordinate);
toClients.flush();
}
i++;
}
}
catch (Exception e)
{
System.out.println("Something Went Wrong");
return;
}
}
}
}
客户代码 - https://repl.it/@GirirajSingh/skribbl#Clients.java
登录客户端的代码 - https://repl.it/@GirirajSingh/skribbl#Login.java
处理客户端（服务器端）的代码 - https://repl.it/@GirirajSingh/skribbl#HandleClient.java
服务器代码 - https://repl.it/@GirirajSingh/skribbl#ServerClass.java
解决方法
ObjectOutputStream 和 ObjectInputStream 构造函数调用必须匹配 - 创建 ObjectOutputStream 时，它会发送一个标头，在创建 ObjectInputStream 时必须接收该标头。
我没有时间研究代码，但看起来每次服务器发送内容时，输出流都是在循环中构建的。客户每次收到坐标时都会重新打开输入吗？
查看 ObjectOutputStream 和 ObjectInputStream 的文档以获得更好的解释。最好从一个（非常）简单的原型开始：一个服务器，一个客户端，然后只发送几个（测试 = 固定）坐标。
doInBackGround() 可能抛出了一个异常（在 SwingWorker 内）！建议通过在 get() 终止后（在其覆盖的 SwingWorker 内）调用 done() 方法来检查这一点 - 如果计算抛出异常，这将抛出一个 ExecutionException ，其中将包含有关异常的信息。
在 SwingWorker 中添加一些类似如下的代码：
@Override
protected void done() {
try {
get();
} catch (Exception ex) {
ex.printStackTrace();
}
}
注意：这段代码不是为了解决问题，只是为了显示一个可能的错误
,您所说的标头不匹配，实际上它们是匹配的，因为它们是通过同一个 Socket 初始化的。 同样的过程使用 DataOutputStream/DataInputStream(write()/read() ) 工作，但在这个过程中数据正在泄漏，因为如果鼠标快速拖动，数据会在两者之间丢失。所以这就是我想使用 ObjectOutputStream 的 read/writeObject() 的原因。