我正在尝试创建一个简单的Socket Client-Server对，其中一个人会发送消息，但在我的一个run方法中，我这样做：String servermessage = new String(dis.readUTF());并返回java.io.EOFException什么是我做错了，有没有更好的方法在客户端和serversocket之间发送消息？
编辑：我现在知道当输入流到达所有字节之前的末尾时会发生EOFException，但我不明白它们的意思，有人可以澄清吗？
服务器：
public class Server {
String host = "localhost";
int port = 2484;
static boolean launched = false;
ServerSocket server;
static DataOutputStream dos;
public static void main(String args[]) throws IOException {
final Server serv = new Server();
final Thread socketThread = new Thread(new Runnable() {
ServerSocket server;
@Override
public void run() {
try {
Server serv = new Server();
ServerSocket server = new ServerSocket(serv.port);
System.out.println("Server: Launched!");
Socket client = server.accept();
OutputStream clientOut = client.getOutputStream();
DataOutputStream dos = new DataOutputStream(clientOut);
dos.close();
clientOut.close();
server.close();
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
Thread input = new Thread(new Runnable() { //Thread that reads from an input from the console
Server serv = new Server();
@Override
public void run() {
Scanner scanner = new Scanner(System.in);
System.out.println("Type Something!");
while (true) {
String input = scanner.next();
if (input.equalsIgnoreCase("Start")) {
if(!launched) { //Checks if the ServerSocket server is already launched, and if not, launches it
System.out.println("Launching the socket!");
socketThread.start();
input = scanner.next();
launched = true;
} else if(launched){
System.err.println("ServerSocket is already Launched!");
}
} else if (input.equalsIgnoreCase("Send")) {
System.out.println("What would you like to send?");
input = null;
input = scanner.next();
System.out.println("Server: " + input);
try {
dos.writeUTF(input); //Sends the input to the client
} catch (IOException e) {
System.err.println("Unable to send the message");
e.printStackTrace();
}
} else {
System.err.println("Unknown Input!");
input = null;
}
}
}
});
input.start();
}
}
SocketManager：
package Socket_Swing_Test_2;
public class SocketManager implements Runnable {
ClientMain c = new ClientMain();
ClientSwing cs = new ClientSwing();
Socket client;
PrintWriter output;
BufferedReader input;
InputStream clientIn;
DataInputStream dis;
String host = "localhost";
int port = 2484;
JTextArea textArea = cs.textArea;
public SocketManager(ClientMain c) {
this.c = c;
try {
client = new Socket(host, port);
System.out.println("SocketManager: Connected to the server!");
clientIn = client.getInputStream();
dis = new DataInputStream(clientIn);
} catch (Exception e) {
System.err.println("Client: Socket failed to Connect");
e.printStackTrace();
}
}
public synchronized void send(String message) {
try {
output.println(message);
output.flush();
} catch (Exception e) {
e.printStackTrace();
}
}
public synchronized void connect() {
try {
client = new Socket(host, port);
} catch (Exception e) {
System.err.println("Client: Socket failed to Connect");
e.printStackTrace();
}
}
public synchronized void close() {
try {
client.close();
} catch (Exception e) {
System.err.println("Unable to close the socket!");
e.printStackTrace();
}
clientIn = null;
dis = null;
System.gc(); // Garbage Collector, recycles unused objects that are taking up RAM
}
public synchronized boolean checkConnection() {
return client.isConnected();
}
public synchronized void listenStream() { //Unused, keeping for reference
try {
while (input.ready()) {
System.out.println(input.readLine());
}
} catch (Exception e) {
e.printStackTrace();
}
}
public synchronized Socket getSocket() {
return client;
}
public void receive() {
}
@Override
public void run() {
System.out.println("SocketManager.run: Is running!");
try {
//Read for a message from the server
System.out.println("SocketManager.run: Checking for messages from the server");
String servermessage = new String(dis.readUTF());
textArea.append(servermessage);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
client.close();
close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
你们可能不需要，但提供以防万一
ClientSwing：
public class ClientSwing extends JFrame {
JPanel panel;
JTextArea textArea;
JTextField textField;
int WIDTH = 640;
int HEIGHT = 480;
public ClientSwing() {
super("Client");
panel = new JPanel();
panel.setLayout(null);
textArea = new JTextArea();
textArea.setEditable(false);
textArea.setBounds(0, 0, WIDTH, HEIGHT - 15);
textArea.setFont(new Font("Impact", Font.PLAIN, 13 + 1/2));
textField = new JTextField();
textField.setLocation(0, HEIGHT - 47);
textField.setSize(WIDTH, 20);
textField.addActionListener(new ActionListener() { //I AM RIGHT HERE
@Override
public void actionPerformed(ActionEvent e) {
String input = textField.getText();
if(input.equalsIgnoreCase("Launch")) {
SwingWorker socketLaunch = new SwingWorker() {
@Override
protected Object doInBackground() throws Exception {
ClientMain main = new ClientMain();
main.run();
return null;
}
};
socketLaunch.execute();
}
}
});
panel.add(textArea);
panel.add(textField);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(WIDTH, HEIGHT);
setLocationRelativeTo(null);
setResizable(false);
add(textField);
add(textArea);
}
}
ClientMain：
public class ClientMain extends JFrame {
private SocketManager network;
int a = 1;
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ClientSwing window = new ClientSwing();
window.setVisible(true);
}
});
}
public void run() {
network = new SocketManager(new ClientMain());
Thread thread = new Thread(network);
thread.run();
}
public SocketManager getSocketM() {
return network;
}
}
追踪：
java.io.EOFException
at java.io.DataInputStream.readUnsignedShort(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at Socket_Swing_Test_2.SocketManager.run(SocketManager.java:114)
at java.lang.Thread.run(Unknown Source)
at Socket_Swing_Test_2.ClientMain.run(ClientMain.java:26)
at Socket_Swing_Test_2.ClientSwing$1$1.doInBackground(ClientSwing.java:46)
at javax.swing.SwingWorker$1.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at javax.swing.SwingWorker.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
答案 0 :(得分：1)
来自Data Streams的教程：
请注意
DataStreams通过捕获EOFException来检测文件结束条件，而不是测试无效的返回值。
数据流为原始数据值提供二进制I / O;没有任何方法可以阅读选择代表结束的价值。