我有此代码示例，试图获取当前主机的详细信息。 我需要获取当前主机的JFrame标题（在其中设置了主机名）
之所以这样做，是因为我修改了程序，仅向其他客户端发送私人消息，因此该消息不会成为广播消息。
我使用了关键字“ 仅B ”，当您键入并发送该关键字时，只有名称为B的客户端/主机会收到此消息。
但是问题是消息没有显示在发送者的屏幕上，而是仅显示在接收者的屏幕上（即客户端“ B”）
我需要获取JFrame标题值（在其中设置了客户端的名称），以便我也可以在发件人的屏幕上显示消息。
还是我必须使用另一种方法？请让我知道。如何在Java套接字编程中获取当前主机的（发件人）名称？
这是我的ChatServer.java
import java.awt.Frame;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.HashSet;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
/**
* A multithreaded chat room server. When a client connects the
* server requests a screen name by sending the client the
* text "SUBMITNAME", and keeps requesting a name until
* a unique one is received. After a client submits a unique
* name, the server acknowledges with "NAMEACCEPTED". Then
* all messages from that client will be broadcast to all other
* clients that have submitted a unique screen name. The
* broadcast messages are prefixed with "MESSAGE ".
*
* Because this is just a teaching example to illustrate a simple
* chat server, there are a few features that have been left out.
* Two are very useful and belong in production code:
*
* 1. The protocol should be enhanced so that the client can
* send clean disconnect messages to the server.
*
* 2. The server should do some logging.
*/
public class ChatServer {
/**
* The port that the server listens on.
*/
private static final int PORT = 9001;
/**
* The set of all names of clients in the chat room. Maintained
* so that we can check that new clients are not registering name
* already in use.
*/
private static HashSet<String> names = new HashSet<String>();
private static HashSet<String> passedNames = new HashSet<String>();
/**
* The set of all the print writers for all the clients. This
* set is kept so we can easily broadcast messages.
*/
private static HashSet<PrintWriter> writers = new HashSet<PrintWriter>();
private static HashMap<String,PrintWriter> namesWithWriter = new HashMap<String,PrintWriter>();
/**
* The appplication main method, which just listens on a port and
* spawns handler threads.
*/
public static void main(String[] args) throws Exception {
System.out.println("The chat server is running.");
ServerSocket listener = new ServerSocket(PORT);
try {
while (true) {
Socket socket = listener.accept();
Thread handlerThread = new Thread(new Handler(socket));
handlerThread.start();
}
} finally {
listener.close();
}
}
/**
* A handler thread class. Handlers are spawned from the listening
* loop and are responsible for a dealing with a single client
* and broadcasting its messages.
*/
private static class Handler implements Runnable {
private String name;
private Socket socket;
private BufferedReader in;
private PrintWriter out;
/**
* Constructs a handler thread, squirreling away the socket.
* All the interesting work is done in the run method.
*/
public Handler(Socket socket) {
this.socket = socket;
}
/**
* Services this thread's client by repeatedly requesting a
* screen name until a unique one has been submitted, then
* acknowledges the name and registers the output stream for
* the client in a global set, then repeatedly gets inputs and
* broadcasts them.
*/
public void run() {
try {
// Create character streams for the socket.
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
out = new PrintWriter(socket.getOutputStream(), true);
// Request a name from this client. Keep requesting until
// a name is submitted that is not already used. Note that
// checking for the existence of a name and adding the name
// must be done while locking the set of names.
while (true) {
out.println("SUBMITNAME");
name = in.readLine();
if (name == null) {
return;
}
// TODO: Add code to ensure the thread safety of the
// the shared variable 'names'
synchronized (names) {
if (!names.contains(name)) {
names.add(name);
passedNames.add(name);
break;
}
}
}
// Now that a successful name has been chosen, add the
// socket's print writer to the set of all writers so
// this client can receive broadcast messages.
out.println("NAMEACCEPTED");
writers.add(out);
namesWithWriter.put(name,out);
// TODO: You may have to add some code here to broadcast all clients the new
// client's name for the task 9 on the lab sheet.
for(String key : namesWithWriter.keySet()){
if(key.equals(name)){
for(String name : names){
namesWithWriter.get(key).println("NEWNAME"+name);
}
}else{
namesWithWriter.get(key).println("NAME"+name);
}
}
// Accept messages from this client and broadcast them.
// Ignore other clients that cannot be broadcasted to.
while (true) {
String inputMessage = in.readLine();
if(inputMessage.startsWith("only") && inputMessage.trim().length()>4){
System.out.println("Specific User");
if (inputMessage == null) {
return;
}
System.out.println("Passed Names: "+passedNames);
String nameInTheInput = inputMessage.substring(5);
//System.out.println("Name in the Input "+nameInTheInput);
for(String key : namesWithWriter.keySet()) {
if(nameInTheInput.equalsIgnoreCase(key)) {
System.out.println("Send");
namesWithWriter.get(key).println("MESSAGE " + name + ": " + inputMessage+ " (only you and "+name+" can see this message)");
String hostName = socket.getInputStream().toString();
System.out.println("hostname is: "+hostName);
}else {
System.out.println("Don't send");
}
}
}else if(inputMessage.startsWith("all") && inputMessage.trim().length()>=3){ //to all the clients
System.out.println("All User");
for (PrintWriter writer : writers) {
writer.println("MESSAGE " + name + ": " + inputMessage);
}
}else{
System.out.println("No User");
//passedNames.add(inputMessage);
}
// TODO: Add code to send a message to a specific client and not
// all clients. You may have to use a HashMap to store the sockets along
// with the chat client names
}
}// TODO: Handle the SocketException here to handle a client closing the socket
catch (IOException e) {
System.out.println(e);
} finally {
// This client is going down! Remove its name and its print
// writer from the sets, and close its socket.
if (name != null) {
names.remove(name);
}
if (out != null) {
writers.remove(out);
}
try {
socket.close();
} catch (IOException e) {
}
}
}
}
}
这是我的* ChatClient.java **
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
/**
* A simple Swing-based client for the chat server. Graphically
* it is a frame with a text field for entering messages and a
* textarea to see the whole dialog.
*
* The client follows the Chat Protocol which is as follows.
* When the server sends "SUBMITNAME" the client replies with the
* desired screen name. The server will keep sending "SUBMITNAME"
* requests as long as the client submits screen names that are
* already in use. When the server sends a line beginning
* with "NAMEACCEPTED" the client is now allowed to start
* sending the server arbitrary strings to be broadcast to all
* chatters connected to the server. When the server sends a
* line beginning with "MESSAGE " then all characters following
* this string should be displayed in its message area.
*/
public class ChatClient {
BufferedReader in;
PrintWriter out;
JFrame frame = new JFrame();
JTextField textField = new JTextField(40);
JTextArea messageArea = new JTextArea(8, 40);
// TODO: Add a list box
/**
* Constructs the client by laying out the GUI and registering a
* listener with the textfield so that pressing Return in the
* listener sends the textfield contents to the server. Note
* however that the textfield is initially NOT editable, and
* only becomes editable AFTER the client receives the NAMEACCEPTED
* message from the server.
*/
public ChatClient() {
// Layout GUI
textField.setEditable(false);
messageArea.setEditable(false);
frame.getContentPane().add(textField, "North");
frame.getContentPane().add(new JScrollPane(messageArea), "Center");
frame.pack();
// TODO: You may have to edit this event handler to handle point to point messaging,
// where one client can send a message to a specific client. You can add some header to
// the message to identify the recipient. You can get the receipient name from the listbox.
textField.addActionListener(new ActionListener() {
/**
* Responds to pressing the enter key in the textfield by sending
* the contents of the text field to the server. Then clear
* the text area in preparation for the next message.
*/
public void actionPerformed(ActionEvent e) {
out.println(textField.getText());
textField.setText("");
}
});
}
/**
* Prompt for and return the address of the server.
*/
private String getServerAddress() {
return JOptionPane.showInputDialog(
frame,
"Enter IP Address of the Server:",
"Welcome to the Chatter",
JOptionPane.QUESTION_MESSAGE);
}
/**
* Prompt for and return the desired screen name.
*/
private String getName() {
String name = JOptionPane.showInputDialog(
frame,
"Choose a screen name:",
"Screen name selection",
JOptionPane.PLAIN_MESSAGE);
frame.setTitle("User "+name);
return name;
}
/**
* Connects to the server then enters the processing loop.
*/
private void run() throws IOException {
// Make connection and initialize streams
String serverAddress = getServerAddress();
Socket socket = new Socket(serverAddress, 9001);
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
out = new PrintWriter(socket.getOutputStream(), true);
// Process all messages from server, according to the protocol.
// TODO: You may have to extend this protocol to achieve task 9 in the lab sheet
while (true) {
String line = in.readLine();
if (line.startsWith("SUBMITNAME")) {
out.println(getName());
} else if (line.startsWith("NAMEACCEPTED")) {
textField.setEditable(true);
} else if (line.startsWith("MESSAGE")) {
messageArea.append(line.substring(8) + "\n");
}
}
}
/**
* Runs the client as an application with a closeable frame.
*/
public static void main(String[] args) throws Exception {
ChatClient client = new ChatClient();
client.frame.setLocationRelativeTo(null);
client.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
client.frame.setVisible(true);
client.run();
}
}