我有两个程序将在下面发布，一个是服务器，另一个是客户端。ChatServer运行一次，许多客户端可以从不同的计算机上运行ChatClient，并在GUI中一起交谈。客户端程序有两个按钮，一个模拟向单个用户发送消息；"向用户发送消息"，通常只是发送消息；"向所有人发送消息"。尽管现在服务器上的客户端似乎可以通过提供收件人名称来选择性地向个人发送消息，但所有客户端都可以看到该消息，这并不完全是我的目标。我要做的是点击"向用户发送消息"按钮，在所有其他用户都看不到消息的情况下向指定用户发送消息。
服务器程序代码
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
/**
* 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 ".
*
*/
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 ArrayList<String> names = new ArrayList<String>();
/**
* The set of all the print writers for all the clients. This
* set is kept so we can easily broadcast messages.
*/
private static ArrayList<PrintWriter> writers = new ArrayList<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) {
new Handler(listener.accept()).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 extends Thread {
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;
}
synchronized (names) {
if (!names.contains(name)) {
names.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);
// Accept messages from this client and broadcast them.
// Ignore other clients that cannot be broadcasted to.
while (true) {
String input = in.readLine();
if (input == null) {
return;
}
for (PrintWriter writer : writers) {
writer.println("MESSAGE " + name + ": " + input);
}
}
} 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) {
}
}
}
}
}
客户端程序代码
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;
import javax.swing.*;
/**
* 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("Chatter");
JTextField textField = new JTextField(40);
JTextArea messageArea = new JTextArea(8, 40);
JButton sendall = new JButton("Send Message to All");
JButton senduser = new JButton("Send Message to User");
String otherGuy = "";
/**
* 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, "South");
frame.getContentPane().add(new JScrollPane(messageArea), "Center");
frame.getContentPane().add(sendall, "West");
frame.getContentPane().add(senduser, "East");
frame.pack();
// Add Listeners
// 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("");
// }
// });
sendall.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("");
}
});
senduser.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.
*/
// = sendTo();
public void actionPerformed(ActionEvent e) {
otherGuy = sendTo();
out.println(textField.getText() + " -> " + otherGuy);
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() {
return JOptionPane.showInputDialog(
frame,
"Choose a screen name:",
"Screen name selection",
JOptionPane.PLAIN_MESSAGE);
}
private String sendTo() {
return JOptionPane.showInputDialog(
frame,
"Who do you want to send a message to?",
"",
JOptionPane.PLAIN_MESSAGE);
}
/**
* 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.
while (true) {
String line = in.readLine();
if (line.startsWith("SUBMITNAME")) {
out.println(getName() + otherGuy);
} 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.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
client.frame.setVisible(true);
client.run();
}
}
现在我已经尝试过拥有各种输入输出流并尝试连接它们，但没有成功。尝试过让名称数组列表将消息定向到一个客户端而不是所有客户端，但也没有成功。你们知道我该怎么做吗？
while (true) {
String input = in.readLine();
if (input == null) {
return;
}
for (PrintWriter writer : writers) {
writer.println("MESSAGE " + name + ": " + input);
}
}
} catch (IOException e) {
System.out.println(e);
}
这指定当服务器从客户端接收数据时，立即将其发送到所有输出流。没有过滤系统。如果只想将消息发送到1个客户端，则需要一种方法来指定要发送到哪个流。
当前协议：
Client sends - server receives - server sends to all connected outputstreams
所需协议：
Client sends - server receives - server see who message is too - server sends message to specified outputstream(s).