java如何停止多线程聊天客户端
我正在尝试使用Java创建一个多线程聊天客户端服务器。我用这个教程作为开始：http://pguides.net/java-tutorial/java-tcp-clientserver-chat/
当我输入字符串“quit”时，我希望客户端停止，但我不明白该如何做。此外，当客户端断开连接时，我需要将客户端从已连接的nick列表中删除
服务器
/* ChatServer.java */
import java.net.ServerSocket;
import java.net.Socket;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Hashtable;
public class ChatServer {
private static int port = 1001;
public static void main (String[] args) throws IOException {
ServerSocket server = null;
try {
server = new ServerSocket(port);
} catch (IOException e) {
System.err.println("Could not listen on port: " + port);
System.err.println(e);
System.exit(1);
}
Socket client = null;
while(true) {
try {
client = server.accept();
} catch (IOException e) {
System.err.println("Accept failed.");
System.err.println(e);
System.exit(1);
}
/* start a new thread to handle this client */
Thread t = new Thread(new ClientConn(client));
t.start();
}
}
}
class ChatServerProtocol {
private String nick;
private ClientConn conn;
private static Hashtable<String, ClientConn> nicks = new Hashtable<String, ClientConn>();
private static final String msg_OK = "OK";
private static final String msg_INVALID = "INVALID COMMAND";
private static final String msg_SEND_FAILED = "FAILED TO SEND";
private static boolean add_nick(String nick, ClientConn c) {
if (nicks.containsKey(nick)) {
return false;
} else {
nicks.put(nick, c);
return true;
}
}
private static boolean remove_nick(String nick, ClientConn c) {
if (!(nicks.containsKey(nick))) {
return false;
} else {
nicks.remove(nick);
return true;
}
}
public ChatServerProtocol(ClientConn c) throws IOException {
nick = null;
conn = c;
}
private boolean sendMsg(String recipient, String msg) {
if (nicks.containsKey(recipient)) {
ClientConn c = nicks.get(recipient);
c.sendMsg(nick + ": " + msg);
return true;
} else {
return false;
}
}
public String process(String msg) {
if (msg.startswith("Nick"){
String output = "";
if(add_nick(tryauthor, this.conn)) {
this.nick = tryauthor;
output = "Welcome "+tryauthor;
} else {
output = "Nick already in";
}
}
}
else if (msg.startsWith("msg")) {
String[] msg_parts = msg.split(":");
for(int i=0; i<msg_parts.length; i++){
System.out.println(msg_parts[i]);
}
String msg_type = msg_parts[0];
if(msg_type.equals("msg")) {
if(msg_parts.length < 3) output = msg_INVALID;
if(sendMsg(msg_parts[1], msg_parts[2])) output = msg_OK;
else output = msg_SEND_FAILED;
} else {
output = msg_INVALID;
}
}
return output;
}
}
class ClientConn implements Runnable {
private Socket client;
private BufferedReader in = null;
private PrintWriter out = null;
public ClientConn(Socket client) {
this.client = client;
try {
/* obtain an input stream to this client ... */
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
/* ... and an output stream to the same client */
out = new PrintWriter(client.getOutputStream(), true);
} catch (IOException e) {
System.err.println(e);
return;
}
}
public void run() {
String msg, response;
try {
ChatServerProtocol protocol = new ChatServerProtocol(this);
/* loop reading lines from the client which are processed
* according to our protocol and the resulting response is
* sent back to the client */
while ((msg = in.readLine()) != "quit\r\n") {
response = protocol.process(msg);
out.println("SERVER: " + response);
}
this.close();
} catch (IOException e) {
System.err.println(e);
}
}
public void sendMsg(String msg) {
out.println(msg);
}
public void close() throws IOException {
in.close();
out.close();
client.close();
}
}
客户
/* ChatClient.java */
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
public class ChatClient {
private static int port = 1001;
private static String host = "localhost";
private static BufferedReader stdIn;
public static void main (String[] args) throws IOException {
Socket server = null;
try {
server = new Socket(host, port);
} catch (UnknownHostException e) {
System.err.println(e);
System.exit(1);
}
stdIn = new BufferedReader(new InputStreamReader(System.in));
PrintWriter out = new PrintWriter(server.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader(server.getInputStream()));
System.out.print("Nick: ");
String auth = stdIn.readLine();
out.println("Nick: " + auth);
String serverResponse = in.readLine();
System.out.println(serverResponse);
if (serverResponse.startsWith("SERVER: welcome")) {
/* create a thread to asyncronously read messages from the server */
ServerConn sc = new ServerConn(server);
Thread t = new Thread(sc);
t.start();
String msg;
/* loop reading messages from stdin and sending them to the server */
while ((msg = stdIn.readLine()) != "quit\r\n") {
out.println(msg);
}
sc.close();
System.out.println("Exit.");
System.out.println("---Client Error---");
}
else {
System.out.println("Exit.");
System.out.println("---Client Error---");
}
}
}
class ServerConn implements Runnable {
private BufferedReader in = null;
private Socket server;
public ServerConn(Socket s) throws IOException {
server = s;
in = new BufferedReader(new InputStreamReader(s.getInputStream()));
}
public void run() {
String msg;
try {
/* loop reading messages from the server and show them
* on stdout */
while ((msg = in.readLine()) != "quit\r\n") {
System.out.println(msg);
}
this.close();
} catch (IOException e) {
System.err.println(e);
}
}
public void close() throws IOException {
in.close();
server.close();
}
}
我应该在哪里以及如何关闭连接
# 1 楼答案
您可以使用
System.exit(status)立即终止当前的Java程序。由于操作系统会在进程终止时自动释放进程获取的所有资源（如tcp套接字），因此也会关闭连接这更难。请记住，发生断开连接的原因可能不是客户端终止，例如，因为网线已拔出。也就是说，客户端无法可靠地通知服务器它已经不在了，服务器必须自己检测到这一点。我希望服务器操作系统的tcp实现能够检测到客户机已不在那里（速度可能取决于实现），并向使用该套接字的应用程序抛出异常，您可以捕获该套接字并将其从列表中删除