Java IRC登录缺少返回语句
我需要做IRC客户端,我有一个登录问题。我正在尝试通过服务器输入循环查找消息004或433,其中说明登录成功或登录正在使用。这是我的代码:`Java IRC登录缺少返回语句,java,chatbot,irc,Java,Chatbot,Irc,我需要做IRC客户端,我有一个登录问题。我正在尝试通过服务器输入循环查找消息004或433,其中说明登录成功或登录正在使用。这是我的代码:` import ecs100.*; import java.io.*; import java.net.Socket; import java.util.*; public class ChatClient { private String server = "irc.ecs.vuw.ac.nz"; private static final i
import ecs100.*;
import java.io.*;
import java.net.Socket;
import java.util.*;
public class ChatClient {
private String server = "irc.ecs.vuw.ac.nz";
private static final int IRC_PORT = 6667;
private static String nick;
private static String name;
private Socket socket;
private Scanner serverIn;
private PrintStream serverOut;
private String line;
private String channel;
// Constructor
public ChatClient (){
this.setupGUI();
}
public void setupGUI(){
UI.addButton("Connect", this::connect);
}
public void connect(){
try {
socket = new Socket(server,IRC_PORT);
serverIn = new Scanner(socket.getInputStream());
serverOut = new PrintStream(socket.getOutputStream());
UI.println("login");
this.login();
UI.println("listening");
this.listenToServer();
}catch(IOException e){UI.println("IO failure "+ e);}
}
private boolean login(){
String username = UI.askToken("Enter your usercode: ");
String realname = UI.askString("Enter your real name: ");
this.nick = username;
this.name = realname;
send("NICK " + username);
send("USER " + username + " 0 unused :" + realname);
UI.println("listening to server");
while(this.serverIn.hasNext()){
this.line = serverIn.nextLine();
UI.println("SERVER" + line);
if (line.indexOf("004") >= 0){
UI.println("true");
return true;
} else if(line.indexOf("433") >= 0){
UI.println("failed to connect, username already in use");
return false;
} else {
UI.println("else");
return false;
}
}
}
private void send(String msg){
serverOut.print(msg + "\r\n");
serverOut.flush();
}
private void listenToServer() {
while(this.serverIn.hasNext()){
String line = serverIn.nextLine();
UI.println("SERVER" + line);
if(line.equals("SQUIT")){
this.closeConnection();
}
if(line.equals("PING")){
String pingMsg = line.split(" ",2)[1];
this.send("PONG " + pingMsg);
}
}
}
public void closeConnection(){
try {
this.socket.close();
this.serverIn.close();
this.serverOut.close();
UI.println("Closed");
} catch(IOException e){UI.println("IO failure "+ e);}
}
public void joinChannel(){
String channel = UI.askString("Enter channel name: ");
send("JOIN " + channel);
}
public void leaveChannel(){
send("PART " + channel);
}
public static void main(String[] args) {
new ChatClient();
}
}
问题是它在login方法中不断抛出缺少的return语句。谁能看看我的代码,看看这里有什么问题吗
编辑:
所以当我将if语句改为两个if,并将return false放在循环之外时,程序工作了。有人能解释为什么while循环中的if/else语句不起作用吗
private boolean login(){
String username = UI.askToken("Enter your usercode: ");
String realname = UI.askString("Enter your real name: ");
this.nick = username;
this.name = realname;
send("NICK " + username);
send("USER " + username + " 0 unused :" + realname);
UI.println("listening to server");
while(this.serverIn.hasNext()){
this.line = serverIn.nextLine();
UI.println("SERVER" + line);
if (line.indexOf("004") >= 0){
UI.println("true");
return true;
}
if(line.indexOf("433") >= 0){
UI.println("failed to connect, username already in use");
return false;
}
}
UI.println("else");
return false;
}
enter code here
因为有一个代码路径会导致调用no
return
,而对于非void方法,编译器不允许这样做
如果this.serverIn.hasNext()
返回false,如果结尾没有return语句,该方法将返回什么?毕竟,它需要返回一个布尔值
程序逻辑可能被编写成永远不会使用特定的代码路径,但理论上是可能的,这就是编译器抱怨的原因