Java中，有用户加入群组，telegram机器人如何获取进群链接 请使用Java代码实现

首先，需要使用Telegram Bot API，具体步骤如下：

1. 获取Bot Token，在BotFather处创建机器人并获取Token。

2. 获取群组ID，在机器人中发送一条消息到群组中，然后使用getUpdates API获取消息更新，从返回的JSON数据中获取群组ID。

3. 通过群组ID获取群组信息，包括群组成员列表和邀请链接。

4. 监听群组成员变化，当有新成员加入群组时，使用getChatMember API获取新成员信息，从中获取用户ID和用户名。

Java代码实现如下：

import org.telegram.telegrambots.ApiContextInitializer;
import org.telegram.telegrambots.meta.TelegramBotsApi;
import org.telegram.telegrambots.meta.api.methods.groupadministration.GetChatMember;
import org.telegram.telegrambots.meta.api.methods.groupadministration.GetChatMemberCount;
import org.telegram.telegrambots.meta.api.methods.groupadministration.GetChatMembersCount;
import org.telegram.telegrambots.meta.api.methods.groupadministration.GetChatMembersCount;
import org.telegram.telegrambots.meta.api.methods.invite.CreateChatInviteLink;
import org.telegram.telegrambots.meta.api.methods.updates.GetUpdates;
import org.telegram.telegrambots.meta.api.objects.Chat;
import org.telegram.telegrambots.meta.api.objects.ChatMember;
import org.telegram.telegrambots.meta.api.objects.Update;
import org.telegram.telegrambots.meta.api.objects.User;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;
import org.telegram.telegrambots.updatesreceivers.DefaultBotSession;
import java.util.List;

public class TelegramBot {
    public static void main(String[] args) {
        ApiContextInitializer.init();
        try {
            TelegramBotsApi telegramBotsApi = new TelegramBotsApi(DefaultBotSession.class);
            telegramBotsApi.registerBot(new MyBot());
        } catch (TelegramApiException e) {
            e.printStackTrace();
        }
    }

    private static class MyBot extends org.telegram.telegrambots.bots.TelegramLongPollingBot {
        @Override
        public void onUpdateReceived(Update update) {
            if (update.hasMessage() && update.getMessage().hasText()) {
                String messageText = update.getMessage().getText();
                long chatId = update.getMessage().getChatId();
                if (messageText.equals("/invite_link")) {
                    try {
                        // 获取群组信息
                        GetChatMembersCount getChatMembersCount = new GetChatMembersCount();
                        getChatMembersCount.setChatId(chatId);
                        int membersCount = execute(getChatMembersCount);
                        CreateChatInviteLink createChatInviteLink = new CreateChatInviteLink();
                        createChatInviteLink.setChatId(chatId);
                        createChatInviteLink.setMemberLimit(membersCount + 1);
                        String inviteLink = execute(createChatInviteLink).getInviteLink();

                        // 发送邀请链接
                        execute(new SendMessage(chatId, inviteLink));
                    } catch (TelegramApiException e) {
                        e.printStackTrace();
                    }
                }
            } else if (update.hasMessage() && update.getMessage().getNewChatMembers() != null) {
                // 新成员加入群组
                List<User> newChatMembers = update.getMessage().getNewChatMembers();
                for (User user : newChatMembers) {
                    try {
                        GetChatMember getChatMember = new GetChatMember();
                        getChatMember.setChatId(update.getMessage().getChatId());
                        getChatMember.setUserId(user.getId());
                        ChatMember chatMember = execute(getChatMember);
                        System.out.println("New member joined: " + chatMember.getUser().getUserName());
                    } catch (TelegramApiException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

        @Override
        public String getBotUsername() {
            return "your_bot_username";
        }

        @Override
        public String getBotToken() {
            return "your_bot_token";
        }
    }
}