Discord Java bot通过名称验证用户

Question

in my current Discord (java) bot im trying to apply a command to a user name. how can i make sure this is an actual existing user ?

in psuedo code:

if User "A" exists {
User "A" types something at all
send message "hello"+ user "A"
}
else 
{
this is no valid user;
}

i can't figure out how to write the 'check if exist code'.

Answer 1

This is from JDA-Utilities which is a really useful tool when building discord bots.

import com.jagrosh.jdautilities.command.Command;
import com.jagrosh.jdautilities.command.CommandEvent;

public class Example extends Command {
    public Example() {
        this.name = "'isBot";
        this.help = "Tells you if the user is a bot!";
    }
    @Override
    protected void execute(CommandEvent e) {
        if (e.getAuthor().isBot()) {
            e.reply("Hey you're not a person!!");
        } else {
            e.reply("Hey " + e.getAuthor().getName() + ", you're not a bot!");
        }
    }
}