在 Listener 类中注册事件

import org.bukkit.event.Listener;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerQuitEvent;

public class MyEventListener implements Listener {

    /**
     * Constructor
     */
    public MyEventListener(Main plugin){
        //register Events of this class
        //with methode: registerEvents(Listener, Plugin);
        plugin.getServer().getPluginManager().registerEvents(this, plugin);
    }      

    /**
     * A Event with HIGH priority
     */
    @EventHandler(priority = EventPriority.HIGH) //An EventHandler annotation
    public void onPlayerLogin(PlayerLoginEvent event){  //A bukkit event
        event.getPlayer().sendMessage("Welcome.");
    }
    /**
     * A Event with NORMAL (default) priority
     */
    @EventHandler    
    public void onPlayerQuit(PlayerQuitEvent event){ 
        Bukkit.broadcastMessage(event.getPlayer().getName() + " left the Server.");
    }
        

}

/**
 * Main class
 */
public class Main extends JavaPlugin {
    public void onEnable(){
        //Register Events
        new MyEventListener(this);
    }
}