Bukkit 1.20.1 玩家放置大箱子发送消息插件

以下是一个使用Java编写的Bukkit插件，当玩家放置一个箱子并将其类型变为大箱子后，会发送一条消息给玩家。

import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.block.Block;
import org.bukkit.block.BlockState;
import org.bukkit.block.Chest;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.inventory.InventoryHolder;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.java.JavaPlugin;

public class ChestUpgradePlugin extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onBlockPlace(BlockPlaceEvent event) {
        Block placedBlock = event.getBlockPlaced();
        Player player = event.getPlayer();

        if (placedBlock.getType() == Material.CHEST) {
            BlockState blockState = placedBlock.getState();
            if (blockState instanceof Chest) {
                Chest chest = (Chest) blockState;
                if (chest.getInventory().getHolder() instanceof DoubleChestInventoryHolder) {
                    player.sendMessage(ChatColor.GREEN + '你放置了一个大箱子！');
                }
            }
        }
    }
}

请注意，上述代码假设您已经设置好Bukkit开发环境，并在您的项目中包含了Bukkit API的适当版本。