每个玩家的数据

读取身份键 · 位置见本节说明

UUID id = player.getUniqueId();
String displayName = player.getName();

合适的字段类型 · 位置见本节说明

private final Map<UUID, Integer> mined = new HashMap<>();

累计开采次数 · 位置见本节说明

UUID id = player.getUniqueId();
mined.merge(id, 1, Integer::sum);
int count = mined.getOrDefault(id, 0);

新玩家默认零 · 位置见本节说明

UUID other = UUID.randomUUID(); // 只用于本地练习
System.out.println(mined.getOrDefault(other, 0));

运行结果

0

计算截止时间 · 位置见本节说明

long now = System.currentTimeMillis();
long readyAt = now + 30_000L;
boolean cooling = now < readyAt;

统一时间单位 · 位置见本节说明

long durationMs = 30_000L; // 30秒，不是30毫秒
long threeSeconds = 3L * 1000L;

剩余时间不小于零 · 位置见本节说明

long remainingMs = Math.max(0L, readyAt - now);

整数向上取整 · 位置见本节说明

long seconds = (remainingMs + 999L) / 1000L;

完整 Cooldowns 类 · 完整文件

package de.teacherma.lesson34;

import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

public final class Cooldowns {
    private final Map<UUID, Long> readyAt = new HashMap<>();
    public long remaining(UUID id, long now) {
        return Math.max(0L, readyAt.getOrDefault(id, now) - now);
    }
    public void start(UUID id, long now, long durationMs) {
        if (durationMs < 0) throw new IllegalArgumentException("冷却不能为负");
        readyAt.put(id, now + durationMs);
    }
    public long seconds(UUID id, long now) {
        long ms = remaining(id, now);
        return (ms + 999L) / 1000L;
    }
    public void prune(long now) {
        readyAt.entrySet().removeIf(entry -> entry.getValue() <= now);
    }
    public void clear() { readyAt.clear(); }
}

两个玩家的边界测试 · 位置见本节说明

Cooldowns c = new Cooldowns();
UUID alex = UUID.randomUUID();
UUID steve = UUID.randomUUID();
c.start(alex, 1000L, 30_000L);
System.out.println(c.remaining(alex, 1000L));
System.out.println(c.remaining(alex, 30999L));
System.out.println(c.seconds(alex, 30999L));
System.out.println(c.remaining(alex, 31000L));
System.out.println(c.remaining(steve, 2000L));

运行结果

30000
1
1
0
0

防止归一化零向量 · 位置见本节说明

Vector direction = player.getLocation().getDirection().setY(0);
if (direction.lengthSquared() < 0.0001) {
    player.sendMessage(Component.text("请平视前方再冲刺"));
    return true;
}

给玩家一次速度 · 位置见本节说明

player.setVelocity(direction.normalize().multiply(0.9).setY(0.2));

使用同一份现在时间 · 位置见本节说明

long now = System.currentTimeMillis();
if (cooldowns.remaining(id, now) > 0) {
    player.sendMessage(Component.text(
            "再等 " + cooldowns.seconds(id, now) + " 秒"));
    return true;
}

成功路径末尾 · 位置见本节说明

player.setVelocity(direction.normalize().multiply(0.9).setY(0.2));
cooldowns.start(id, now, 30_000L);

懒清理 · 位置见本节说明

long now = System.currentTimeMillis();
cooldowns.prune(now);

停用时清空 · 位置见本节说明

@Override
public void onDisable() {
    cooldowns.clear();
}

完整 plugin.yml · 完整文件

name: BlockAcademyL34
version: 1.0.0
main: de.teacherma.lesson34.DashPlugin
api-version: '1.21.11'
author: TeacherMa
website: https://www.teacher-ma.de
commands:
  dash:
    description: 向前冲刺
    usage: /dash
permissions:
  blockacademy.dash:
    default: true

DashPlugin 第1部分 · 顺序接在同一源文件

package de.teacherma.lesson34;

import java.util.Objects;
import net.kyori.adventure.text.Component;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.util.Vector;

public final class DashPlugin extends JavaPlugin {
    private final Cooldowns cooldowns = new Cooldowns();
    @Override
    public void onEnable() {
        Objects.requireNonNull(getCommand("dash")).setExecutor(this);
    }
    @Override
    public boolean onCommand(CommandSender sender, Command command,
                             String label, String[] args) {
        if (!(sender instanceof Player player)) {
            sender.sendMessage("冲刺需要游戏中的身体");
            return true;
        }
        if (!player.hasPermission("blockacademy.dash")) {
            player.sendMessage(Component.text("你还没有冲刺权限"));
            return true;
        }
        if (args.length != 0) {
            player.sendMessage(Component.text("用法：/dash"));
            return true;
        }

DashPlugin 第2部分 · 顺序接在同一源文件

        long now = System.currentTimeMillis();
        cooldowns.prune(now);
        var id = player.getUniqueId();
        if (cooldowns.remaining(id, now) > 0) {
            player.sendMessage(Component.text(
                    "再等 " + cooldowns.seconds(id, now) + " 秒"));
            return true;
        }
        Vector direction = player.getLocation().getDirection().setY(0);
        if (direction.lengthSquared() < 0.0001) {
            player.sendMessage(Component.text("请平视前方再冲刺"));
            return true;
        }
        player.setVelocity(direction.normalize().multiply(0.9).setY(0.2));
        cooldowns.start(id, now, 30_000L);
        player.sendMessage(Component.text("冲刺！下次需要等30秒"));
        return true;
    }
    @Override
    public void onDisable() { cooldowns.clear(); }
}

L34RuleCheck.java · 完整文件

import de.teacherma.lesson34.Cooldowns;
import java.util.UUID;

public class L34RuleCheck {
    public static void main(String[] args) {
        Cooldowns c = new Cooldowns();
        UUID alex = new UUID(0, 1), steve = new UUID(0, 2);
        c.start(alex, 1000L, 30_000L);
        System.out.println(c.remaining(alex, 1000L));
        System.out.println(c.remaining(alex, 30999L));
        System.out.println(c.seconds(alex, 30999L));
        System.out.println(c.remaining(alex, 31000L));
        System.out.println(c.remaining(steve, 2000L));
    }
}

运行结果

30000
1
1
0
0

checks/sources.txt · 完整内容

src/main/java/de/teacherma/lesson34/Cooldowns.java
checks/L34RuleCheck.java

项目根目录终端命令 · 分别执行两行

javac -encoding UTF-8 -d checks/out @checks/sources.txt
java -cp checks/out L34RuleCheck