class Task implements Comparable<Task> {
    private String name;
    private int priority; // 数值越小，优先级越高
    private long executeTime;

    public Task(String name, int priority, long executeTime) {
        this.name = name;
        this.priority = priority;
        this.executeTime = executeTime;
    }

    @Override
    public int compareTo(Task other) {
        return Integer.compare(this.priority, other.priority); // 优先级小的排前面
    }

    @Override
    public String toString() {
        return "Task{name='" + name + "', priority=" + priority + ", executeTime=" + executeTime + "}";
    }
}

import j*a.util.PriorityQueue;

public class TaskScheduler {
    public static void main(String[] args) {
        PriorityQueue<Task> taskQueue = new PriorityQueue<>();

        // 添加任务
        taskQueue.offer(new Task("发送邮件", 3, System.currentTimeMillis() + 1000));
        taskQueue.offer(new Task("保存日志", 1, System.currentTimeMillis() + 500));
        taskQueue.offer(new Task("处理订单", 2, System.currentTimeMillis() + 800));

        // 按优先级执行任务
        while (!taskQueue.isEmpty()) {
            Task task = taskQueue.poll(); // 取出优先级最高的任务
            System.out.println("执行: " + task);
        }
    }
}

执行: Task{name='保存日志', priority=1, executeTime=...}
执行: Task{name='处理订单', priority=2, executeTime=...}
执行: Task{name='发送邮件', priority=3, executeTime=...}

PriorityQueue<Task> queue = new PriorityQueue<>((t1, t2) -> 
    Long.compare(t1.getExecuteTime(), t2.getExecuteTime())
);