Java中Semaphore控制资源访问方法

Semaphore semaphore = new Semaphore(3);

Semaphore semaphore = new Semaphore(3, true); // 公平模式

public class PrintJob implements Runnable {
    private Semaphore printerPool;
    
    public PrintJob(Semaphore printerPool) {
        this.printerPool = printerPool;
    }

    public void run() {
        try {
            System.out.println(Thread.currentThread().getName() + " 尝试获取打印机");
            printerPool.acquire(); // 获取许可
            System.out.println(Thread.currentThread().getName() + " 正在打印...");
            Thread.sleep(2000); // 模拟打印耗时
            System.out.println(Thread.currentThread().getName() + " 打印完成");
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        } finally {
            printerPool.release(); // 释放许可
        }
    }
}

Semaphore printerSemaphore = new Semaphore(2); // 只有2台打印机

for (int i = 1; i <= 5; i++) {
    Thread t = new Thread(new PrintJob(printerSemaphore), "线程-" + i);
    t.start();
}