Java并发工具类性能对比与案例解析

原创逃离我推掉我的手 2024-10-15 14:42 34阅读 0赞

Java并发工具类主要包括`java.util.concurrent`包中的各种类，如`ExecutorService`（线程池）、`Thread`、`CountDownLatch`、`Semaphore`等。

下面我们将通过性能对比和案例解析来展示这些工具的使用场景和性能特点：

1. **线程池对比：**`
    ExecutorService fixedThreadPool = Executors.newFixedThreadPool(5);
    ExecutorService queueThreadPool = Executors.newCachedThreadPool();

// 并发任务
    for (int i = 0; i < 10; i++) {
        fixedThreadPool.execute(() -> System.out.println("Fixed: " + i)));
        queueThreadPool.execute(() -> System.out.println("Caching: " + i)));
    }

// 关闭线程池
    fixedThreadPool.shutdown();
    queueThreadPool.shutdown();

// 确保所有任务完成
    while (!fixedThreadPool.isTerminated() || !queueThreadPool.isTerminated())) {
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
`
2. **案例解析：**使用`CountDownLatch`来协调多个线程的执行：

```java
import java.util.concurrent.CountDownLatch;

public class CountDownLatchExample {
    private final CountDownLatch countDownLatch = new CountDownLatch(3);

public void runThreads() {
        // 创建三个线程，每个线程增加计数器一次
        Thread thread1 = new Thread(() -> countDownLatch.countDown()));
        Thread thread2 = new Thread(() -> countDownLatch.countDown()));
        Thread thread3 = new Thread(() -> countDownLatch.countDown()));

// 启动线程
        thread1.start();
        thread2.start();
        thread3.start();

try {
            // 等待所有计数器下降到零
            countDownLatch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

public static void main(String[] args) {
        CountDownLatchExample example = new CountDownLatchExample();
        example.runThreads();
    }
}
```

通过上述对比和案例，我们可以了解到Java并发工具类在提高程序执行效率、控制线程数量等方面的优势。同时，理解并熟悉这些工具的使用方式和注意事项是提升编程技能的重要部分。