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全局变量值在可运行实现中是线程安全的?

spring-boot multithreading spring java

Faraz · 技术社区 · 5 年前

public class MyRunnable implements Runnable {

private String taskName;

private int executeCount = new Random().nextInt(10);

public MyRunnable(String taskName) {
    this.taskName = taskName;
}

@Override
public void run() {
    System.out.println(this.taskName + " in Thread ID: " + Thread.currentThread().getId() + ". execute count: " + ++executeCount);
}
}

我从10个线程开始并发运行代码。不知何故 executeCount 保持安全,我看到了预期值。

这是暂时的吗?每次我运行测试,它只是碰巧打印正确的值,但实际上它是不安全的?或者行为是预期的?

这是我的出发点:

@SpringBootApplication
@EnableScheduling
public class DynamicSchedularApplication implements ApplicationRunner {

public static void main(String[] args) {
    SpringApplication.run(DynamicSchedularApplication.class, args);
}

@Override
public void run(ApplicationArguments args) throws Exception {
    ThreadPoolTaskScheduler ts = threadPoolTaskScheduler();
    for (int i = 0; i < 10; i++) {
        ts.scheduleAtFixedRate(new MyRunnable("Task"+i),
            Duration.ofMillis(3000));
    }
}

@Bean
public ThreadPoolTaskScheduler threadPoolTaskScheduler() {
    ThreadPoolTaskScheduler ts = new ThreadPoolTaskScheduler();
    ts.setPoolSize(10);
    return ts;
}

}