多线程中使用单例

/**
 * @Author guozhan
 * @Date 2020/12/10 19:52
 *
 * 测试多线程的单例是否会互相干扰
 * 结论：会互相影响
 * 所以spring创建bean的时候要注意不必要的单例对象，或者说操作单例对象不要使用set
 */
public class SingletonTest {
    public static void main(String[] args) throws InterruptedException {
        Thread thread = new Thread(() -> {
            SingleUser singleUser = SingleUser.getInstance();
            singleUser.setId("1");
            System.out.println(singleUser.getId());
        });
        Thread thread1 = new Thread(() -> {
            SingleUser singleUser = SingleUser.getInstance();
            String id = singleUser.getId();
            System.out.println(id);
        });
        thread.start();
        TimeUnit.SECONDS.sleep(1);
        thread1.start();
    }
}

/**
 * @Author guozhan
 * @Date 2020/12/10 19:52
 */
@Data
public class SingleUser {
    private SingleUser() {
    }

    private String id;
    private static SingleUser singleUser = new SingleUser();

    public static SingleUser getInstance() {
        return singleUser;
    }
}