字段更新器

• AtomicReferenceFieldUpdater // 域 字段
• AtomicIntegerFieldUpdater
• AtomicLongFieldUpdater

:::tips 需要更改的属性必须用volatile 修饰！ :::

public class Test40 {
    public static void main(String[] args) {
        Student stu = new Student();
        AtomicReferenceFieldUpdater updater =
                AtomicReferenceFieldUpdater.newUpdater(Student.class, String.class, "name");
        System.out.println(updater.compareAndSet(stu, null, "张三"));
        System.out.println(stu);
    }
}
class Student {
    volatile String name;
    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                '}';
    }
}