前言：
在java5以后，我们接触到了线程原子性操作，也就是在修改时我们只需要保证它的那个瞬间是安全的即可，经过相应的包装后可以再处理对象的并发修改，本文总结一下Atomic系列的类的使用方法，其中包含：
1. 基本类型的使用
public class AtomicTest {
public static void main(String[] args) {
final AtomicTicket ticket = new AtomicTicket();
for (int i = 0; i < 3; i++) {
new Thread(new Runnable() {
@Override
public void run() {
while (ticket.getCount() > 0) {
System.out.println(Thread.currentThread().getName() + " count: " + ticket.decrement());
}
}
}).start();
}
}
}
class AtomicTicket {
public AtomicInteger count = new AtomicInteger(100);
public int decrement() {
return count.getAndDecrement();
}
public int getCount() {
return count.get();
}
}
Thread-0 count: 100
Thread-2 count: 98
Thread-1 count: 99
Thread-2 count: 96
Thread-0 count: 97
Thread-2 count: 94
Thread-2 count: 92
Thread-1 count: 95
中间省略...
Thread-1 count: 12
Thread-2 count: 7
Thread-0 count: 9
Thread-2 count: 5
Thread-1 count: 6
Thread-2 count: 3
Thread-0 count: 4
Thread-2 count: 1
Thread-1 count: 2
2. 数组类型的使用
public class AtomicIntegerArrayTest {
private final static AtomicIntegerArray ATOMIC_INTEGER_ARRAY = new AtomicIntegerArray(new int[]{1,2,3,4,5,6,7,8,9,10});
public static void main(String []args) throws InterruptedException {
Thread []threads = new Thread[10];
for(int i = 0 ; i < 10 ; i++) {
final int index = i;
threads[i] = new Thread() {
public void run() {
int original = ATOMIC_INTEGER_ARRAY.get(index);
int result = ATOMIC_INTEGER_ARRAY.addAndGet(index, index + 1);
System.out.println("currentThread：" + Thread.currentThread().getName() + " , 原始值为：" + original + "，增加后的结果为：" + result);
}
};
threads[i].start();
}
for(Thread thread : threads) {
thread.join();
}
System.out.println("=========================>\n执行已经完成，结果列表：");
for(int i = 0 ; i < ATOMIC_INTEGER_ARRAY.length() ; i++) {
System.out.println(ATOMIC_INTEGER_ARRAY.get(i));
}
}
}
currentThread：Thread-0 , 原始值为：1，增加后的结果为：2
currentThread：Thread-3 , 原始值为：4，增加后的结果为：8
currentThread：Thread-2 , 原始值为：3，增加后的结果为：6
currentThread：Thread-1 , 原始值为：2，增加后的结果为：4
currentThread：Thread-5 , 原始值为：6，增加后的结果为：12
currentThread：Thread-4 , 原始值为：5，增加后的结果为：10
currentThread：Thread-6 , 原始值为：7，增加后的结果为：14
currentThread：Thread-7 , 原始值为：8，增加后的结果为：16
currentThread：Thread-8 , 原始值为：9，增加后的结果为：18
currentThread：Thread-9 , 原始值为：10，增加后的结果为：20
=========================>
执行已经完成，结果列表：
2
4
6
8
10
12
14
16
18
20
3. 引用类型的使用
public class AtomicReferenceTest {
public static void main(String[] args) {
People people1 =new People("Bom", 0);
People people2 =new People("Tom",10);
//先初始化一个值，如果不初始化则默认值为null
AtomicReference<People> reference = new AtomicReference<>(people1);
People people3 = reference.get();
if (people3.equals(people1)) {
System.out.println("people3:" + people3);
} else {
System.out.println("else:" + people3);
}
boolean b = reference.compareAndSet(null, people2);
System.out.println("myClass.main-"+b+"--"+reference.get());
boolean b1 = reference.compareAndSet(people1, people2);
System.out.println("myClass.main-"+b1+"--"+reference.get());
new Thread(new Runnable() {
@Override
public void run() {
System.out.println(Thread.currentThread().getName());
People people = reference.get();
people.setName("Tom"+Thread.currentThread().getName());
people.setAge(people.getAge()+1);
reference.getAndSet(people);
System.out.println(Thread.currentThread().getName()+reference.get().toString());
}
}).start();
new Thread(new Runnable() {
@Override
public void run() {
System.out.println(Thread.currentThread().getName());
People people = reference.get();
people.setName("Tom"+Thread.currentThread().getName());
people.setAge(people.getAge()+4);
reference.getAndSet(people);
System.out.println(Thread.currentThread().getName()+reference.get().toString());
}
}).start();
}
}
class People {
private String name;
private int age;
public People(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "People{" +
"name='" + name + ''' +
", age=" + age +
'}';
}
}
4.字段类型的使用
public class AtomicIntegerFieldUpdaterTest {
public final static AtomicIntegerFieldUpdater<A> ATOMIC_INTEGER_UPDATER = AtomicIntegerFieldUpdater.newUpdater(A.class, "intValue");
public static void main(String[] args) {
final A a = new A();
for (int i = 0; i < 10; i++) {
new Thread() {
public void run() {
System.out.println(
Thread.currentThread().getName() + " " + ATOMIC_INTEGER_UPDATER.get(a));
ATOMIC_INTEGER_UPDATER.addAndGet(a, 11);
System.out.println(
Thread.currentThread().getName() + " " + ATOMIC_INTEGER_UPDATER.get(a));
if (ATOMIC_INTEGER_UPDATER.compareAndSet(a, ATOMIC_INTEGER_UPDATER.get(a), 120)) {
System.out.println(Thread.currentThread().getName() + " 对应的值做了修改！");
}
System.out.println(
Thread.currentThread().getName() + " " + ATOMIC_INTEGER_UPDATER.get(a));
}
}.start();
}
}
static class A {
volatile int intValue = 100;
}
}
Thread-0 100
Thread-2 100
Thread-1 100
Thread-2 122
Thread-3 111
Thread-5 120
Thread-0 111
Thread-5 142
Thread-3 131
Thread-2 对应的值做了修改！
Thread-2 120
Thread-8 120
Thread-4 133
Thread-1 133
Thread-9 142
Thread-4 142
Thread-4 对应的值做了修改！
Thread-8 131
Thread-3 对应的值做了修改！
Thread-3 120
Thread-7 120
Thread-7 131
Thread-5 对应的值做了修改！
Thread-5 120
Thread-6 120
Thread-0 对应的值做了修改！
Thread-6 131
Thread-7 对应的值做了修改！
Thread-8 对应的值做了修改！
Thread-4 120
Thread-9 131
Thread-1 对应的值做了修改！
Thread-9 对应的值做了修改！
Thread-8 120
Thread-7 120
Thread-6 对应的值做了修改！
Thread-0 131
Thread-6 120
Thread-9 120
Thread-1 120
到此这篇关于Java多线程 原子性操作类的使用的文章就介绍到这了,更多相关Java多线程 原子性操作类内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
