java AtomicInteger

来源：互联网发布：设计模式php 编辑：程序博客网时间：2024/05/01 05:53

AtomicInteger，一个提供原子操作的Integer的类。在Java语言中，++i和i++操作并不是线程安全的，在使用的时候，不可避免的会用到synchronized关键字。而AtomicInteger则通过一种线程安全的加减操作接口。

import java.text.SimpleDateFormat;

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
* @Description
* @Author
* @Date 2015-5-8 上午9:37:45
*/
public class ConcurrentAtomicTest {

private final static AtomicInteger atomicInteger=new AtomicInteger(1);
private static volatile int integer=1;;

/**
* @Description TODO
* @Return void
* @Throws
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// testAtomicInteger();
testInteger2();

}

public static void testAtomicInteger() {
String time = new SimpleDateFormat("HH:mm:ss").format(new Date());
System.out.println("Start time : " + time);

int temp=atomicInteger.addAndGet(1);//add
atomicInteger.get();//get current
System.out.print(temp+",");

temp=atomicInteger.decrementAndGet();//Atomically decrements by one the current value.
System.out.print(temp+",");

temp=atomicInteger.getAndIncrement();//Atomically decrements by one the current value.
System.out.print(temp+",");

temp=atomicInteger.intValue();//Atomically decrements by one the current value.
System.out.print(temp+",");

atomicInteger.set(0);//Atomically decrements by one the current value.
temp=atomicInteger.get();
System.out.println(temp+",");

//result:2,1,1,2,0,

ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(5); // 创建5个执行线程

Runnable runnable = new Runnable() {
@Override
public void run() {
String time = new SimpleDateFormat("HH:mm:ss").format(new Date());
atomicInteger.incrementAndGet();
System.out.println("Now Time : " + time+",integer:"+integer);
}
};

executor.scheduleWithFixedDelay(runnable, 2, 3, TimeUnit.SECONDS);
}

/**
* 测试int加1
* @Description TODO
* @Return void
* @Throws
*/
public static void testInteger2() {
String time = new SimpleDateFormat("HH:mm:ss").format(new Date());
System.out.println("Start time : " + time);

integer++;
System.out.println("integer ++:"+integer);

integer--;
System.out.println("integer --:"+integer);

ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(5); // 创建5个执行线程

Runnable runnable = new Runnable() {
@Override
public void run() {
String time = new SimpleDateFormat("HH:mm:ss").format(new Date());
integer=integer+1;
System.out.println("Now Time : " + time+",testInteger2 Integer:"+atomicInteger.get());
}
};

executor.scheduleWithFixedDelay(runnable, 2, 3, TimeUnit.SECONDS);
}
// Start time : 10:27:16
// integer ++:2
// integer --:1
// Now Time : 10:27:18,testInteger2 Integer:1
// Now Time : 10:27:21,testInteger2 Integer:1
// Now Time : 10:27:24,testInteger2 Integer:1
// Now Time : 10:27:27,testInteger2 Integer:1

}

1 0