【Java】线程安全之原子性Atomic(AtomicInteger|LongAdder|AtomicLong)

Z时代
2024-01-10
分类：技术分享

线程安全性

原子性

Atomic包

案例

package com.keytech.task;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.LongAdder;
/**
* @className: AtomicTest
* @description: TODO 类描述
* @author: mac
* @date: 2020/12/27
**/
public class AtomicTest {
private static Integer clientTotal=5000;
private static Integer threadTotal=200;
private static AtomicInteger count=new AtomicInteger(0);
public static void main(String[] args) {
ExecutorService executorService = Executors.newCachedThreadPool();
Semaphore semaphore= new Semaphore(threadTotal);
for (int i = 0; i <clientTotal ; i++) {
executorService.execute(()->{
try{
semaphore.acquire();
update();
semaphore.release();
}catch (Exception e){
e.printStackTrace();
}
});
}
executorService.shutdown();
System.out.println("count:"+count);
}
private static void update(){
count.incrementAndGet();
}
}

getAndAddInt源码

public final int getAndAddInt(Object var1, long var2, int var4) {
int var5;
do {
var5 = this.getIntVolatile(var1, var2);
} while(!this.compareAndSwapInt(var1, var2, var5, var5 + var4));
return var5;}

LongAddr

package com.keytech.task;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.LongAdder;
/**
* @className: LongAddrTest
* @description: TODO 类描述
* @author: mac
* @date: 2020/12/28
**/
public class LongAddrTest {
private static Integer clientTotal=5000;
private static Integer threadTotal=200;
private static LongAdder count=new LongAdder();
public static void main(String[] args) {
ExecutorService executorService = Executors.newCachedThreadPool();
Semaphore semaphore=new Semaphore(threadTotal);
for (int i = 0; i < clientTotal; i++) {
try{
semaphore.acquire();
update();
semaphore.release();
}catch (Exception e){
e.printStackTrace();
}
}
executorService.shutdown();
System.out.println("count"+count);
}
private static void update(){
count.increment();
}
}

AtomicLong

package com.keytech.task;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicLong;
/**
* @className: AtomicLongTest
* @description: TODO 类描述
* @author: mac
* @date: 2020/12/28
**/
public class AtomicLongTest {
private static Integer clientTotal=5000;
private static Integer threadTotal=200;
private static AtomicLong count=new AtomicLong();
public static void main(String[] args) {
ExecutorService executorService = Executors.newCachedThreadPool();
Semaphore semaphore=new Semaphore(threadTotal);
for (int i = 0; i < clientTotal; i++) {
try{
semaphore.tryAcquire();
update();
semaphore.release();
}catch (Exception e){
e.printStackTrace();
}
}
executorService.shutdown();
System.out.println("count"+count);
}
private static void update(){
count.incrementAndGet();
}
}