009.多线程-AtomicInteger

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package cn.qbz.thread;

import java.util.concurrent.atomic.AtomicInteger;

public class AtomicTest {
    public static void main(String[] args) {
        AtomicInteger count = new AtomicInteger(0);
        //分10个线程，每个线程自增2000次
        for (int i = 0; i < 10; i++) {
            new Thread(new ThreadTest1(count)).start();
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(count.get());

    }
}

class ThreadTest1 implements Runnable {
    private AtomicInteger integer;

    ThreadTest1(AtomicInteger integer) {
        this.integer = integer;
    }

    public void run() {
        for (int i = 0; i < 2000; i++) {
            integer.incrementAndGet();
        }
    }
}

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此时的数值会小于20000

package cn.qbz.thread;


public class AtomicTest {
	//静态变量可为多线程共享
    private static Integer count = 0;

    public static void main(String[] args) {
        //分10个线程，每个线程自增2000次
        for (int i = 0; i < 10; i++) {
            new Thread(new Runnable() {
                public void run() {
                    for (int i = 0; i < 2000; i++) {
                        count++;
                    }
                }
            }).start();
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(count);

    }
}

---

如上面一样，使用AtomicInteger

package cn.qbz.thread;


import java.util.concurrent.atomic.AtomicInteger;

public class AtomicTest {

    public static void main(String[] args) {
        final AtomicInteger count = new AtomicInteger(0);
        //分10个线程，每个线程自增2000次
        for (int i = 0; i < 10; i++) {
            new Thread(new Runnable() {
                public void run() {
                    for (int i = 0; i < 2000; i++) {
                        count.incrementAndGet();
                    }
                }
            }).start();
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(count.get());

    }
}

---

其他的Atomic类与此类似