【java并发练习】用6个线程求和（保证每个线程求和次数之差最大不超过1）

分析

需要共享一些变量&＃xff0c;当前的求和位置&＃xff0c;目前的累计和&＃xff0c;和完成求和的线程个数
每个线程有一个自己的编号&＃xff0c;当flag % 6 &＃61;&＃61; index就可以进行一次求和&＃xff0c;并输出信息&＃xff0c;否则则skip
这样保证了他们每个线程求和数都是几乎一样的
最后main线程需要等待所有的thread退出&＃xff0c;通过exitNum来判断是否满足6个&＃xff0c;最后退出前输出求和信息

code

package calculate;public class getSum {public static void main(String []args) {Share share &＃61; new Share();// 6 threadsTestThread t1 &＃61; new TestThread(share, 0);TestThread t2 &＃61; new TestThread(share, 1);TestThread t3 &＃61; new TestThread(share, 2);TestThread t4 &＃61; new TestThread(share, 3);TestThread t5 &＃61; new TestThread(share, 4);TestThread t6 &＃61; new TestThread(share, 5);t1.start();t2.start();t3.start();t4.start(); t5.start();t6.start();// when all threads exitwhile(share.exitNum !&＃61; 6) {try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();break;}}System.out.println("最终的结果是" &＃43; Long.toString(share.sum));}}class Share {public volatile int flag &＃61; 0;public volatile long sum &＃61; 0;public volatile int exitNum &＃61; 0;
}class TestThread extends Thread {// 引入仓库private Share share;// 引入标志private int index;public TestThread(Share share, int index) {this.share &＃61; share;this.index &＃61; index;}public void run() {// 共享变量类里面有flag和sumwhile (share.flag <&＃61; 1000) {if(share.flag % 6 &＃61;&＃61; index) {share.sum &＃43;&＃61; share.flag;System.out.println("thread" &＃43; index &＃43; " is adding" &＃43; share.flag);share.flag &＃43;&＃61; 1;}}share.exitNum &＃43;&＃61; 1;System.out.println("thread" &＃43; index &＃43; " is exiting");}
}


结果

总结

通过一个共享变量类来完成变量共享
通过共享变量来协调thread之间的关系