Java线程并不是并行工作的

时间:2016-12-23 05:37:16

标签: java multithreading concurrency

以下是我的代码。我期待t1和t2应该并行运行但是在完成t1之后,t2开始了。我做错了什么。实际上我正试图复制生产者和消费者的问题,但是我正在制造一些混乱的地方。

import java.util.ArrayList;
import java.util.List;

public class BankThread {

    static List<String> amount = new ArrayList<String>();
    public static void main(String[] args) {
        Deposit dep = new Deposit();
        WithDraw wDraw = new WithDraw();
        Thread t1 = new Thread(dep);
        Thread t2 = new Thread(wDraw);
        t1.start();
        t2.start();

    }

}

class Deposit extends BankThread implements Runnable {

    public void run(){
        for (int i = 1; i < 10; i++) {
            amount.add(""+(i*100));
            System.out.println("Deposit #" + i
            + " put: " + i);
            try {
            Thread.sleep((int)(1000));
            } catch (InterruptedException e) { }
            }

    }
}

class WithDraw extends BankThread implements Runnable{

    public void run(){
        System.out.println("In withdraw"+amount.size());
        try {
            for (int i = 0; i< amount.size(); i++) {
            System.out.println("Withdraw #" + amount.get(i)
                    + " removed " + amount.remove(i));
            Thread.sleep((int)(1000));
            }} catch (InterruptedException e) { }
        }

    }

1 个答案:

答案 0 :(得分:1)

当我运行它时,输出是:

Deposit #1 put: 1
In withdraw1
Withdraw #100 removed 100
Deposit #2 put: 2
Deposit #3 put: 3
Deposit #4 put: 4
Deposit #5 put: 5
Deposit #6 put: 6
Deposit #7 put: 7
Deposit #8 put: 8
Deposit #9 put: 9

所以他们确实并行运行。问题是撤销只通过循环一次,这可能不是我想要的。

原因是它在for循环开始时查看一次的大小,因此它看不到新项目。