java - 链接的阻塞队列中的值未正确传递

Question

这是如何工作的，我的 jar 将进入传送带，然后使用 sanitizer 类进行扫描，但我遇到了问题，因为我的 jar 没有正确通过，这意味着我的一些 jar 没有被扫描，例如:扫描 jar 1后，提示 jar 2已添加到皮带中，但直接跳到 jar 3

public class AsiaPacificFruitFactory {


public static void main(String[] args) {
    LinkedBlockingQueue<Can>beltQ = new LinkedBlockingQueue<Can>();
    LinkedBlockingQueue<Can>sterilizeQ = new LinkedBlockingQueue<Can>();

    Belt b = new Belt(beltQ);
    Sterilize s = new Sterilize(beltQ, sterilizeQ);
    b.start();
    s.start();
}

}

   class Belt extends Thread{
        LinkedBlockingQueue<Can>beltQ;

    public Belt (LinkedBlockingQueue<Can> beltQ){
        this.beltQ = beltQ;
    }
    @Override
    public void run(){
        while(true){
            addCan();
            try{
                Thread.sleep(500);
            }catch (Exception e){}
        }
    }

    public void addCan(){
        for (int i=1; i<501; i++){
            try{
                beltQ.put(new Can(i));
                System.out.println("Can " + i + " has been added into the belt" );
                Thread.sleep(500);
            }catch (Exception e){}
        }
    }
}

class Scanner implements Callable<Can>{  
    Can c;

    public Scanner (Can c){
        this.c = c;
    }

    Random rand = new Random();

    public Can call() throws Exception{
        System.out.println("Scanning can " + c.CanNo + " for dents");
        c.getDefect();

        if(c.defect == 3){
            System.out.println("Can " + c.CanNo + " is dented");
            return null;
        }
        else{
            System.out.println("Can " + c.CanNo + " is not dented");
            return c;
        }
    }
}

class Sterilize extends Thread{
    LinkedBlockingQueue<Can>beltQ;
    LinkedBlockingQueue<Can>sterilizeQ;

    public Sterilize (LinkedBlockingQueue<Can> beltQ, LinkedBlockingQueue<Can>sterilizeQ){
        this.beltQ = beltQ;
        this.sterilizeQ = sterilizeQ;
    }


    public void run(){
        while(true){
            try{
                Can c = beltQ.take();
                ExecutorService exe = Executors.newCachedThreadPool();
                Future<Can> tempCan = exe.submit(new Scanner(c));
                if(tempCan.get() == null){
                    System.out.println("Can " + c.CanNo + " has not passed the scanning section");
                    continue;
                }else{
                    sterilizeQ.put(beltQ.take());
                }
            exe.shutdown();
            }catch(Exception e){}
        }
    }
}

我的输出是这样的:

Can 1 has been added into the belt
Scanning can 1 for dents
Can 1 is not dented
Can 2 has been added into the belt
         Can 1 has passed scanning......proceeding with sterilizing now
Can 3 has been added into the belt
Scanning can 3 for dents
Can 3 is not dented
Can 4 has been added into the belt
         Can 3 has passed scanning......proceeding with sterilizing now

Answer 1

问题出在 Sterilize run 方法

替换

sterilizeQ.put(beltQ.take());

与

sterilizeQ.put(c);