1 package multithread4;

 2

 3 /*

 4  * 生产者，消费者。

 5  *

 6  * 多生产者，多消费者的问题。

 7  *

 8  * if判断标记，只有一次，会导致不该运行的线程运行了。出现了数据错误的情况。

 9  * while判断标记，解决了线程获取执行权后，是否要运行！

10  *

11  * notify：只能唤醒一个线程，如果本方唤醒了本方，没有意义。而且while判断标记+notify会产生死锁

12  * notifyAll解决了，本方线程一定会唤醒对方线程

13  *

14  * 死锁 四个线程都等待没有被唤醒也是一种情况，悬挂

15  */

16

17 class Resource2{

18     private String name;

19     private int count = 1;

20     private boolean flag = false;

21     public synchronized void set(String name) {

22

23 /*if*/ while (flag) {

24             try {

25                 this.wait();

26             } catch (InterruptedException e) {

27

28             }

29         }

30         this.name = name + count;

31         count++;

32         System.out.println(Thread.currentThread().getName()+"..生产者.."+this.name);

33         flag = true;

34 //        notify();

35         notifyAll();

36     }

37     public synchronized void out() {

38 /*if*/ while (!flag) {

39             try {

40                 this.wait();

41             } catch (InterruptedException e) {

42

43             }

44         }

45         System.out.println(Thread.currentThread().getName()+"..消费者......"+this.name);

46         flag = false;

47 //        notify();

48         notifyAll();//为了解决死锁 将其余三个都唤醒

49     }

50 }

51

52 class Producer implements Runnable{

53     private Resource2 r;

54     public Producer(Resource2 r) {

55         this.r = r;

56     }

57     public void run() {

58         while(true) {

59             r.set("烤鸭");

60         }

61     }

62 }

63 class Consumer implements Runnable{

64     private Resource2 r;

65     public Consumer(Resource2 r) {

66         this.r = r;

67     }

68     public void run() {

69         while(true) {

70             r.out();

71         }

72     }

73 }

74 public class ProducerConsumerDemo {

75

76     public static void main(String[] args) {

77

78         Resource2 r = new Resource2();

79         Producer pro = new Producer(r);

80         Consumer con = new Consumer(r);

81

82         Thread t0 = new Thread(pro);

83         Thread t1 = new Thread(pro);

84         Thread t2 = new Thread(con);

85         Thread t3 = new Thread(con);

86

87         t0.start();

88         t1.start();

89         t2.start();

90         t3.start();

91     }

92

93 }