多線程案例

1、生產者消費者案例

1.使用synchronized關鍵字實現

 1 public class TestProductorAndConsumer {  2         public static void main(String[] args) {  3             Clerk clerk = new Clerk();  4             Productor pro = new Productor(clerk);  5             Consumer cus = new Consumer(clerk);  6         
 7             new Thread(pro, "生產者 A").start();  8             new Thread(cus, "消費者 B").start();  9             new Thread(pro, "生產者 C").start(); 10             new Thread(cus, "消費者 D").start(); 11  } 12 } 13 //店員
14 class Clerk{ 15     private int product = 0; 16     //進貨
17     public synchronized void get(){    //循環次數：0
18         while(product >= 1){ 19             System.out.println("產品已滿！"); 20             try { 21                 this.wait();    //爲了不虛假喚醒問題，wait應該老是使用在循環中
22             } catch (InterruptedException e) { 23  } 24  } 25         System.out.println(Thread.currentThread().getName() + " : " + ++product); 26         this.notifyAll(); 27  } 28     //賣貨
29     public synchronized void sale(){    //product = 0; 循環次數：0
30         while(product <= 0){ 31             System.out.println("缺貨！"); 32             try { 33                 this.wait(); 34             } catch (InterruptedException e) { 35  } 36  } 37         System.out.println(Thread.currentThread().getName() + " : " + --product); 38         this.notifyAll(); 39  } 40 } 41 //生產者
42 class Productor implements Runnable{ 43     private Clerk clerk; 44     public Productor(Clerk clerk) { 45         this.clerk = clerk; 46  } 47     public void run() { 48         for (int i = 0; i < 20; i++) { 49             try { 50                 Thread.sleep(200); 51             } catch (InterruptedException e) { 52  } 53  clerk.get(); 54  } 55  } 56 } 57 //消費者
58 class Consumer implements Runnable{ 59     private Clerk clerk; 60     public Consumer(Clerk clerk) { 61         this.clerk = clerk; 62  } 63     public void run() { 64         for (int i = 0; i < 20; i++) { 65  clerk.sale(); 66  } 67  } 68 }

2.使用Lock同步鎖和Condition類實現

 1 public class TestProductorAndConsumerForLock {  2     public static void main(String[] args) {  3         Clerk clerk = new Clerk();  4         Productor pro = new Productor(clerk);  5         Consumer con = new Consumer(clerk);  6 
 7         new Thread(pro, "生產者 A").start();  8         new Thread(con, "消費者 B").start();  9 // new Thread(pro, "生產者 C").start(); 10 // new Thread(con, "消費者 D").start();
11  } 12 } 13 class Clerk { 14     private int product = 0; 15     private Lock lock = new ReentrantLock(); 16     private Condition condition = lock.newCondition(); 17     // 進貨
18     public void get() { 19  lock.lock(); 20         try { 21             if (product >= 1) { // 爲了不虛假喚醒，應該老是使用在循環中。
22                 System.out.println("產品已滿！"); 23                 try { 24  condition.await(); 25                 } catch (InterruptedException e) { 26  } 27  } 28             System.out.println(Thread.currentThread().getName() + " : "+ ++product); 29  condition.signalAll(); 30         } finally { 31  lock.unlock(); 32  } 33  } 34     // 賣貨
35     public void sale() { 36  lock.lock(); 37         try { 38             if (product <= 0) { 39                 System.out.println("缺貨！"); 40                 try { 41  condition.await(); 42                 } catch (InterruptedException e) { 43  } 44  } 45             System.out.println(Thread.currentThread().getName() + " : "+ --product); 46  condition.signalAll(); 47         } finally { 48  lock.unlock(); 49  } 50  } 51 } 52 
53 // 生產者
54 class Productor implements Runnable { 55     private Clerk clerk; 56     public Productor(Clerk clerk) { 57         this.clerk = clerk; 58  } 59     public void run() { 60         for (int i = 0; i < 20; i++) { 61             try { 62                 Thread.sleep(200); 63             } catch (InterruptedException e) { 64  e.printStackTrace(); 65  } 66  clerk.get(); 67  } 68  } 69 } 70 
71 // 消費者
72 class Consumer implements Runnable { 73     private Clerk clerk; 74     public Consumer(Clerk clerk) { 75         this.clerk = clerk; 76  } 77     public void run() { 78         for (int i = 0; i < 20; i++) { 79  clerk.sale(); 80  } 81  } 82 }

 

2、線程按序交替

　　編寫一個程序，開啓3個線程，這三個線程的ID分別爲A、B、C，每一個線程將本身的ID在屏幕上打印10遍，要求輸出的結果必須按順序顯示。如：ABCABC......依次遞歸。

 1 public class TestABCAlternate {  2     public static void main(String[] args) {  3         AlternateDemo ad = new AlternateDemo();  4         new Thread(new Runnable() {  5             public void run() {  6                 for (int i = 1; i <= 10; i++) {  7  ad.loopA(i);  8  }  9  } 10         }, "A").start(); 11         new Thread(new Runnable() { 12             public void run() { 13                 for (int i = 1; i <= 10; i++) { 14  ad.loopB(i); 15  } 16  } 17         }, "B").start(); 18         new Thread(new Runnable() { 19             public void run() { 20                 for (int i = 1; i <= 10; i++) { 21  ad.loopC(i); 22                     System.out.println("-----------------------------------"); 23  } 24  } 25         }, "C").start(); 26  } 27 } 28 
29 class AlternateDemo{ 30     private int number = 1; //當前正在執行線程的標記
31     private Lock lock = new ReentrantLock(); 32     private Condition condition1 = lock.newCondition(); 33     private Condition condition2 = lock.newCondition(); 34     private Condition condition3 = lock.newCondition(); 35     
36     public void loopA(int totalLoop){    //totalLoop : 循環第幾輪
37  lock.lock(); 38         try { 39             if(number != 1){    //1. 判斷
40  condition1.await(); 41  } 42             //2. 打印
43             for (int i = 1; i <= 1; i++) { 44                 System.out.println(Thread.currentThread().getName() + "\t" + i + "\t" + totalLoop); 45  } 46             //3. 喚醒
47             number = 2; 48  condition2.signal(); 49         } catch (Exception e) { 50  e.printStackTrace(); 51         } finally { 52  lock.unlock(); 53  } 54  } 55     public void loopB(int totalLoop){ 56  lock.lock(); 57         try { 58             if(number != 2){    //1. 判斷
59  condition2.await(); 60  } 61             //2. 打印
62             for (int i = 1; i <= 1; i++) { 63                 System.out.println(Thread.currentThread().getName() + "\t" + i + "\t" + totalLoop); 64  } 65             //3. 喚醒
66             number = 3; 67  condition3.signal(); 68         } catch (Exception e) { 69  e.printStackTrace(); 70         } finally { 71  lock.unlock(); 72  } 73  } 74     public void loopC(int totalLoop){ 75  lock.lock(); 76         try { 77             if(number != 3){    //1. 判斷
78  condition3.await(); 79  } 80             //2. 打印
81             for (int i = 1; i <= 1; i++) { 82                 System.out.println(Thread.currentThread().getName() + "\t" + i + "\t" + totalLoop); 83  } 84             //3. 喚醒
85             number = 1; 86  condition1.signal(); 87         } catch (Exception e) { 88  e.printStackTrace(); 89         } finally { 90  lock.unlock(); 91  } 92  } 93 }