案例介绍

  • A 线程打印 5 次 A，B 线程打印 10 次 B，C 线程打印 15 次 C,按照 此顺序循环 10 轮

    1. public class ThreadDemo2 {
    3.   private ReentrantLock reentrantLock = new ReentrantLock();
    5.   private Condition c1 = reentrantLock.newCondition();
    7.   private Condition c2 = reentrantLock.newCondition();
    9.   private Condition c3 = reentrantLock.newCondition();
    11.   private int flag = 1;
    13.   private void printA() {
    14.       reentrantLock.lock();
    15.       try {
    16.           while (flag != 1) {
    17.               c1.await();
    18.           }
    19.           for (int i = 0; i < 5; i++) {
    20.               System.out.print("A ");
    21.           }
    22.           System.out.println();
    23.           flag = 2;
    24.           c2.signal();
    25.       } catch (Exception e) {
    26.           e.printStackTrace();
    27.       } finally {
    28.           reentrantLock.unlock();
    29.       }
    30.   }
    32.   private void printB() {
    33.       reentrantLock.lock();
    34.       try {
    35.           while (flag != 2) {
    36.               c2.await();
    37.           }
    38.           for (int i = 0; i < 10; i++) {
    39.               System.out.print("B ");
    40.           }
    41.           System.out.println();
    42.           flag = 3;
    43.           c3.signal();
    44.       } catch (Exception e) {
    45.           e.printStackTrace();
    46.       } finally {
    47.           reentrantLock.unlock();
    48.       }
    49.   }
    51.   private void printC() {
    52.       reentrantLock.lock();
    53.       try {
    54.           while (flag != 3) {
    55.               c3.await();
    56.           }
    57.           for (int i = 0; i < 15; i++) {
    58.               System.out.print("C ");
    59.           }
    60.           System.out.println();
    61.           flag = 1;
    62.           c1.signal();
    63.       } catch (Exception e) {
    64.           e.printStackTrace();
    65.       } finally {
    66.           reentrantLock.unlock();
    67.       }
    68.   }
    70.   public static void main(String[] args) {
    71.       ThreadDemo2 demo2 = new ThreadDemo2();
    73.       new Thread(() -> {
    74.           for (int i = 0; i < 3; i++) {
    75.               demo2.printA();
    76.           }
    77.       }).start();
    79.       new Thread(() -> {
    80.           for (int i = 0; i < 3; i++) {
    81.               demo2.printB();
    82.           }
    83.       }).start();
    85.       new Thread(() -> {
    86.           for (int i = 0; i < 3; i++) {
    87.               demo2.printC();
    88.           }
    89.       }).start();
    90.   }
    91. }

  • image.png