有两个子线程(线程2,线程3)和主线程,实现以下操作:
线程2先执行10次,然后 线程3执行20次,再由主线程执行30次,然后再让线程2执行10次,再让线程3执行20次…依次类推,执行10次。
程序如下:
package test; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantLock; import java.util.concurrent.locks.ReentrantReadWriteLock; public class ConditionTest { public static void main(String[] args) { final Bussiness bussiness = new Bussiness(); new Thread(new Runnable() { @Override public void run() { for(int i=0;i<10;i++){ bussiness.sub2(i); } } }).start(); new Thread(new Runnable() { @Override public void run() { for(int i=0;i<10;i++){ bussiness.sub3(i); } } }).start(); for(int i=0;i<10;i++){ bussiness.sub1(i); } } } class Bussiness{ Lock lock=new ReentrantLock(); /* 此处使用了三个Condition , 原因:如果只使用一个Condition时,假如 线程 1 和 线程 2 都处于 await状态 的时候, 线程 3在signal()时 会随机唤醒 线程1,线程2中的一个,达不到顺序执行的要求*/ Condition condition1=lock.newCondition(); Condition condition2=lock.newCondition(); Condition condition3=lock.newCondition(); private int num=2;//用于表示正在执行的线程编码 public void sub2(int i){ lock.lock(); try{ while(num != 2){ try{ condition2.await(); }catch(Exception e){ e.printStackTrace(); } } for(int j=0;j<10;j++){ System.out.println("sub2 thread sequence of "+j+" loop of "+i); } num=3; condition3.signal(); }finally{ lock.unlock(); } } public void sub3(int i){ lock.lock(); try{ while(num != 3){ try{ condition3.await(); }catch(Exception e){ e.printStackTrace(); } } for(int j=0;j<20;j++){ System.out.println("sub3 thread sequence of "+j+" loop of "+i); } num=1; condition1.signal(); }finally { lock.unlock(); } } public void sub1(int i){ lock.lock(); try{ while(num != 1){ try { condition1.await(); } catch (InterruptedException e) { e.printStackTrace(); } } for(int j=0;j<30;j++){ System.out.println("sub1 thread sequence of "+j+" loop of "+i); } num=2; condition2.signal(); }finally{ lock.unlock(); } } }
结果如下:
sub2 thread sequence of 0 loop of 0
sub2 thread sequence of 1 loop of 0
sub2 thread sequence of 2 loop of 0
sub2 thread sequence of 3 loop of 0
sub2 thread sequence of 4 loop of 0
sub2 thread sequence of 5 loop of 0
sub2 thread sequence of 6 loop of 0
sub2 thread sequence of 7 loop of 0
sub2 thread sequence of 8 loop of 0
sub2 thread sequence of 9 loop of 0
sub3 thread sequence of 0 loop of 0
sub3 thread sequence of 1 loop of 0
sub3 thread sequence of 2 loop of 0
sub3 thread sequence of 3 loop of 0
sub3 thread sequence of 4 loop of 0
sub3 thread sequence of 5 loop of 0
sub3 thread sequence of 6 loop of 0
sub3 thread sequence of 7 loop of 0
sub3 thread sequence of 8 loop of 0
sub3 thread sequence of 9 loop of 0
sub3 thread sequence of 10 loop of 0
sub3 thread sequence of 11 loop of 0
sub3 thread sequence of 12 loop of 0
sub3 thread sequence of 13 loop of 0
sub3 thread sequence of 14 loop of 0
sub3 thread sequence of 15 loop of 0
sub3 thread sequence of 16 loop of 0
sub3 thread sequence of 17 loop of 0
sub3 thread sequence of 18 loop of 0
sub3 thread sequence of 19 loop of 0
sub1 thread sequence of 0 loop of 0
sub1 thread sequence of 1 loop of 0
sub1 thread sequence of 2 loop of 0
sub1 thread sequence of 3 loop of 0
sub1 thread sequence of 4 loop of 0
sub1 thread sequence of 5 loop of 0
sub1 thread sequence of 6 loop of 0
sub1 thread sequence of 7 loop of 0
……
太多了,复制了一部分。