使用synchronized
package com.pb.thread.demo5;/**使用synchronized * 一个线程加一运算，一个线程做减法运算，多个线程同时交替运行 * * @author Denny * */public class Count { private int num = 0; private boolean flag = false; // 标识 //加法 public synchronized void add() { while (flag) { try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } this.num++; //加 System.out.println(Thread.currentThread().getName() + "........" + this.num); this.flag=true; //设置标识为true notifyAll(); //唤醒所有在线程池中冻结的线程，会把所有都唤醒 } //减法 public synchronized void sub() { while (!flag) { try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } this.num--; //减 System.out.println(Thread.currentThread().getName() + "........" + this.num); this.flag=false; //设置标识为true notifyAll(); //唤醒所有在线程池中冻结的线程，会把所有都唤醒 }}
package com.pb.thread.demo5;public class Add implements Runnable { private Count count; public Add(Count count){ this.count=count; } @Override public void run() { while(true){ count.add(); } }}//================package com.pb.thread.demo5;public class Sub implements Runnable { private Count count; public Sub(Count count){ this.count=count; } @Override public void run() { while(true){ count.sub(); } }}
测试类
package com.pb.thread.demo5;public class CountTest { public static void main(String[] args) { Count c=new Count(); Add add=new Add(c); Sub sub=new Sub(c); Thread t1=new Thread(add); Thread t2=new Thread(add); Thread t3=new Thread(sub); Thread t4=new Thread(sub); t1.start(); t2.start(); t3.start(); t4.start(); }}
结果：
Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0
不使用synchronized
package com.pb.thread.demo4;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * 一个线程加一运算，一个线程做减法运算，多个线程同时交替运行 * @author Denny * */public class Count { private int num = 0; private boolean flag=false; // 标识 Lock lock = new ReentrantLock(); // 锁 Condition add = lock.newCondition(); // 加法锁 Condition sub = lock.newCondition();// 减法锁 public void add() { lock.lock();// 锁上 try { while (flag) { //循环判断 add.await(); } this.num++; System.out.println(Thread.currentThread().getName() + "........" + this.num); this.flag = true; // 设置标识 sub.signal(); // 唤醒指定线程 } catch (InterruptedException e) { e.printStackTrace(); }finally{ lock.unlock(); } } public void sub() { lock.lock();// 锁上 try { while (!flag) {//循环判断 sub.await(); } this.num--; System.out.println(Thread.currentThread().getName() + "........" + this.num); this.flag = false; // 设置标识 add.signal(); // 唤醒指定线程 } catch (InterruptedException e) { e.printStackTrace(); }finally{ lock.unlock(); } }}
package com.pb.thread.demo4;public class Add implements Runnable { private Count count; public Add(Count count){ this.count=count; } @Override public void run() { while(true){ count.add(); } }}
package com.pb.thread.demo4;public class Sub implements Runnable { private Count count; public Sub(Count count){ this.count=count; } @Override public void run() { while(true){ count.sub(); } }}
package com.pb.thread.demo4;public class CountTest { public static void main(String[] args) { Count c=new Count(); Add add=new Add(c); Sub sub=new Sub(c); Thread t1=new Thread(add); Thread t2=new Thread(add); Thread t3=new Thread(sub); Thread t4=new Thread(sub); t1.start(); t2.start(); t3.start(); t4.start(); }}
结果：
Thread-1........1Thread-3........0Thread-0........1Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0