一个线程加一运算，一个线程做减一运算，多个线程同时交替运行--synchronized...

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truenotifyAll(); //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truenotifyAll(); //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;} @Overridepublic 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;} @Overridepublic 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........0
Thread-1........1
Thread-3........0
Thread-0........1
Thread-2........0
Thread-1........1
Thread-3........0
Thread-0........1
Thread-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;} @Overridepublic 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;} @Overridepublic 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........1
Thread-3........0
Thread-0........1
Thread-2........0
Thread-1........1
Thread-3........0
Thread-0........1
Thread-2........0