package com.pb.thread.demo5;/**使用synchronized * 一個線程加一運算，一個線程做減法運算，多個線程同時交替運行 *  * @author Denny * */public class Count {    PRivate int num = 0;    private boolean flag = false; // 標識    //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; //設置標識為true        notifyAll(); //喚醒所有在線程池中凍結的線程，會把所有都喚醒            }    //減法    public synchronized void sub() {        while (!flag) {            try {                wait();            } catch (InterruptedException e) {                e.printStackTrace();            }        }        this.num--; //減        System.out.println(Thread.currentThread().getName() + "........" + this.num);        this.flag=false; //設置標識為true        notifyAll(); //喚醒所有在線程池中凍結的線程，會把所有都喚醒    }}

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();        }    }} 

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();    }}

Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0

package com.pb.thread.demo4;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * 一個線程加一運算，一個線程做減法運算，多個線程同時交替運行 * @author Denny * */public class Count {    private int num = 0;    private boolean flag=false; // 標識    Lock lock = new ReentrantLock(); // 鎖    Condition add = lock.newCondition(); // 加法鎖    Condition sub = lock.newCondition();// 減法鎖    public void add() {        lock.lock();// 鎖上        try {            while (flag) {  //循環判斷                add.await();            }            this.num++;            System.out.println(Thread.currentThread().getName() + "........" + this.num);            this.flag = true; // 設置標識            sub.signal(); // 喚醒指定線程        } catch (InterruptedException e) {            e.printStackTrace();        }finally{            lock.unlock();        }            }    public void sub() {        lock.lock();// 鎖上        try {            while (!flag) {//循環判斷                sub.await();            }            this.num--;            System.out.println(Thread.currentThread().getName() + "........" + this.num);            this.flag = false; // 設置標識            add.signal(); // 喚醒指定線程        } 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();    }}

Thread-1........1Thread-3........0Thread-0........1Thread-2........0Thread-1........1Thread-3........0Thread-0........1Thread-2........0