两个线程交替输出1-100

public class JiOuTest {
    public static void main(String[] args) {
        PrintThread p=new PrintThread();
        Thread t1=new Thread(p);
        Thread t2=new Thread(p);
        t1.start();
        t2.start();
    }
}

// 类锁
   class PrintThread implements Runnable {
        private static Object lock = new Object();
        private static  int num = 0;
        @Override
        public void run() {
            synchronized (lock) {
                while (num < 100) {
                    System.out.println(Thread.currentThread().getName() + "打印：" + ++num);
                    lock.notifyAll();
                    try {
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

需要注意的是：
不能是以Integer为共享对象，因为等等调用wait、notify需要是同一个对象，而integer++后变了

wait() notify() 需要是以java对象的方法，不是线程的方法

i.wait(); // 不能是直接wait()

i.notify() // 唤醒wait方法

public class ProductCustomer_jiou {
    public static void main(String[] args) {
        Num01 i=new Num01(1);
        Thread t1=new Thread(new Ji(i));
        Thread t2=new Thread(new Ou(i));
        t1.start();
        t2.start();
    }
}
class Num01{
    Integer num;
    public Num01(Integer i){
        this.num=i;
    }
}

class Ji implements Runnable{
   Num01 i;
    public Ji(Num01 i){
        this.i=i;
    }
    @Override
    public void run(){
        while(i.num<100){
            synchronized(i){
                if(i.num%2==0){
                    try{
                        i.wait();
                    }catch(InterruptedException e){
                        e.printStackTrace();
                    }
                }
                System.out.println(Thread.currentThread().getName()+" "+i.num);
                i.num++;
                i.notify();
            }
        }
    }
}

class Ou implements Runnable{
   Num01 i;
    public Ou(Num01 i){
        this.i=i;
    }
    @Override
    public void run(){
        while(i.num<100){
            synchronized(i){
                if(i.num%2==1){
                    try{
                        i.wait();
                    }catch(InterruptedException e){
                        e.printStackTrace();
                    }
                }
                System.out.println(Thread.currentThread().getName()+" "+i.num);
                i.num++;
                i.notify();
            }
        }
    }
}