线程交互

使用synchronized方式进行线程交互，用到的是同步对象的wait,notify和notifyAll方法

Lock也提供了类似的解决办法，首先通过lock对象得到一个Condition对象，然后分别调用这个Condition对象的：await, signal,signalAll 方法

注意：不是Condition对象的wait,nofity,notifyAll方法,是await,signal,signalAll
package multiplethread;
  
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
  
public class TestThread {
  
    public static String now() {
        return new SimpleDateFormat("HH:mm:ss").format(new Date());
    }
  
    public static void log(String msg) {
        System.out.printf("%s %s %s %n", now() , Thread.currentThread().getName() , msg);
    }
  
    public static void main(String[] args) {
        Lock lock = new ReentrantLock();
        Condition condition = lock.newCondition();
         
        Thread t1 = new Thread() {
            public void run() {
                try {
                    log("线程启动");
                    log("试图占有对象：lock");
  
                    lock.lock();
  
                    log("占有对象：lock");
                    log("进行5秒的业务操作");
                    Thread.sleep(5000);
                    log("临时释放对象 lock， 并等待");
                    condition.await();
                    log("重新占有对象 lock，并进行5秒的业务操作");
                    Thread.sleep(5000);
  
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    log("释放对象：lock");
                    lock.unlock();
                }
                log("线程结束");
            }
        };
        t1.setName("t1");
        t1.start();
        try {
            //先让t1飞2秒
            Thread.sleep(2000);
        } catch (InterruptedException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        Thread t2 = new Thread() {
  
            public void run() {
                try {
                    log("线程启动");
                    log("试图占有对象：lock");
  
                    lock.lock();
  
                    log("占有对象：lock");
                    log("进行5秒的业务操作");
                    Thread.sleep(5000);
                    log("唤醒等待中的线程");
                    condition.signal();
  
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    log("释放对象：lock");
                    lock.unlock();
                }
                log("线程结束");
            }
        };
        t2.setName("t2");
        t2.start();
    }
  
}