一、java的notify与wait

package org.calonlan.soulpower;public class MyThreadTest implements Runnable {private String name;private Object prev;private Object self;public MyThreadTest(String name, Object prev, Object self) {super();this.name = name;this.prev = prev;this.self = self;}@Overridepublic void run() {int count = 10;while (count > 0) {synchronized (prev) {//请求获得上一个的锁synchronized (self) {//请求获得自己的锁System.out.println(name+"--"+count);count--;try {Thread.sleep(1);//这里测试sleep，sleep只会让当前线程让出cpu、内存等资源，但不会释放锁} catch (InterruptedException e) {e.printStackTrace();}self.notify();//通知等待sefl的锁的线程可以启动了，同时在synchronized (self)块执行完成后释放self锁，程序继续执行}try {prev.wait();//这里释放prev锁，并且程序进入阻塞状态。等在notify的时候重新启动程序执行} catch (InterruptedException e) {e.printStackTrace();}}}}public static void main(String[] args) throws Exception {Object a = new Object();Object b = new Object();Object c = new Object();MyThreadTest ta = new MyThreadTest("A", c, a);MyThreadTest tb = new MyThreadTest("B", a, b);MyThreadTest tc = new MyThreadTest("C", b, c);new Thread(ta).start();Thread.sleep(10);//---------{new Thread(tb).start();//   | Thread.sleep(10);//---------{三个Thread.sleep()是让主线程中保证三个线程按顺序启动new Thread(tc).start();//   |Thread.sleep(10);//---------{}}

二、java的condition中的signal与await

package org.calonlan.soulpower;import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;public class BoundedBufferTest {final Lock lock = new ReentrantLock();//定义一个锁final Condition notFull = lock.newCondition();//锁中的状态，用来标识notfullfinal Condition notEmpty = lock.newCondition();//锁中的状态，用来标识notemptyfinal Object[] items = new Object[100];//队列int putptr, takeptr, count;public void put(Object x) throws Exception {lock.lock();/*在lock与unlock之间的代码才能保证线程安全*/try {// condition需要在while中判断while (count == items.length)notFull.await();//队列满的了时候用notFull来阻塞程序/*接收到notFull的signal或者队列本来就不满执行下面的代码*/items[putptr] = x;if (++putptr == items.length)putptr = 0;++count;notEmpty.signal();} finally {/*在lock与unlock之间的代码才能保证线程安全*/lock.unlock();}}public Object take() throws Exception {lock.lock();/*在lock与unlock之间的代码才能保证线程安全*/try {while (count == 0)notEmpty.await();//使用notemty来阻塞线程（如果count==0的时候），这里一定要用while来做判断Object x = items[takeptr];if (++takeptr == items.length)takeptr = 0;--count;notFull.signal();return x;} finally {/*在lock与unlock之间的代码才能保证线程安全*/lock.unlock();}}static class Thread1 extends Thread {private BoundedBufferTest BoundedBufferTest;public Thread1(BoundedBufferTest boundedBufferTest) {super();BoundedBufferTest = boundedBufferTest;}@Overridepublic void run() {int count = 0;try {while (true) {System.out.println(count + "放入");BoundedBufferTest.put(count++);Thread.sleep(100);}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}static class Thread2 extends Thread {private BoundedBufferTest BoundedBufferTest;public Thread2(BoundedBufferTest boundedBufferTest) {super();BoundedBufferTest = boundedBufferTest;}@Overridepublic void run() {try {while (true) {System.out.println(Thread.currentThread().getName()+ BoundedBufferTest.take());Thread.sleep(10000);}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}public static void main(String[] args) {BoundedBufferTest boundedBufferTest = new BoundedBufferTest();Thread2 thread2 = new Thread2(boundedBufferTest);Thread1 thread1 = new Thread1(boundedBufferTest);thread1.start();thread2.start();}
}