java并發(fā)編程協(xié)作有兩種方式：
- 利用Object對(duì)象下面的wait()仲锄、notify()或者notifyAll()
- 利用Condition的await()劲妙、singnal()或者singnalAll()
其中需要注意的是：
對(duì)于方式1、調(diào)用wait()儒喊、notify()或者notifyAll() 必須在同步塊或者同步方法中進(jìn)行（synchronized塊或者synchronized方法）镣奋。
對(duì)于方式2、await()怀愧、singnal()或者singnalAll()必須在lock()和unlock()方法中進(jìn)行侨颈。
下面以常見的生成著和消費(fèi)者模型為例余赢，說明這兩種方式的使用。我們以購(gòu)物車為例哈垢，當(dāng)購(gòu)物車為空的時(shí)候妻柒，不允許從購(gòu)物車中拿操作，當(dāng)購(gòu)物車滿5個(gè)商品的時(shí)候?yàn)闈M温赔，不允許再放入商品蛤奢。本例僅僅為說明以上兩個(gè)方式的使用，不具有說明實(shí)際意義
使用方式1
ShoppingCar.java
public class ShoppingCar {
private Queue<String> queue = null;
Lock lock = new ReentrantLock();
public ShoppingCar(Queue<String> queue) {
super();
this.queue = queue;
}
public void getGood(String i){
synchronized (queue) {
System.out.println("current queue size is "+queue.size()+" car"+i+" start get good");
while(queue.isEmpty()){
try {
System.out.println("car "+i+" get good stop");//當(dāng)queue空的時(shí)候陶贼，等待啤贩，并讓出對(duì)象鎖
queue.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
String g = queue.poll();
System.out.println("car "+i+" get good "+ g +" suceed");
queue.notifyAll();
}
}
public void addGood(String i,String g){
synchronized (queue) {
System.out.println("current queue size is "+queue.size()+" car"+i+" start add "+g);
while(queue.size()>=5){
try {
System.out.println("car"+i+" add"+g+" stop");//當(dāng)queue滿的時(shí)候，等待拜秧，并讓出對(duì)象鎖
queue.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("car "+i+" add "+g+" suceed");
queue.add(g);
queue.notifyAll();
}
}
}
使用方式2
ShoppingCar2.java
public class ShoppingCar2 {
private Queue<String> queue = null;
Lock lock = new ReentrantLock();
Condition empty = lock.newCondition();
Condition full = lock.newCondition();
public ShoppingCar2(Queue<String> queue) {
super();
this.queue = queue;
}
public void getGood(String i){
lock.lock();
try{
System.out.println("current queue size is "+queue.size()+" car"+i+" start get good");
while(queue.isEmpty()){
try {
System.out.println("car "+i+" get good stop");//當(dāng)queue空的時(shí)候痹屹，等待，并讓出對(duì)象鎖
empty.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
String g = queue.poll();
System.out.println("car "+i+" get good "+ g +" sssuceed");
full.signalAll();
}finally{
lock.unlock();
}
}
public void addGood(String i,String g){
lock.lock();
try{
System.out.println("current queue size is "+queue.size()+" car"+i+" start add "+g);
while(queue.size()>=5){
try {
System.out.println("car"+i+" add "+g+" stop");//當(dāng)queue滿的時(shí)候枉氮，等待志衍，并讓出對(duì)象鎖
full.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("car "+i+" add "+g+" suceed");
queue.add(g);
empty.signalAll();
}finally{
lock.unlock();
}
}
}
調(diào)用：
public class Demo {
public static void main(String[] args) {
ShoppingCar2 car = new ShoppingCar2(new LinkedList<String>());
ExecutorService addser = Executors.newCachedThreadPool();
ExecutorService getser = Executors.newCachedThreadPool();
for(int i=0;i<10;i++)
addser.submit(new AddThread(i, car));
for(int i=0;i<10;i++)
getser.submit(new GetThread(i, car));
addser.shutdown();
getser.shutdown();
}
public static class AddThread implements Runnable{
ShoppingCar2 car = null;
int id;
public AddThread(int i,ShoppingCar2 car){
this.car = car;
this.id = i;
}
@Override
public void run() {
while(true){
car.addGood(String.valueOf(id),String.valueOf((int)(100*Math.random())));
try {
Thread.currentThread().sleep((int)(1000*Math.random())*10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public static class GetThread implements Runnable{
ShoppingCar2 car = null;
int id;
public GetThread(int i,ShoppingCar2 car){
this.car = car;
this.id = i;
}
@Override
public void run() {
while(true){
car.getGood(String.valueOf(id));
try {
Thread.currentThread().sleep((int)(1000*Math.random())*10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
說明：購(gòu)物車有兩個(gè)操作，一個(gè)get商品聊替、一個(gè)add商品楼肪、在Demo類中我們有一個(gè)AddThread類專門去add商品、一個(gè)GetThread類專門去get商品惹悄。main方法中春叫，我們分別產(chǎn)出10個(gè)Get線程和10個(gè)Add線程去執(zhí)行商品的add和get操作。
商品用一個(gè)隨機(jī)生成的數(shù)字代替泣港，get和add商品的時(shí)間也隨機(jī)指定暂殖。執(zhí)行結(jié)果如下：
current queue size is 0 car0 start add 53
car 0 add 53 suceed
current queue size is 1 car3 start add 58
car 3 add 58 suceed
current queue size is 2 car4 start add 82
car 4 add 82 suceed
current queue size is 3 car2 start add 33
car 2 add 33 suceed
current queue size is 4 car6 start add 99
car 6 add 99 suceed
current queue size is 5 car7 start add 53
car7 add 53 stop</span>
current queue size is 5 car1 start add 45
car1 add 45 stop
current queue size is 5 car8 start add 59
car8 add 59 stop
current queue size is 5 car5 start add 58
car5 add 58 stop
current queue size is 5 car9 start add 88
car9 add 88 stop
current queue size is 5 car0 start get good
car 0 get good 53 sssuceed
current queue size is 4 car3 start get good
car 3 get good 58 sssuceed
current queue size is 3 car1 start get good
car 1 get good 82 sssuceed
current queue size is 2 car2 start get good
car 2 get good 33 sssuceed
current queue size is 1 car4 start get good
car 4 get good 99 sssuceed
car 7 add 53 suceed</span>
car 1 add 45 suceed
car 8 add 59 suceed
car 5 add 58 suceed
car 9 add 88 suceed
current queue size is 5 car5 start get good
car 5 get good 53 sssuceed
current queue size is 4 car6 start get good
car 6 get good 45 sssuceed
current queue size is 3 car8 start get good
car 8 get good 59 sssuceed
current queue size is 2 car9 start get good
car 9 get good 58 sssuceed
current queue size is 1 car7 start get good
car 7 get good 88 sssuceed
current queue size is 0 car4 start add 88
car 4 add 88 suceed
current queue size is 1 car9 start get good
car 9 get good 88 sssuceed
current queue size is 0 car5 start add 1
car 5 add 1 suceed
current queue size is 1 car9 start get good
car 9 get good 1 sssuceed
current queue size is 0 car9 start get good
car 9 get good stop
current queue size is 0 car1 start add 70
car 1 add 70 suceed
我們選取部分的結(jié)果分析，看標(biāo)注的兩個(gè)地方
car7 add 53 stop
執(zhí)行到這里時(shí)当纱，購(gòu)物車滿了呛每，沒有添加到購(gòu)物車
car 7 add 53 suceed
到這里時(shí)候，由于有線程在get商品坡氯，此時(shí)購(gòu)物車中商品小于5個(gè)了晨横，可以添加商品了，就添加成功
