很有意思的一个题目：关于多线程！！
我今天自己写了一下这个小程序
这个题目的要求是 ：
有4对家庭，分别有爸爸，妈妈，儿子，女儿
爸爸们专门负责往盘子里放苹果，妈妈们专门负责往盘子里放橘子，
儿子门专门吃盘子里的橘子；女儿们专门吃盘子里的苹果；
注意；盘子里最多只能有10个水果，而且每次只能放或者取一个水果；
就这么多了，代码在下面，运行出现了点问题，好象有时候 某些方法被访问多次，
有兴趣的可以运行一下代码，帮我分析一下原因，谢谢 了
class ThreadTest
{
public static void main(String[] args)
{
Plate q=new Plate();
Father f1=new Father(q);
Father f2=new Father(q);
Father f3=new Father(q);
Father f4=new Father(q);
Mother m1=new Mother(q);
Mother m2=new Mother(q);
Mother m3=new Mother(q);
Mother m4=new Mother(q);
Son s1=new Son(q);
Son s2=new Son(q);
Son s3=new Son(q);
Son s4=new Son(q);
Daughter d1=new Daughter(q);
Daughter d2=new Daughter(q);
Daughter d3=new Daughter(q);
Daughter d4=new Daughter(q);
f1.start();
f2.start();
f3.start();
f4.start();
m1.start();
m2.start();
m3.start();
m4.start();
s1.start();
s2.start();
s3.start();
s4.start();
d1.start();
d2.start();
d3.start();
d4.start();
}
}
class Father extends Thread
{
Plate q;
Father(Plate q)
{
this.q=q;
}
public void run()
{
while(true)
{
q.putApple(q.apple);
System.out.println(Thread.currentThread().getName()+ " put one apple:
the number of apple in the plate: "+q.apple);
}
}
}
class Mother extends Thread
{
Plate q;
Mother(Plate q)
{
this.q=q;
}
public void run()
{
while(true)
{
q.putOrange(q.orange);
System.out.println(Thread.currentThread().getName()+ " put one
orange:the number of orange in the plate: "+q.orange);
}
}
}
class Son extends Thread
{
Plate q;
Son(Plate q)
{
this.q=q;
}
public void run()
{
while(true)
{
System.out.println(Thread.currentThread().getName()+ " get one orange:the
number of orange in the plate: "+q.getOrange());
}
}
}
class Daughter extends Thread
{
Plate q;
Daughter(Plate q)
{
this.q=q;
}
public void run()
{
while(true)
{
System.out.println(Thread.currentThread().getName()+ "Daughter get one
apple:the number of apple in the plate: "+q.getApple());
}
}
}
class Plate
{
int apple=0;
int orange=0;
int pFull=10;
public synchronized void putApple(int i)
{
if(pFull <11 && pFull> 0)
{
i++;
apple=i;
pFull--;
notifyAll();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public synchronized int getApple()
{
if(apple <1 || apple> 10)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
pFull++;
notifyAll();
apple--;
return apple;
}
public synchronized void putOrange(int i)
{
if(pFull <11 && pFull> 0)
{
i++;
orange=i;
pFull--;
notifyAll();
}
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
public synchronized int getOrange()
{
while(orange <1 || orange> 11)
{
try
{
wait();
}
catch(Exception e)
{
e.printStackTrace();
}
}
pFull++;
notifyAll();
orange--;
return orange;
}
}
[解决办法]
UP下吧
[解决办法]
有人帮解释以下么？
[解决办法]
mark
[解决办法]
up
[解决办法]
使用一个Vector,里面存储橘子或者苹果的对象(当size() < 10),在使用Vector的时候synchronized
[解决办法]
因为盘子会有共享互斥,
所以你应该把关注的焦点放在它的身上.
[解决办法]
add some code into your "get(),set() "
satatic Vector vector=new Vector(10); //class variable
such as:
synchronized(vector.size()...) {
.....// do something with your
}
[解决办法]
q.putOrange(q.orange);
不能保证q.orange的同步吧？
public synchronized void putOrange(int i）改成下面的样子可以吗？
public synchronized int putOrange(）
返回值是q.orange。
[解决办法]
哪有这样控制同步的？
开始没东西时2种(8个)get线程都被block，2种(8个)put线程竞争。假设其中一个putApple得胜，将放入1苹果并唤醒其他线程，继续竞争，若此时某个getOrange获胜，注意到将从wait代码块后面执行，于是程序将拿取一个桔子。。。明显的逻辑错误。
办法：
在plate定义两个list（数组或者Integer也可），一个放桔子一个放苹果，用这两个东西来分别控制两对get/put方法。
[解决办法]
操作系统 课上的例子……
[解决办法]
试试看，不一定符合你的要求！
public class ThreadTest
{
public static void main(String[] args)
{
Fruits q = new Fruits();
Father f1=new Father(q);
Father f2=new Father(q);
Father f3=new Father(q);
Father f4=new Father(q);
Mother m1=new Mother(q);
Mother m2=new Mother(q);
Mother m3=new Mother(q);
Mother m4=new Mother(q);
Son s1=new Son(q);
Son s2=new Son(q);
Son s3=new Son(q);
Son s4=new Son(q);
Daughter d1=new Daughter(q);
Daughter d2=new Daughter(q);
Daughter d3=new Daughter(q);
Daughter d4=new Daughter(q);
f1.start();
f2.start();
f3.start();
f4.start();
m1.start();
m2.start();
m3.start();
m4.start();
s1.start();
s2.start();
s3.start();
s4.start();
d1.start();
d2.start();
d3.start();
d4.start();
}
}
class Father extends Thread
{
Fruits fruit;
Father(Fruits fruit)
{
this.fruit = fruit;
}
public void run()
{
while(true)
{
fruit.setApple();
System.out.println(Thread.currentThread().getName() +
" put one apple: the number of apple in the plate: " + fruit.appleNumber +
"the number of full in the plate: " + fruit.full);
}
}
}
class Mother extends Thread
{
Fruits fruit;
Mother(Fruits fruit)
{
this.fruit = fruit;
}
public void run()
{
while(true)
{
fruit.setOrange();
System.out.println(Thread.currentThread().getName() +
" put one oranger: the number of orange in the plate: " + fruit.orangeNumber +
"the number of full in the plate: " + fruit.full);
}
}
}
class Son extends Thread
{
Fruits fruit;
Son(Fruits fruit)
{
this.fruit = fruit;
}
public void run()
{
while(true)
{
fruit.getOrange();
System.out.println(Thread.currentThread().getName() +
" get one orange: the number of orange in the plate: " + fruit.orangeNumber +
"the number of full in the plate: " + fruit.full);
}
}
}
class Daughter extends Thread
{
Fruits fruit;
Daughter(Fruits fruit)
{
this.fruit = fruit;
}
public void run()
{
while(true)
{
fruit.getApple();
System.out.println(Thread.currentThread().getName() +
" get one apple: the number of apple in the plate: " + fruit.appleNumber +
"the number of full in the plate: " + fruit.full);
}
}
}
class Fruits
{
int appleNumber = 0;
int orangeNumber = 0;
int full = 0;
public synchronized int setApple()
{
if(full < 10 && full > = 0 && appleNumber < 10)
{
appleNumber += 1;
full++;
}
return appleNumber;
}
public synchronized int getApple()
{
if(full > = 1 && full <=10 && appleNumber > = 1)
{
appleNumber -= 1;
full--;
}
return appleNumber;
}
public synchronized int setOrange()
{
if(full < 10 && full > = 0 && orangeNumber < 10)
{
orangeNumber += 1;
full++;
}
return orangeNumber;
}
public synchronized int getOrange()
{
if(full > = 1 && full <=10 && orangeNumber > = 1)
{
orangeNumber -= 1;
full--;
}
return orangeNumber;
}
public synchronized int getFull()
{
return appleNumber + orangeNumber;
}
}
