正确的写法:public class mainclass {
public static void main(String[] args) {
Train A=new Train();
Train B=new Train();
Train C=new Train();
A.start();
B.start();
C.start();
}
}
class Train extends Thread{
public static int ticket=7;
public void run(){
{
A();
}
}
public synchronized void A(){
while (ticket>0){
System.out.println("第"+this.getName()+"站卖出第"+ticket--+"张票");
}
}
}
出现问题的写法:public class mainclass {
public static void main(String[] args) {
Train A=new Train();
Train B=new Train();
Train C=new Train();
A.start();
B.start();
C.start();
}
}
class Train extends Thread{
public static int ticket=7;
public void run(){
{
A();
}
}
public synchronized void A(){
while (ticket>0){
System.out.println("第"+this.getName()+"站卖出第"+ticket+"张票");
ticket--;
}
}
}
在A()函数之中ticket--的位置不同却出现了两种结果。一种将ticket--写在输出语句里,结果正确,但一种写在输出语句之外就会出现线程同步问题,可是我已经在函数前面加了synchronized,为什么会这样,按理来说两者应该一样啊。