main方法
public class main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Ticket ti=new Ticket();
Thread t1=new Thread(ti);
Thread t2=new Thread(ti);
Thread t3=new Thread(ti);
Thread t4=new Thread(ti);
t1.start();
t2.start();
t3.start();
t4.start();
}
}
runable实现类
public class Ticket implements Runnable {
private int all=100;
@Override
public void run() {
// TODO Auto-generated method stub
while(true){
if(all>0)
{
System.out.println(Thread.currentThread().getName()+"ticket"+all);
all--;
}
else
break;
}
}
}
输出结果
Thread-0ticket100
Thread-0ticket99
Thread-0ticket98
Thread-2ticket100
Thread-2ticket96
Thread-2ticket95
Thread-2ticket94
Thread-2ticket93
Thread-2ticket92
Thread-2ticket91
Thread-2ticket90
Thread-2ticket89
Thread-2ticket88
Thread-2ticket87
Thread-2ticket86
Thread-2ticket85
Thread-2ticket84
Thread-2ticket83
Thread-2ticket82
Thread-2ticket81
Thread-2ticket80
Thread-2ticket79
Thread-2ticket78
Thread-2ticket77
Thread-2ticket76
Thread-2ticket75
Thread-2ticket74
Thread-3ticket100
Thread-3ticket72
Thread-3ticket71
Thread-1ticket100
Thread-3ticket70
Thread-2ticket73
Thread-2ticket67
Thread-2ticket66
Thread-2ticket65
Thread-2ticket64
Thread-2ticket63
Thread-2ticket62
Thread-2ticket61
Thread-2ticket60
Thread-2ticket59
Thread-2ticket58
Thread-2ticket57
Thread-0ticket97
Thread-2ticket56
Thread-3ticket68
Thread-3ticket53
Thread-3ticket52
Thread-1ticket69
Thread-3ticket51
Thread-2ticket54
Thread-0ticket55
Thread-2ticket48
Thread-3ticket49
Thread-1ticket50
Thread-3ticket45
Thread-2ticket46
Thread-0ticket47
Thread-2ticket42
Thread-2ticket40
Thread-2ticket39
Thread-2ticket38
Thread-2ticket37
Thread-2ticket36
Thread-2ticket35
Thread-2ticket34
Thread-3ticket43
Thread-1ticket44
Thread-3ticket32
Thread-2ticket33
Thread-0ticket41
Thread-2ticket29
Thread-3ticket30
Thread-1ticket31
Thread-3ticket26
Thread-3ticket24
Thread-3ticket23
Thread-3ticket22
Thread-3ticket21
Thread-3ticket20
Thread-2ticket27
Thread-2ticket18
Thread-2ticket17
Thread-2ticket16
Thread-2ticket15
Thread-2ticket14
Thread-2ticket13
Thread-2ticket12
Thread-2ticket11
Thread-2ticket10
Thread-2ticket9
Thread-2ticket8
Thread-2ticket7
Thread-2ticket6
Thread-2ticket5
Thread-2ticket4
Thread-2ticket3
Thread-2ticket2
Thread-2ticket1
Thread-0ticket28
Thread-3ticket19
Thread-1ticket25
为什么100出现了4次，非首次输出的其他输出100的时候，顶替掉了原来的数值，却在结尾输出。不是公用一个ticket的吗，为什么后面还会出现100.。。
线程在工作时，会先从主内存中读取数据，再把all的值从主内存中拷贝一份到自己的线程内存中，然后在运行一段时间后往主内存中写入已经改变的all的值，由于线程运行是抢占式的，t1线程还没来得及通知主线程中all的值已经改变了，t2线程就已经从主内存中又拷贝了一份all的变量，所以就变成这种状况了，我个人理解的，说的不对的地方请见谅。
多线程处理是非原子性的操作，例如第一次all的值为100，当线程1从主内从中获取all为100，二all--并没有执行，此时线程2从祝内存中获取的all也为100
，这样就造成了数据会出现重复的
你的程序中all=30?是不是写错了，对于结果，由于多个线程共享ticket，输出的结果具有一定的随机性，比如线程1：读到all=100,还没有执行的输出,此时线程2已经读到100，
并且ticket减1,但是ticket减1之后的结果线程1并不知道，还是继续打印ticket=100，因此就有两个100；你多执行几次就会发现每次的结果会不一样的。
因为你是多线程调用ticket中的run( )方法，并没有加锁，所有有可能在Thread-0的时间片段到的时候可能是刚刚执行完循环的判断，没有输出此时的指，也没有对all的值更改。
然后Thread-1又开始执行，并行对一个不加锁的数据更改结果是随机的
因为你是多线程调用ticket中的run( )方法，并没有加锁，
加个volatile试试
使用锁来控制线程的安全
加个volatile试试，可以去看一下jmm（java 内存模型）相关的内容。
线程安全问题,可以考虑加同步锁.
说白了就是线程安全的问题，多线程运行用一段代码，并没有设置同步锁，所以运行结果有随机性，看抢到的时间片先后而运行