java Thread线程tickets问题
论文问答
1
刚学thread，怎么控制台输出会有重复的数目？
public class Ticket implements Runnable{
public static int count = 5;
private String name;
public void run(){
for(int i=0;i<=4;i++){
try{
Thread.sleep(1000);
}catch(Exception e){
e.printStackTrace();
}
if(count >0 ){
System.out.println(Thread.currentThread().getName()+",count= " + this.count--);
}
}
}
public Ticket(){
}
public Ticket(String name){
this.name = name;
}
public static void main(String[] args){
Ticket ticket = new Ticket();
new Thread(ticket,"A").start();
new Thread(ticket,"B").start();
new Thread(ticket,"C").start();
}
}
consoles： B,count= 5 A,count= 5 C,count= 4 B,count= 3 A,count= 2 C,count= 1
-
public static int count = 5; 改成 public static Integer count = 5; if(count >0 ){ System.out.println(Thread.currentThread().getName()+",count= " + this.count--); } 改成 synchronized(count){//增加同步锁，当一个线程访问count时，其他不能访问 if(count >0 ){ System.out.println(Thread.currentThread().getName()+",count= " + this.count--); } }
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