要實作買票系統，一定要用到多執行緒，因為火車站售票處不可能只有一個賣票口，那么如何防止兩個口或多個口同時賣出一張票就是一個必須解決的問題，這里我們可以用到synchrnized同步代碼塊也就是鎖，來解決這個問題，
synchrnized:同步，可以修飾代碼塊和方法，修飾的代碼塊或方法一旦被某個執行緒訪問，則直接鎖住，其他執行緒將無法訪問，只能等著，簡言之：就是一把鎖
synchrnized(鎖物件)
{
代碼塊
}
注意： 鎖物件需要對所有執行緒共享
- 同步： 安全性高 效率低
- 非同步：效率高 安全性低
也可以給方法前加synchrnized修飾符，把整個方法都變成同步方法，
下面是實作售票系統的代碼：
package maipiao;
public class tickets {
@Override
public String toString() {
return "["+start + "->" + end + ", price=" + price + "]";
}
public String getStart() {
return start;
}
public void setStart(String start) {
this.start = start;
}
public String getEnd() {
return end;
}
public void setEnd(String end) {
this.end = end;
}
public int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
private String start;
private String end;
private int price;
public tickets(String start, String end, int price) {
super();
this.start = start;
this.end = end;
this.price = price;
}
public tickets() {}
}
package maipiao;
import java.util.ArrayList;
public class xitong {
public xitong() {}
private ArrayList<tickets> list = new ArrayList<>();
private String[] start = {"哈爾濱","廣東","湖南","安徽","北京"};
private String[] end = {"深圳","澳門","臺灣","香港"};
public void addliebiao()
{
for(int i=0;i<100;i++) {
int r1 = (int) (Math.random()*start.length);
int r2 = (int)(Math.random()*end.length);
int price = (r1*r2)+100;
list.add(new tickets(start[r1],end[r2],price));
}
}
public tickets getTickets() {
return list.size() == 0 ? null : list.remove(0);
}
}
package maipiao;
public class chuangkou implements Runnable {
public void run() {
try {
method();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private synchronized void method() throws InterruptedException {
Thread.sleep(100);
xitong xt = new xitong();
xt.addliebiao();
while(true){
tickets ticket = xt.getTickets();
if(ticket==null) {
System.out.println("抱歉"+Thread.currentThread().getName()+"票已經售完");
break;
}else {
System.out.println("從"+Thread.currentThread().getName()+"賣出"+ticket+"的票");
}
}
}
}
package maipiao;
/**
*
* @author fzl
* @Dare 2020-11-21 19:22:23
* @Description 售票系統
*
*/
public class Main {
public static void main(String[] args) {
chuangkou cg1 = new chuangkou();
chuangkou cg2 = new chuangkou();
chuangkou cg3 = new chuangkou();
Thread t1 = new Thread(cg1);
Thread t2 = new Thread(cg2);
Thread t3 = new Thread(cg3);
t1.setName("一號口");
t2.setName("二號口");
t3.setName("三號口");
t1.start();
t2.start();
t3.start();
}
}
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