| import redis.clients.jedis.Jedis;
import java.text.SimpleDateFormat;
import java.util.Collections;
import java.util.Date;
/**
* @author jason
* @date 2019/8/17 16:09
*/
public class RedisSetNXTest extends Thread{
private static final String LOCK_SUCCESS = "OK";
private static final String SET_IF_NOT_EXIST = "NX";
private static final String SET_WITH_EXPIRE_TIME = "PX";
private String auctionCode;
public RedisSetNXTest
(String auctionCode) {
super(auctionCode);
this.auctionCode = auctionCode;
}
private static int bidPrice = 100;
public static void initStock(Jedis jedis,String size)
{
jedis.set("StockSize",size);
}
public boolean subStock(Jedis jedis)
{
String value=jedis.get("StockSize");
int size=Integer.parseInt(value);
if((size-1)<0)
{
System.out.println("用户："+Thread.currentThread().getName() +"库存已经耗尽，抢购失败"+getSystemTime());
return false;
}
System.out.println("用户："+Thread.currentThread().getName() +"当前库存="+size+"==抢购成功"+getSystemTime());
jedis.set("StockSize",--size+"");
return true;
}
public static void main(String[] args) {
System.out.println(Thread.currentThread().getName() + "主线程运行开始!");
//更改key为a的值
Jedis jedis=new Jedis("172.31.62.131",6379);
//初始化库存
initStock(jedis,"4");
//jedis.set("goodsprice","0");
//System.out.println("输出初始化值："+jedis.get("goodsprice")+getSystemTime());
jedis.close();
RedisSetNXTest thread1 = new RedisSetNXTest("A001");
RedisSetNXTest thread2 = new RedisSetNXTest("B001");
RedisSetNXTest thread3 = new RedisSetNXTest("C001");
RedisSetNXTest thread4 = new RedisSetNXTest("D001");
RedisSetNXTest thread5 = new RedisSetNXTest("E001");
thread1.start();
thread2.start();
thread3.start();
thread4.start();
thread5.start();
try{
thread1.join();
thread2.join();
thread3.join();
thread4.join();
thread5.join();
}catch(InterruptedException e){
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + "主线程运行结束!"+getSystemTime());
}
@Override
public void run() {
Jedis jedis=new Jedis("172.31.62.131",6379);
//尝试获取锁
boolean isOk= tryGetDistributedLock(jedis, "goods_lock", Thread.currentThread().getName() , 10000);
if(isOk) {
System.out.println("子线程"+this.auctionCode +"拿到锁"+getSystemTime());
subStock(jedis);
System.out.println("子线程"+this.auctionCode +"释放锁"+getSystemTime());
releaseDistributedLock(jedis, "goods_lock", Thread.currentThread().getName());
}else{
while(!isOk){
//System.out.println("子线程" + auctionCode + "未拿到锁"+getSystemTime());
isOk= tryGetDistributedLock(jedis, "goods_lock", Thread.currentThread().getName() , 10000);
try {
sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("子线程"+this.auctionCode +"拿到锁"+getSystemTime());
subStock(jedis);
System.out.println("子线程"+this.auctionCode +"释放锁"+getSystemTime());
releaseDistributedLock(jedis, "goods_lock", Thread.currentThread().getName());
}
jedis.close();
System.out.println(Thread.currentThread().getName() + "线程运行结束"+getSystemTime());
}
/**
* 业务逻辑处理
* */
public void doSomething(Jedis jedis)
{
String v = jedis.get("goodsprice");
Integer iv = Integer.valueOf(v);
//条件都给过
if(bidPrice > iv){
Integer bp = iv + 100;
//出价成功，事务未提交
jedis.set("goodsprice",String.valueOf(bp));
System.out.println("子线程"+this.auctionCode +", 出价："+ jedis.get("goodsprice") +"，出价时间：" +getSystemTime());
}else{
System.out.println("子线程"+this.auctionCode +"出价低于现有价格！"+getSystemTime());
}
}
/**
* 尝试获取分布式锁
* @param jedis Redis客户端
* @param lockKey 锁
* @param requestId 请求标识
* @param expireTime 超期时间
* @return 是否获取成功
*/
public boolean tryGetDistributedLock(Jedis jedis, String lockKey, String requestId, int expireTime) {
String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);
if (LOCK_SUCCESS.equals(result)) {
return true;
}
return false;
}
private static final Long RELEASE_SUCCESS = 1L;
/**
* 释放分布式锁
* @param jedis Redis客户端
* @param lockKey 锁
* @param requestId 请求标识
* @return 是否释放成功
*/
public boolean releaseDistributedLock(Jedis jedis, String lockKey, String requestId) {
String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1])else return 0 end";
Object result = jedis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId));
if (RELEASE_SUCCESS.equals(result)) {
return true;
}
return false;
}
public static String getSystemTime()
{
Date now = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//可以方便地修改日期格式
String times = dateFormat.format( now );
System.out.println(times);
return times;
}
} |
