java - 基于redis开发的分布式锁，没达到预期效果.
思路是用redis的setNX来获取锁，并加上超时时间，在使用完后删除key来释放锁，没获取到锁的就一直轮询setNX来获取锁直到获取成功，但是每次删除完key之后并没有线程获取到了锁。不知道是什么原因。
代码放出来：
public class RedisLock {
public static void lock(String key){
lock(key,60);
}
public static void lock(String key,int time){
Jedis jedis = RedisUtil.getClient();
try {
for (;;) {
//这一步在unlock以后还一直返回的NULL并没有返回OK！！！
String result = jedis.set(key, "1", "NX", "EX", time);
System.out.println(result);
if("OK".equals(result)){
break;
}
Thread.sleep(300);
}
} catch (Exception e) {
e.printStackTrace();
} finally{
jedis.close();
}
}
public static void unLock(String key){
Jedis jedis = RedisUtil.getClient();
try {
jedis.del(key);
} catch (Exception e) {
e.printStackTrace();
} finally{
jedis.close();
}
}
public static void main(String[] args) throws Exception{
System.out.println(RedisUtil.getClient().del("seckill"));
//开启100条线程去抢购1000个商品
for (int i = 0; i < 100; i++) {
new SeckillThread(i).start();
}
while(Thread.activeCount()>1){
Thread.sleep(1000);
}
System.out.println("还剩商品数量："+SeckillServiceImpl.goodNum);
}
}
class SeckillServiceImpl{
//商品总数
public static int goodNum = 1000;
public void kill(){
if(goodNum>0){
goodNum--;
}
}
public int getGoodNum(){
return goodNum;
}
}
class SeckillThread extends Thread{
private int i;
public SeckillThread(int i) {
this.i = i;
}
@Override
public void run() {
try {
SeckillServiceImpl seckillService = new SeckillServiceImpl();
System.out.println("线程["+i+"]加锁");
RedisLock.lock("seckill");
seckillService.kill();
} catch (Exception e) {
e.printStackTrace();
} finally {
System.out.println("线程["+i+"]释放锁");
RedisLock.unLock("seckill");
}
}
}
