public interface GoodsService {

 /**
  * 通过lua脚本实现的秒杀
  * @param skuCode 商品编码
  * @param buyNum 购买数量
  * @return 购买数量
  */
 Long flashSellByLuaScript(String skuCode,int buyNum);
 /**
  * 通过redis 事务 实现的秒杀
  * @param skuCode 商品编码
  * @param buyNum 购买数量
  * @return 购买数量
  */
 Long flashSellByRedisWatch(String skuCode,int buyNum);

}

import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.SessionCallback;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;

@Service
public class GoodsServiceImpl implements GoodsService {

 @Resource
 private StringRedisTemplate stringRedisTemplate;

 @Override
 public Long flashSellByLuaScript(String skuCode,int num) {
  //下面是lua脚本
  String luaScript ="local buyNum = ARGV[1]\n" +
    "local goodsKey = KEYS[1] \n" +
    "local goodsNum = redis.call('get',goodsKey) \n" +
    "if goodsNum >= buyNum \n" +
    "then redis.call('decrby',goodsKey,buyNum) \n" +
    "return buyNum \n" +
    "else \n" +
    "return '0'\n" +
    "end\n" +
    "\n" ;

  DefaultRedisScript<String> re = new DefaultRedisScript<String>();
  //设置脚本
  re.setScriptText(luaScript);
  //定义返回值类型，注意，如果没有这个定义，Spring不会返回结果
  re.setResultType(String.class);
  RedisSerializer<String> stringRedisSerializer = stringRedisTemplate.getStringSerializer();
  //执行LUA脚本
  String result = (String) stringRedisTemplate.execute(re, stringRedisSerializer, stringRedisSerializer, null);
  return Long.valueOf(result);
 }

 @Override
 public Long flashSellByRedisWatch(String skuCode,int num){

  SessionCallback<Long> sessionCallback = new SessionCallback<Long>() {
   @Override
   public Long execute(RedisOperations operations) throws DataAccessException {
    int result = num;
    //redis 乐观锁
    //我们观察商品编码是否发生改变
    operations.watch(skuCode);
    ValueOperations<String, String> valueOperations = operations.opsForValue();
    String goodsNumStr = valueOperations.get(skuCode);
    Integer goodsNum = Integer.valueOf(goodsNumStr);
    //标记一个事务块的开始。
    //事务块内的多条命令会按照先后顺序被放进一个队列当中，
    //最后由 EXEC 命令原子性(atomic)地执行。
    operations.multi();
    if (goodsNum >= num) {
     valueOperations.increment(skuCode, 0 - num);
    } else {
     result = 0;
    }
    //多条命令执行的结果集合
    List exec = operations.exec();
    if(exec.size()>0){
     System.out.println(exec);
    }
    return (long) result;
   }
  };
  return stringRedisTemplate.execute(sessionCallback);
 }
//省略 其他的方法


}

@ApiOperation(value = "用事务秒杀测试接口", notes = "用事务秒杀测试接口")
@RequestMapping(value = "/miaoTransaction", method = RequestMethod.GET)
@ResponseBody
 public Long miaoTransaction() {

  Long res = goodsService.flashSellByRedisWatch("xiaomi", 1);
  return res;
 }


 @ApiOperation(value = " 秒杀Lua测试接口", notes = "秒杀Lua测试接口")
 @RequestMapping(value = "/miaoLua", method = RequestMethod.GET)
 @ResponseBody
 public Long miaoLua() {

  Long res = goodsService.flashSellByRedisWatch("xiaomi", 1);
  System.out.println(res.toString());
  return res;
 }