php基于redis的分布式锁实例详解

set cache_key random_seed NX PX 30000

setnx cache_key random_seed 
expire cache_key 30

if redis.call("get",KEYS[1]) == ARGV[1] then
  return redis.call("del",KEYS[1])
else
  return 0
end

public class RedisLockHelper {
  @Resource
  private R2mClusterClient r2mClusterClient;

  /**
   * 类似于setNx的功能，同时设置过期时间为expire毫秒
   *
   * @param key  加锁key
   * @param value 确保在加锁时间内的唯一因子
   * @param expire 过期时间的毫秒数
   * @return
   */
  private String setLock(String key, String value, long expire) {
    return this.set(key, value, "NX", "PX", expire);
  }

  /**
   * 删除指定key value
   * 如果 r2m中 key 对应的value==value  返回 1
   * 如果 r2m中 key 对应的value!=value  返回 0
   *
   * @param key
   * @return
   */
  private boolean atomDelete(String key, String value) {
    List<String> values = new ArrayList<>();
    values.add(value);
    String sb = "if redis.call('get',KEYS[1])==ARGV[1] then " +
        " return redis.call('del',KEYS[1]) " +
        " else " +
        " return 0" +
        " end";
    if (this.eval(sb, key, values) == 1) {
      return true;
    }
    return false;
  }

  private Long eval(String mobel, String key, List<String> value) {
    return (Long) this.r2mClusterClient.eval(mobel, key, value);
  }

  private String set(String key, String value, String nxxx, String expx, long time) {
    return this.r2mClusterClient.set(key, value, nxxx, expx, time);
  }
}