分布式锁实现----Redis+Lua脚本

说明：

每个lua 脚本中的操作都是原子操作

实现步骤

在resources目录下新建 lua 脚本

• /resources/luascript/lock-del.lua

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

• /resources/luascript/lock-set.lua

  --- 获取key
  local key = KEYS[1]
  --- 获取value
  local val = KEYS[2]
  --- 获取一个参数
  local expire = ARGV[1]
  --- 如果redis找不到这个key就去插入
  if redis.call("get", key) == false then
      --- 如果插入成功，就去设置过期值
      if redis.call("set", key, val) then
          --- 由于lua脚本接收到参数都会转为String，所以要转成数字类型才能比较
          if tonumber(expire) > 0 then
              --- 设置过期时间
              redis.call("expire", key, expire)
          end
          return true
      end
      return false
  else
      return false
  end

  Lua 配置类

  @Configuration
  public class LuaConfiguration {
      @Bean(name = "set")
      public DefaultRedisScript<Boolean> redisScript() {
          DefaultRedisScript<Boolean> redisScript = new DefaultRedisScript<>();
          redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("luascript/lock-set.lua")));
          redisScript.setResultType(Boolean.class);
          return redisScript;
      }
  
      @Bean(name = "del")
      public DefaultRedisScript<Boolean> redisScriptDel() {
          DefaultRedisScript<Boolean> redisScript = new DefaultRedisScript<>();
          redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("luascript/lock-del.lua")));
          redisScript.setResultType(Boolean.class);
          return redisScript;
      }
  }

  controller

  @RestController
  public class LuaLockController {
      @Resource(name = "set")
      private DefaultRedisScript<Boolean> redisScript;
      @Resource(name = "del")
      private DefaultRedisScript<Boolean> redisScriptDel;
  
      @Resource
      private StringRedisTemplate stringRedisTemplate;
  
      @GetMapping("/lua")
      public ResponseEntity lua() {
          List<String> keys = Arrays.asList("testLua", "hello lua");
          Boolean execute = stringRedisTemplate.execute(redisScript, keys, "100");
          return null;
      }
  
      @GetMapping("/lua-del")
      public ResponseEntity luaDel() {
          List<String> keys = Arrays.asList("testLua");
          Boolean execute = stringRedisTemplate.execute(redisScriptDel, keys,"hello lua");
          return null;
      }
  }