若要在Java中使用RedisTemplate实现分布式Redis令牌桶限流,并将Lua脚本存储在单独的文件中,请按照以下步骤进行:

  1. 创建Lua脚本文件(例如:token-bucket.lua),并将其放在资源目录中:

src/main/resources/token-bucket.lua:

local tokensKey = KEYS[1]
local timestampKey = KEYS[2]
local rate = tonumber(ARGV[1])
local capacity = tonumber(ARGV[2])
local now = tonumber(ARGV[3])
local requested = tonumber(ARGV[4])

local lastTokens = tonumber(redis.call('get', tokensKey))
if lastTokens == nil then
  lastTokens = capacity
end

local lastRefreshed = tonumber(redis.call('get', timestampKey))
if lastRefreshed == nil then
  lastRefreshed = now
end

local delta = math.max(0, now - lastRefreshed)
local filledTokens = math.min(capacity, lastTokens + (delta / 1000) * rate)
local allowed = filledTokens >= requested
local newTokens = filledTokens
if allowed then
  newTokens = filledTokens - requested
end

redis.call('set', tokensKey, newTokens)
redis.call('set', timestampKey, now)
o r
redis.call('set', tokensKey, newTokens, 'EX', 60)
redis.call('set', timestampKey, now, 'EX', 60)


return allowed
  1. 在Java中创建一个类,使用RedisTemplate来加载和执行Lua脚本:
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.scripting.support.ResourceScriptSource;

import java.io.Serializable;
import java.util.Collections;
import java.util.List;

public class RedisTokenBucketLimiter {

    private RedisTemplate<String, Serializable> redisTemplate;
    private String key;
    private double refillRate;
    private long capacity;

    public RedisTokenBucketLimiter(RedisTemplate<String, Serializable> redisTemplate, String key, double refillRate, long capacity) {
        this.redisTemplate = redisTemplate;
        this.key = key;
        this.refillRate = refillRate;
        this.capacity = capacity;
    }

    public boolean tryAcquire() {
        String luaScriptPath = "token-bucket.lua";
        Resource scriptSource = new ClassPathResource(luaScriptPath);
        DefaultRedisScript<Long> redisScript = new DefaultRedisScript<>();
        redisScript.setScriptSource(new ResourceScriptSource(scriptSource));
        redisScript.setResultType(Long.class);
        
        List<String> keys = Collections.singletonList(key);
        long now = System.currentTimeMillis();
        Long result = redisTemplate.execute(redisScript, keys, refillRate, capacity, now, 1);
        
        return result != null && result == 1;
    }
}

在这个类中:

  • redisTemplate 是Spring的RedisTemplate实例,它用于与Redis进行交云。
  • key 是Redis中用于标识令牌桶的键。
  • refillRate 是每秒钟向桶中添加的令牌数。
  • capacity 是桶的最大容量。
  • tryAcquire 方法尝试获取一个令牌。如果成功获取,则返回 true;如果获取失败,则返回 false

此代码段中,我们使用ClassPathResource来加载位于类路径下的Lua脚本文件,并通过ResourceScriptSource将其传递给DefaultRedisScript,然后执行Lua脚本。

确保在实际部署时,token-bucket.lua Lua脚本文件位于你的项目资源目录中,以便ClassPathResource能够找到并加载它。

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