用Lua脚本实现Redis原子操作的示例

<dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-data-redis</artifactid>
</dependency>

@configuration
public class redisconfig {
    @bean
    public redistemplate<string, object> redistemplate(redisconnectionfactory factory) {
        redistemplate<string, object> template = new redistemplate<>();
        template.setconnectionfactory(factory);
        template.setkeyserializer(new stringredisserializer());
        template.setvalueserializer(new genericjackson2jsonredisserializer());
        return template;
    }
}

local key = keys[1]
local value = argv[1]
local expire = argv[2]
-- 如果key不存在则设置，并添加过期时间
if redis.call('setnx', key, value) == 1 then
    redis.call('expire', key, expire)
    return 1 -- 加锁成功
else
    return 0 -- 加锁失败
end

local key = keys[1]
local value = argv[1]
-- 只有锁的值匹配时才删除
if redis.call('get', key) == value then
    return redis.call('del', key)
else
    return 0
end

@configuration
public class luascriptconfig {
    @bean
    public defaultredisscript<long> lockscript() {
        defaultredisscript<long> script = new defaultredisscript<>();
        script.setlocation(new classpathresource("lock.lua"));
        script.setresulttype(long.class);
        return script;
    }
}

@service
public class redislockservice {
    @autowired
    private redistemplate<string, object> redistemplate;
    @autowired
    private defaultredisscript<long> lockscript;

    public boolean trylock(string key, string value, int expiresec) {
        list<string> keys = collections.singletonlist(key);
        long result = redistemplate.execute(
                lockscript,
                keys,
                value,
                string.valueof(expiresec)
        );
        return result != null && result == 1;
    }
}

// 正确传参示例
list<string> keys = arrays.aslist("key1", "key2"); // keys数组
object[] args = new object[]{"arg1", "arg2"};      // argv数组

string key = "{user}:lock:" + userid; // 所有包含{user}的key分配到同一节点

public boolean trylockwithretry(string key, int maxretry) {
    int retry = 0;
    while (retry < maxretry) {
        if (trylock(key, "value", 30)) {
            return true;
        }
        retry++;
        thread.sleep(100); // 短暂等待
    }
    return false;
}

// 加锁
public boolean lock(string key, string value, int expiresec) {
    return redistemplate.execute(
        lockscript,
        collections.singletonlist(key),
        value,
        string.valueof(expiresec)
    ) == 1;
}

// 解锁
public void unlock(string key, string value) {
    long result = redistemplate.execute(
        unlockscript,
        collections.singletonlist(key),
        value
    );
    if (result == null || result == 0) {
        throw new runtimeexception("解锁失败：锁已过期或非持有者");
    }
}

# 直接在redis服务器测试脚本
eval "return redis.call('setnx', keys[1], argv[1])" 1 mykey 123

# application.properties
logging.level.org.springframework.data.redis=debug

# redis慢查询日志
slowlog-log-slower-than 5
slowlog-max-len 128