Return 从 Lua 脚本设置

Question

Lua 脚本：

local r = {}

for _, m in pairs(ARGV) do
    if redis.call('SISMEMBER', KEYS[1], m) == 1 then
        r[#r + 1] = m
    end
end
return r

我用的是spring boot的redis-template

@Autowired
private RedisScript<Set> redisScript;

Set<String> set = redisTemplete.execute(redisScript,"a", Arrays.asList("1", "2")); --to execute redis lua scipt 

Above redisTemplete.execute command not working error: java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Set

It works when I use assign result to List instead of Set    List<String> set = redisTemplete.execute(redisScript, "a", Arrays.asList("1", "2")); --working

有没有办法修改 Lua 脚本，使其 returns 设置而不是列表？

Answer 1

来自https://docs.spring.io/spring-data/redis/docs/current/api/org/springframework/data/redis/core/script/RedisScript.html

Interface RedisScript<T>

Type Parameters: T - The script result type. Should be one of Long, Boolean, List, or deserialized value type. Can be null if the script returns a throw-away status (i.e "OK")

所以你的 redis 脚本一开始就不应该有 Set 类型。

执行将return那个类型。因此，如果您想要一个 Set，您可能会将 List 转换为 Java 端的 Set。

来自https://redis.io/commands/eval

Note: as you can see Lua arrays are returned as Redis multi bulk replies, that is a Redis return type that your client library will likely convert into an Array type in your programming language.

虽然您可以使用表格在 Lua 中实现集合，但我认为没有办法通过您的 API 获取该集合，因为它将被转换为多批回复，即然后转换为列表。

Return 从 Lua 脚本设置

Return Set from Lua Script

java

lua

redis

spring-boot