java中采用lua脚本执行redis操作

你的名字 2022-12-29 06:54 309阅读 0赞

如果项目不想使用RedissonClient(不同意引入相关依赖)，则可以用lua脚本去实现，因为lua脚本的执行是原子性的  
1.lua的执行脚本，set数据 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

del数据 lock-del.lua

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

***注：lua脚本执行 都是原子操作***  
lua脚本的java配置

package com.online.taxi.order.config;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.core.io.ClassPathResource;
    import org.springframework.data.redis.core.script.DefaultRedisScript;
    import org.springframework.scripting.support.ResourceScriptSource;
    
    @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;
        }
    }

这样就免去了service层，直接在controller层调用lua脚本就可以

package com.online.taxi.order.controller;
    
    import org.springframework.data.redis.core.StringRedisTemplate;
    import org.springframework.data.redis.core.script.DefaultRedisScript;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    import java.util.Arrays;
    import java.util.List;
    
    
    @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;
        }
    }