Redis+Lua实现高并发下抢红包

深碍√TFBOYSˉ_ 2023-02-19 11:22 14阅读 0赞

### Redis+Lua实现高并发下抢红包 ###

*   *  一. 实现业务功能点
     *  二. 抢红包流程示意
     *  三. 代码部分
     *  四.致谢

## 一. 实现业务功能点 ##

1.  将所有红包全部存储到Redis ( 红包池 )
2.  用户抢了多少红包, 记录红包被抢的详情信息;
3.  用户只能抢一次红包, 不能重复抢红包

## 二. 抢红包流程示意 ##

![抢红包流程示意][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU5NDA1Ng_size_16_color_FFFFFF_t_70]

## 三. 代码部分 ##

*  完整代码已上传至github [点击获取][Link 1]
 *  **代码运行环境**  
    redis + lua + jdk1.8 + maven  
    ps: 从Redis 2.6 版本开始，内嵌支持 Lua 环境。通过使用EVAL或EVALSHA命令可以使用 Lua 解释器来执行脚本
 *  **实现代码**
    
    **红包池初始化**

public class GenRedPack {
    
        /**
         * 多线程模拟红包池初始化
         */
        public static void genRedPack(){
            final  JedisUtils jedis = new JedisUtils(Basic.ip, Basic.port, Basic.auth);
            // 发枪器
            final  CountDownLatch latch = new CountDownLatch(Basic.threadCount);
            // 清空所有redis缓存
            jedis.flushall();
            // 每个线程需要初始化多少红包
            int per = Basic.redPackCount/Basic.threadCount;
            for (int i = 0; i < Basic.threadCount; i++) {
                final int page = i;
                new Thread( () -> {
                    latch.countDown();
                    try {
                        latch.await();
                    } catch (InterruptedException e) {
                        e.getStackTrace();
                    }
                    JSONObject object = new JSONObject();
    
                    for (int j = page * per; j < (page+1) * per; j++){
                        object.put("id", "rid_" + j);// 红包id
                        object.put("money", j);
                        jedis.lpush(Basic.redPackPoolKey, object.toJSONString());
                    }
                }).start();
            }
        }
    }

**模拟并发抢红包**

public class GetRedPack {
        /**
         * 多线程模拟用户抢红包
         */
        public static void getRedPack(){
            // 发枪器
            final CountDownLatch latch = new CountDownLatch(Basic.threadCount);
            for (int i = 0; i < Basic.threadCount; i++) {
                new Thread(()->{
                    latch.countDown();
                    try {
                        latch.await();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    final  JedisUtils jedis = new JedisUtils(Basic.ip, Basic.port, Basic.auth);
                    while (true){
                        String userId = UUID.randomUUID().toString();
    
                        Object eval = jedis.eval(Basic.getRedPackScript, 4, Basic.redPackPoolKey, Basic.redPackDetailListKey, Basic.userIdRecordKey, userId);
                        if (eval!=null){
                            System.out.println("用户id:" + userId + " 抢红包详情为" + eval);
                        }else{
                            if (jedis.llen(Basic.redPackPoolKey)==0){
                                break;
                            }
                        }
                    }
                }).start();
            }
        }
    }

常量定义

public interface Basic {
        String ip = "192.168.168.14";
        int port = 6379;
        String auth = "123456";
        int redPackCount = 1000;
    
        int threadCount = 20;
        String redPackPoolKey = "redPackPoolKey"; //LIST类型来模拟红包池子
        String redPackDetailListKey = "redPackDetailListKey";//LIST类型，记录所有用户抢红包的详情
        String userIdRecordKey = "userIdRecordKey";//记录已经抢过红包的用户ID,防止重复抢
    
        /*
         * KEYS[1]:redPackPool //模拟红包池，用来从红包池抢红包
         * KEYS[2]:redPackDetailList：//记录所有用户抢红包的详情
         * KEYS[3]:userIdRecord//记录所有已经抢过红包的用户ID
         * KEYS[4]:userId  //模拟抢红包的用户ID
         */
        String getRedPackScript =
                // 判断是否用户是否已抢过红包 如果已抢过直接返回nil
                "if redis.call('hexists', KEYS[3], KEYS[4]) ~= 0 then \n" +
                        "\t\treturn nil\n" +
                        "else\n" +
                        //从红包池取出一个红包
                        "\tlocal redPack = redis.call('rpop', KEYS[1]);\n" +
                        //判断红包是否为空
                        "\tif redPack then \n" +
                        "\t\tlocal x = cjson.decode(redPack);\n" +
                        "\t\tx['userId'] = KEYS[4];\n" +
                        "\t\tlocal re = cjson.encode(x);\n" +
                        // 记录用户已抢过userIdRecordKey
                        "\t\tredis.call('hset', KEYS[3], KEYS[4], '1');\n" +
                        // 保存用户抢红包详情
                        "\t\tredis.call('lpush', KEYS[2],re);\n" +
                        "\t\treturn re;\n" +
                        "\tend\n" +
                        "end\t\n" +
                        "return nil";
    }

测试类

public class RedPackTest {
        public static void main(String[] args) {
            GenRedPack.genRedPack();//初始化红包
    
            GetRedPack.getRedPack();//从红包池抢红包
        }
    }

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <groupId>com.lilei.project</groupId>
        <artifactId>redis-redpack</artifactId>
        <packaging>war</packaging>
        <version>0.0.1-SNAPSHOT</version>
        <name>redis Maven Webapp</name>
        <dependencies>
            <dependency>
                <groupId>redis.clients</groupId>
                <artifactId>jedis</artifactId>
                <version>2.7.2</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastJson</artifactId>
                <version>1.2.31</version>
            </dependency>
        </dependencies>
        <build>
            <finalName>redis-redpack</finalName>
        </build>
    
    
    </project>

## 四.致谢 ##

**感谢大家阅读这篇文章 如有任何问题 可在评论下留言 笔者会在第一时间回复!!**

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU5NDA1Ng_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200620122853392.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU5NDA1Ng==,size_16,color_FFFFFF,t_70
[Link 1]: https://github.com/developleili/redis-redpack