Redis实现分布式锁

    private static String REDIS_LOCK = "redis_lock";

    @Autowired
    private RedissonClient redission;

 

/**
     * 自定redisLock实现分布式锁，
     * 使用 RedisTemplate + lua脚本实现
     * @return
     */
    @GetMapping("/mylock")
    public String redisLock() {
        String resoult = "";

        long value = System.currentTimeMillis() + Thread.currentThread().getId();
        try {
            //1.原子性的设置锁,并且设置超时时间30s（加分布式锁）
            Boolean flag = redisTemplate.opsForValue().setIfAbsent(REDIS_LOCK, value, 30l, TimeUnit.SECONDS);
            if (!flag) {
                return "抢占锁失败";
            }

            //2.获取库存数量
            Object obj = redisTemplate.opsForValue().get("goods:100");
            int goodsNum = obj == null ? 0 : Integer.parseInt(obj.toString());
            if (goodsNum > 0) {
                goodsNum = goodsNum - 1;
                //3.把库存-1,并且设置会系统中
                redisTemplate.opsForValue().set("goods:100", String.valueOf(goodsNum));

                //模拟超时40秒
                Thread.sleep(40000);

                resoult = "成功购买到商品，剩余库存:" + goodsNum + " 件商品";
            } else {
                resoult = "商品已经售完/活动结束/调用结束，欢迎下次光临";
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            //4.消除分布式锁(使用lua脚本实现删除锁)
            DefaultRedisScript<Long> redisScript = new DefaultRedisScript<>();
            //指定lua脚本
            redisScript.setScriptText("if redis.call(\"get\",KEYS[1]) == ARGV[1] then\n" +
                    "    return redis.call(\"del\",KEYS[1])\n" +
                    "else\n" +
                    "    return 0\n" +
                    "end");
            // 指定返回类型
            redisScript.setResultType(Long.class);
            // 参数一：redisScript，参数二：key列表，参数三：arg（可多个）
            Long result = (Long) redisTemplate.execute(redisScript, Collections.singletonList(REDIS_LOCK), value);
            if (result == 1) {
                System.out.println("删除 锁 ok");
            } else {
                System.out.println("删除 锁 error");
            }
        }

        System.out.println(resoult);
        return resoult;
    }

<dependency>
            <groupId>org.redisson</groupId>
            <artifactId>redisson</artifactId>
            <version>3.15.0</version>
        </dependency>

@Bean
    public RedissonClient redissonClient() {
        Config config = new Config();
        config.setTransportMode(TransportMode.EPOLL);
        config.useClusterServers()
                .addNodeAddress("redis://192.168.2.13:6379");
        return Redisson.create(config);
    }

package com.un.project.system.controller.app;

import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * Redis Lock实现分布式锁
 *
 * @author shiye
 * @create 2021-05-28 13:47
 */
@RestController
@RequestMapping("/ws/redis")
public class MyRedisLockController {


    private static String REDIS_LOCK = "redis_lock";

    @Autowired
    private RedissonClient redission;



    @GetMapping("/redissonlock")
    public String redissonLock() {
        String resoult = "";

        long value = System.currentTimeMillis() + Thread.currentThread().getId();
        //1.使用Redisson来加锁
        RLock redissionLock = redission.getLock(REDIS_LOCK);
        redissionLock.lock(30, TimeUnit.SECONDS);
        try {
            //2.获取库存数量
            Object obj = redisTemplate.opsForValue().get("goods:100");
            int goodsNum = obj == null ? 0 : Integer.parseInt(obj.toString());
            if (goodsNum > 0) {
                goodsNum = goodsNum - 1;
                //3.把库存-1,并且设置会系统中
                redisTemplate.opsForValue().set("goods:100", String.valueOf(goodsNum));

                //模拟超时41秒
                Thread.sleep(41000);

                resoult = "成功购买到商品，剩余库存:" + goodsNum + " 件商品";
            } else {
                resoult = "商品已经售完/活动结束/调用结束，欢迎下次光临";
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            //4.消除分布式锁(使用lua脚本实现删除锁)
            if (redissionLock.isLocked() && redissionLock.isHeldByCurrentThread()) {
                redissionLock.unlock();
            }
        }

        System.out.println(resoult);
        return resoult;
    }

}