RedisCallback 是redis 一个回调接口，在 Redis 连接后执行单个命令，返回执行命令后的结果。  如果在使用 RedisCallback 时，需要自动获取 Redis 连接资源，使用完毕后并释放连接资源。

        RedisTemplate 类提供了一个 execute 方法，用于执行 Redis 命令并返回执行命令后的结果。

1.lock类方法封装的方法：

package com.ecarx.check.redis;import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.connection.ReturnType;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.types.Expiration;
import org.springframework.stereotype.Component;import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.concurrent.TimeUnit;/*** 类描述 <p>* Copyright: Copyright © 2021 ECARX Co., Ltd. All Rights Reserved. <p>* Company: xxx科技有限公司<p>** @author qb* @since 2023/8/30 14:34*/
@Slf4j
@Component
public class RedisLock {@Autowiredprivate RedisTemplate redisTemplate;/*** 释放锁脚本，原子操作，lua脚本*/private static final String UNLOCK_LUA;/*** 默认过期时间(30ms)*/private static final long DEFAULT_EXPIRE = 30L;static {StringBuilder sb = new StringBuilder();sb.append("if redis.call(\"get\",KEYS[1]) == ARGV[1] ");sb.append("then ");sb.append("    return redis.call(\"del\",KEYS[1]) ");sb.append("else ");sb.append("    return 0 ");sb.append("end ");UNLOCK_LUA = sb.toString();}/*** 获取分布式锁，原子操作* @param lockKey   锁* @param lockValue 唯一ID, 可以使用UUID.randomUUID().toString();* @return 是否枷锁成功*/public boolean lock(String lockKey, String lockValue) {return this.lock(lockKey, lockValue, DEFAULT_EXPIRE, TimeUnit.MILLISECONDS);}/*** 获取分布式锁，原子操作* @param lockKey   锁* @param lockValue 唯一ID, 可以使用UUID.randomUUID().toString();* @param expire    过期时间* @param timeUnit  时间单位* @return 是否枷锁成功*/public boolean lock(String lockKey, String lockValue, long expire, TimeUnit timeUnit) {try {RedisCallback callback = (connection) -> connection.set(lockKey.getBytes(StandardCharsets.UTF_8),lockValue.getBytes(StandardCharsets.UTF_8), Expiration.seconds(timeUnit.toSeconds(expire)),RedisStringCommands.SetOption.SET_IF_ABSENT);return (boolean) redisTemplate.execute(callback);} catch (Exception e) {log.error("redis lock error ,lock key: {}, value : {}, error info : {}", lockKey, lockValue, e);}return false;}/*** 释放锁* @param lockKey   锁* @param lockValue 唯一ID* @return 执行结果*/public boolean unlock(String lockKey, String lockValue) {RedisCallback callback = (connection) -> connection.eval(UNLOCK_LUA.getBytes(), ReturnType.BOOLEAN, 1, lockKey.getBytes(StandardCharsets.UTF_8), lockValue.getBytes(StandardCharsets.UTF_8));return (boolean) redisTemplate.execute(callback);}/*** 获取Redis锁的value值* @param lockKey 锁*/public String get(String lockKey) {try {RedisCallback callback = (connection) -> new String(Objects.requireNonNull(connection.get(lockKey.getBytes())), StandardCharsets.UTF_8);return (String) redisTemplate.execute(callback);} catch (Exception e) {log.error("get redis value occurred an exception,the key is {}, error is {}", lockKey, e);}return null;}/*** 判断key是否存在* @param key 键* @return true 存在 false不存在*/public boolean hasKey(String key) {try {return Boolean.TRUE.equals(redisTemplate.hasKey(key));} catch (Exception e) {log.error(e.getMessage(), e);return false;}}
}

2.使用分布式锁

String taskId = "123456";for (int i = 0; i < 20; i++) {boolean check = redisLock.lock("CHECK_MM_FINISH_BATCH_" + taskId, uuid, 60, TimeUnit.SECONDS);if (check) {try {/** 业务逻辑处理*/} finally {// 释放锁redisLock.unlock("CHECK_MDB_FINISH_BATCH_" + taskId, uuid);log.info("释放锁, 服务:taskId:{}", taskId);}break;} else {log.info("更新完成状态抢锁失败, taskId:{}, batchId:{}", taskId, batchId);// 每次循环延迟三秒Thread.sleep(3000);}
}