常用操作

public class RedisTest{
        @Resource
        private StringRedisTemplate stringRedisTemplate;
        public void testRedisList(){
                List<String> skuIds = new ArrayList<>();
                // 往redis中存入整个List<String>
                stringRedisTemplate.opsForList().leftPushAll("gulimall:seckill:sessions:12345", skuIds);
                // 获取redis中所有指定格式的key, * 代表不确定的字符
                Set<String> keys = stringRedisTemplate.keys("gulimall:seckill:sessions:" + "*");
                // 取出redis的list中索引从-100到100的所有值
                List<String> skuIds = stringRedisTemplate.opsForList().range("gulimall:seckill:sessions:12345", -100, 100);
        }    
        public void testRedisHash(){
                // 绑定Redis的Hash，准备Hash操作
                BoundHashOperations<String, String, String> skusOperations = stringRedisTemplate
                        .boundHashOps("gulimall:seckill:skus");
                // 存入数据，k、v都得是String类型
                skusOperations.put(relation.getSkuId().toString(), jsonStr);
                // 从Hash中批量获取多个key的值
                List<String> values = skusOperations.multiGet(skuIds);
        }  
        public void testRedisAbsent(){
                // 尝试在Redis中占位
                Boolean absent = stringRedisTemplate.opsForValue().setIfAbsent("123_456_789", "1000", 145632549L,
                        TimeUnit.MILLISECONDS);
        }          
}

存储获取缓存值

RedisKeyUtil.java

    /*
     * 首页猜你喜欢商品集合
     *
     * @param regionCode
     * @return
     */
    public static String getGuessYouLikeProductsKey(Integer regionCode) {
        return MessageFormat.format("{0}:home:like:product:{1}", PROJECT_SPACE, String.valueOf(regionCode));
    }

RetailHomeServiceImpl.java

    @Resource
    private RedisService redisService;
    private List<Long> getProductIds(List<Long> mchIds, String key) {
        String key = RedisKeyUtil.getGuessYouLikeProductsKey(regionCode);
        String jsonString = redisService.get(key);
        List<Long> productIds;
        if (StringUtils.isNotEmpty(jsonString)) {
            // 缓存不为空，直接取缓存
            productIds = JSON.parseObject(jsonString, new TypeReference<List<Long>>() {
            });
        } else {
            // 缓存为空，则重新查询
            productIds = retailProductService.getRandomProductIds(mchIds);
            // 要缓存的值
            String redisValue = JSON.toJSONString(productIds);
            // 存入redis
            redisService.set(key, redisValue, RetailPortalConstant.ORDER_TIMEOUT_PAY, TimeUnit.MINUTES);
        }
        return productIds;
    }

分布式锁

配置类

@Configuration
public class RedissonConfig {
    /**
     * 所有对Redisson的使用都是通过RedissonClient对象
     * @return
     */
    @Bean(destroyMethod = "shutdown")   // 服务停止以后，会调用shutdown进行销毁
    RedissonClient redission() {
        Config config = new Config();
        config.useSingleServer().setAddress("redis://192.168.2.190:6379");
        return Redisson.create(config);
    }
}

使用

public class RedissonTest{
    @Resource
    private RedissonClient redissonClient;
    public void test1(){
        // 为了限流：使用秒杀商品的库存作为分布式的信号量
        RSemaphore semaphore = redissonClient.getSemaphore("gulimall:seckill:semaphore:11984846");
        // 为信号量设置值
        semaphore.trySetPermits(relation.getSeckillCount());
        // 让信号量尝试扣减值
        try {
            // 要扣的数量，等待的时间，时间单位
            boolean acquire = semaphore.tryAcquire(1, 100, TimeUnit.MILLISECONDS);
            if (acquire) {
                // 扣减成功
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
       }
    }
}