在项目中通过Jedis从而实现缓存

我会带着你远行 2022-05-28 00:48 113阅读 0赞

# 在项目中通过Jedis从而实现缓存 #

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本系列博客有  
（1）Linux(Ubuntu16.04)下redis的安装，helloworld及读懂配置文件  
[https://blog.csdn.net/qq\_36521579/article/details/79685097][https_blog.csdn.net_qq_36521579_article_details_79685097]  
（2）Redis集群环境  
[https://blog.csdn.net/qq\_36521579/article/details/79687987][https_blog.csdn.net_qq_36521579_article_details_79687987]

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首先，示例工程是ssm框架+redis+maven，在pom.xml中提供下列依赖  
![这里写图片描述][70]  
若不是maven工程就手动导入jar包  
然后，写一个测试方法  
![这里写图片描述][70 1]  
为减少资源浪费，我们可以使用Jedis连接池  
![这里写图片描述][70 2]  
接下来我们为了能够方便地在业务逻辑中使用Jedis来缓存，写类来调用Jedis  
为了能够在集群版和单机版之间转换，我们先定义一个借口

public interface JedisClient {
        String get(String key);
        String set(String key, String value);
        String hget(String hkey, String key);
        long hset(String hkey, String key, String value);
        long incr(String key);
        long expire(String key, int second);
        long ttl(String key);
        long del(String key);
        long hdel(String hkey, String key); 
    }

单机版实现类

public class JedisClientSingle implements JedisClient{ 
        @Autowired
        private JedisPool jedisPool; 
    
        @Override
        public String get(String key) {
            Jedis jedis = jedisPool.getResource();
            String string = jedis.get(key);
            jedis.close();
            return string;
        }
    
        @Override
        public String set(String key, String value) {
            Jedis jedis = jedisPool.getResource();
            String string = jedis.set(key, value);
            jedis.close();
            return string;
        }
    
        @Override
        public String hget(String hkey, String key) {
            Jedis jedis = jedisPool.getResource();
            String string = jedis.hget(hkey, key);
            jedis.close();
            return string;
        }
    
        @Override
        public long hset(String hkey, String key, String value) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.hset(hkey, key, value);
            jedis.close();
            return result;
        }
    
        @Override
        public long incr(String key) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.incr(key);
            jedis.close();
            return result;
        }
    
        @Override
        public long expire(String key, int second) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.expire(key, second);
            jedis.close();
            return result;
        }
    
        @Override
        public long ttl(String key) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.ttl(key);
            jedis.close();
            return result;
        }
    
        @Override
        public long del(String key) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.del(key);
            jedis.close();
            return result;
        }
    
        @Override
        public long hdel(String hkey, String key) {
            Jedis jedis = jedisPool.getResource();
            Long result = jedis.hdel(hkey, key);
            jedis.close();
            return result;
        }
    }

集群版实现类

public class JedisClientCluster implements JedisClient { 
    
        @Autowired
        private JedisCluster jedisCluster;
    
        @Override
        public String get(String key) {
            return jedisCluster.get(key);
        }
    
        @Override
        public String set(String key, String value) {
            return jedisCluster.set(key, value);
        }
    
        @Override
        public String hget(String hkey, String key) {
            return jedisCluster.hget(hkey, key);
        }
    
        @Override
        public long hset(String hkey, String key, String value) {
            return jedisCluster.hset(hkey, key, value);
        }
    
        @Override
        public long incr(String key) {
            return jedisCluster.incr(key);
        }
    
        @Override
        public long expire(String key, int second) {
            return jedisCluster.expire(key, second);
        }
    
        @Override
        public long ttl(String key) {
            return jedisCluster.ttl(key);
        }
    
        @Override
        public long del(String key) {
    
            return jedisCluster.del(key);
        }
    
        @Override
        public long hdel(String hkey, String key) {
    
            return jedisCluster.hdel(hkey, key);
        }
    }

然后在spring配置文件中配置这两个bean

#### 接下来开始正式工作——把缓存添加到业务逻辑中 ####

注意：缓存的添加不能影响正常的业务逻辑。

@Override
        public List<TbContent> getContentList(long contentCid) {
            //从缓存中取内容
            try {
                String result = jedisClient.hget(INDEX_CONTENT_REDIS_KEY, contentCid + "");
                if (!StringUtils.isBlank(result)) {
                    //把字符串转换成list
                    List<TbContent> resultList = JsonUtils.jsonToList(result, TbContent.class);
                    return resultList;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            //根据内容分类id查询内容列表
            TbContentExample example = new TbContentExample();
            Criteria criteria = example.createCriteria();
            criteria.andCategoryIdEqualTo(contentCid);
            //执行查询
            List<TbContent> list = contentMapper.selectByExample(example);
            //向缓存中添加内容
            try {
                //把list转换成字符串
                String cacheString = JsonUtils.objectToJson(list);
                jedisClient.hset(INDEX_CONTENT_REDIS_KEY, contentCid + "", cacheString);
            } catch (Exception e) {
                e.printStackTrace();
            }
    
            return list;
        }

[https_blog.csdn.net_qq_36521579_article_details_79685097]: https://blog.csdn.net/qq_36521579/article/details/79685097
[https_blog.csdn.net_qq_36521579_article_details_79687987]: https://blog.csdn.net/qq_36521579/article/details/79687987
[70]: /images/20220528/5abfa4f026d9447faf2fca7c88d7e8f2.png
[70 1]: /images/20220528/f6c3aeb94ba34ee481d3010382b9ed1e.png
[70 2]: /images/20220528/dd106f81f5ae4c519626f5fe343e9c2a.png