redis的初步理解和使用

Redis的安装

单个安装

集群安装

ps:具体安装步骤请参考宜立方商城day06

连接redis

Jedis

添加依赖（一般加到服务层）

向业务逻辑中添加缓存

接口封装

常用的操作redis的方法提取出一个接口，分别对应单机版和集群版创建两个实现类。

接口定义：

public interface JedisClient { String set(String key, String value); String get(String key); Boolean exists(String key); Long expire(String key, int seconds); Long ttl(String key); Long incr(String key); Long hset(String key, String field, String value); String hget(String key, String field); Long hdel(String key, String... field); }

单机版实现类

public class JedisClientPool implements JedisClient { @Autowired private JedisPool jedisPool; @Override public String set(String key, String value) { Jedis jedis = jedisPool.getResource(); String result = jedis.set(key, value); jedis.close(); return result; } @Override public String get(String key) { Jedis jedis = jedisPool.getResource(); String result = jedis.get(key); jedis.close(); return result; } @Override public Boolean exists(String key) { Jedis jedis = jedisPool.getResource(); Boolean result = jedis.exists(key); jedis.close(); return result; } @Override public Long expire(String key, int seconds) { Jedis jedis = jedisPool.getResource(); Long result = jedis.expire(key, seconds); 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 incr(String key) { Jedis jedis = jedisPool.getResource(); Long result = jedis.incr(key); jedis.close(); return result; } @Override public Long hset(String key, String field, String value) { Jedis jedis = jedisPool.getResource(); Long result = jedis.hset(key, field, value); jedis.close(); return result; } @Override public String hget(String key, String field) { Jedis jedis = jedisPool.getResource(); String result = jedis.hget(key, field); jedis.close(); return result; } @Override public Long hdel(String key, String... field) { Jedis jedis = jedisPool.getResource(); Long result = jedis.hdel(key, field); jedis.close(); return result; } }

配置applicationContext-redis.xml

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context4.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx4.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util4.2.xsd"> <!-- 配置单机版的连接 --> <bean id="jedisPool" class="redis.clients.jedis.JedisPool"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="6379"></constructor-arg> </bean> <bean id="jedisClientPool" class="cn.e3mall.jedis.JedisClientPool"/> </beans>

集群版的实现

实现类

package cn.e3mall.jedis; import org.springframework.beans.factory.annotation.Autowired; import redis.clients.jedis.JedisCluster; public class JedisClientCluster implements JedisClient { @Autowired private JedisCluster jedisCluster; @Override public String set(String key, String value) { return jedisCluster.set(key, value); } @Override public String get(String key) { return jedisCluster.get(key); } @Override public Boolean exists(String key) { return jedisCluster.exists(key); } @Override public Long expire(String key, int seconds) { return jedisCluster.expire(key, seconds); } @Override public Long ttl(String key) { return jedisCluster.ttl(key); } @Override public Long incr(String key) { return jedisCluster.incr(key); } @Override public Long hset(String key, String field, String value) { return jedisCluster.hset(key, field, value); } @Override public String hget(String key, String field) { return jedisCluster.hget(key, field); } @Override public Long hdel(String key, String... field) { return jedisCluster.hdel(key, field); } }

spring的配置

<!-- 集群版的配置 --> <bean id="jedisCluster" class="redis.clients.jedis.JedisCluster"> <constructor-arg> <set> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7001"></constructor-arg> </bean> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7002"></constructor-arg> </bean> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7003"></constructor-arg> </bean> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7004"></constructor-arg> </bean> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7005"></constructor-arg> </bean> <bean class="redis.clients.jedis.HostAndPort"> <constructor-arg name="host" value="192.168.25.153"></constructor-arg> <constructor-arg name="port" value="7006"></constructor-arg> </bean> </set> </constructor-arg> </bean> <bean id="jedisClientCluster" class="cn.e3mall.jedis.JedisClientCluster"/>

ps:单机版和集群版不能共存，使用单机版时注释集群版的配置。使用集群版，把单机版注释。

添加缓存

功能分析

查询内容列表时添加缓存。（添加缓存不能影响正常的业务逻辑）

1、查询数据库之前先查询缓存。

2、查询到结果，直接响应结果。

3、查询不到，缓存中没有需要查询数据库。

4、把查询结果添加到缓存中。

5、返回结果。

例如：

@Override public List<TbContent> getContentList(long cid) { //查询缓存 try { String json = jedisClient.hget(CONTENT_KEY, cid + ""); //判断json是否为空 if (StringUtils.isNotBlank(json)) { //把json转换成list List<TbContent> list = JsonUtils.jsonToList(json, TbContent.class); return list; } } catch (Exception e) { e.printStackTrace(); } //根据cid查询内容列表 TbContentExample example = new TbContentExample(); //设置查询条件 Criteria criteria = example.createCriteria(); criteria.andCategoryIdEqualTo(cid); //执行查询 List<TbContent> list = contentMapper.selectByExample(example); //向缓存中添加数据 try { jedisClient.hset(CONTENT_KEY, cid + "", JsonUtils.objectToJson(list)); } catch (Exception e) { e.printStackTrace(); } return list; }

缓存同步

对内容进行增删改之后只需要吧对应的缓存删除即可

例如：

@Override public E3Result addContent(TbContent content) { //补全属性 content.setCreated(new Date()); content.setUpdated(new Date()); //插入数据 contentMapper.insert(content); //缓存同步 jedisClient.hdel(CONTENT_KEY, content.getCategoryId().toString()); return E3Result.ok(); }