Spring Boot使用redis实现数据缓存

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基于Spring Boot 1.5.2.RELEASE版本，一方面验证与Redis的集成方法，另外了解使用方法。

集成方法

配置依赖

修改pom.xml，增加如下内容。

    <dependency>          <groupId>org.springframework.boot</groupId>          <artifactId>spring-boot-starter-data-redis</artifactId>      </dependency>

配置Redis

修改application.yml，增加如下内容。

spring:    redis:        host: localhost          port: 6379        pool:            max-idle: 8              min-idle: 0            max-active: 8            max-wait: -1

配置Redis缓存

package net.jackieathome.cache;import java.lang.reflect.Method;import org.springframework.cache.CacheManager;import org.springframework.cache.annotation.CachingConfigurerSupport;import org.springframework.cache.annotation.EnableCaching;import org.springframework.cache.interceptor.KeyGenerator;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.redis.cache.RedisCacheManager;import org.springframework.data.redis.connection.RedisConnectionFactory;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.core.StringRedisTemplate;import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;import com.fasterxml.jackson.annotation.JsonAutoDetect;import com.fasterxml.jackson.annotation.PropertyAccessor;import com.fasterxml.jackson.databind.ObjectMapper;@Configuration@EnableCaching // 启用缓存特性public class RedisConfig extends CachingConfigurerSupport {    // 缓存数据时Key的生成器，可以依据业务和技术场景自行定制//  @Bean//  public KeyGenerator customizedKeyGenerator() {//      return new KeyGenerator() {//          @Override//          public Object generate(Object target, Method method, Object... params) {//              StringBuilder sb = new StringBuilder();//              sb.append(target.getClass().getName());//              sb.append(method.getName());//              for (Object obj : params) {//                  sb.append(obj.toString());//              }//              return sb.toString();//          }//      };////  }    // 定制缓存管理器的属性，默认提供的CacheManager对象可能不能满足需要    // 因此建议依赖业务和技术上的需求，自行做一些扩展和定制    @Bean    public CacheManager cacheManager(@SuppressWarnings("rawtypes") RedisTemplate redisTemplate) {        RedisCacheManager redisCacheManager = new RedisCacheManager(redisTemplate);        redisCacheManager.setDefaultExpiration(300);        return redisCacheManager;    }    @Bean    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {        StringRedisTemplate template = new StringRedisTemplate(factory);        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);        ObjectMapper om = new ObjectMapper();        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);        jackson2JsonRedisSerializer.setObjectMapper(om);        template.setValueSerializer(jackson2JsonRedisSerializer);        template.afterPropertiesSet();        return template;    }}

验证集成后的效果

考虑到未来参与的项目基于MyBatis实现数据库访问，而利用缓存，可有效改善Web页面的交互体验，因此设计了如下两个验证方案。

方案一

在访问数据库的数据对象上增加缓存注解，定义缓存策略。从测试效果看，缓存有效。

页面控制器

package net.jackieathome.controller;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;import net.jackieathome.bean.User;import net.jackieathome.dao.UserDao;import net.jackieathome.db.mapper.UserMapper;@RestControllerpublic class UserController {    @Autowired    private UserDao userDao;    @RequestMapping(method = RequestMethod.GET, value = "/user/id/{id}")    public User findUserById(@PathVariable("id") String id) {        return userDao.findUserById(id);    }    @RequestMapping(method = RequestMethod.GET, value = "/user/create")    public User createUser() {        long time = System.currentTimeMillis() / 1000;        String id = "id" + time;        User user = new User();        user.setId(id);        userDao.createUser(user);        return userDao.findUserById(id);    }}

Mapper定义

package net.jackieathome.db.mapper;import java.util.List;import org.apache.ibatis.annotations.Mapper;import org.apache.ibatis.annotations.Param;import org.springframework.cache.annotation.CacheConfig;import org.springframework.cache.annotation.CachePut;import org.springframework.cache.annotation.Cacheable;import net.jackieathome.bean.User;@Mapperpublic interface UserMapper {    void createUser(User user);    User findUserById(@Param("id") String id);}

数据访问对象

package net.jackieathome.dao;import java.util.ArrayList;import java.util.List;import org.apache.ibatis.annotations.Param;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cache.annotation.CacheConfig;import org.springframework.cache.annotation.CachePut;import org.springframework.cache.annotation.Cacheable;import org.springframework.stereotype.Component;import org.springframework.transaction.annotation.Transactional;import net.jackieathome.bean.User;import net.jackieathome.db.mapper.UserMapper;@Component@CacheConfig(cacheNames = "users")@Transactionalpublic class UserDao {    private static final Logger LOG = LoggerFactory.getLogger(UserDao.class);    @Autowired    private UserMapper userMapper;    @CachePut(key = "#p0.id")    public void createUser(User user) {        userMapper.createUser(user);        LOG.debug("create user=" + user);    }    @Cacheable(key = "#p0")    public User findUserById(@Param("id") String id) {        LOG.debug("find user=" + id);        return userMapper.findUserById(id);    }}

方案二

直接在Mapper定义上增加缓存注解，控制缓存策略。从测试效果看，缓存有效，相比于方案一，测试代码更加简洁一些。

页面控制器

package net.jackieathome.controller;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;import net.jackieathome.bean.User;import net.jackieathome.dao.UserDao;import net.jackieathome.db.mapper.UserMapper;@RestControllerpublic class UserController {    @Autowired    private UserMapper userMapper;    @RequestMapping(method = RequestMethod.GET, value = "/user/id/{id}")    public User findUserById(@PathVariable("id") String id) {        return userMapper.findUserById(id);    }    @RequestMapping(method = RequestMethod.GET, value = "/user/create")    public User createUser() {        long time = System.currentTimeMillis() / 1000;        String id = "id" + time;        User user = new User();        user.setId(id);        userMapper.createUser(user);        return userMapper.findUserById(id);    }}

Mapper定义

package net.jackieathome.db.mapper;import java.util.List;import org.apache.ibatis.annotations.Mapper;import org.apache.ibatis.annotations.Param;import org.springframework.cache.annotation.CacheConfig;import org.springframework.cache.annotation.CachePut;import org.springframework.cache.annotation.Cacheable;import net.jackieathome.bean.User;@CacheConfig(cacheNames = "users")@Mapperpublic interface UserMapper {    @CachePut(key = "#p0.id")    void createUser(User user);    @Cacheable(key = "#p0")    User findUserById(@Param("id") String id);}

总结

上述两个测试方案并没有优劣之分，仅是为了验证缓存的使用方法，体现了不同的控制粒度，在实际的项目开发过程中，需要依据实际情况做不同的决断。

缓存相关的注解：

CacheConfig
Cacheable
CachePut
CacheEvict

参考资料

使用redis缓存

Caching
spring-boot/spring-boot-samples/spring-boot-sample-cache
Caching Data in Spring Using Redis
Spring Boot使用redis做数据缓存
Spring-boot用Redis 作为缓存服务
Spring Boot中的缓存支持（二）使用Redis做集中式缓存
Spring Boot使用redis做数据缓存
Spring Boot下配置Redis缓存

MyBatis的缓存特性

MyBatis Ehcache Adapter - Reference Documentation
Mapper XML 文件
mybatis缓存的使用及理解
mybatis缓存
MyBatis 缓存机制深度解剖 / 自定义二级缓存
MyBatis的缓存配置(Cache)
Mybatis二级缓存原理
深入浅出Mybatis-改造Cache
mybatis的缓存机制（一级缓存二级缓存和刷新缓存）和mybatis整合ehcache
《深入理解mybatis原理》 MyBatis缓存机制的设计与实现
《深入理解mybatis原理》 MyBatis的二级缓存的设计原理
mybatis入门基础(八)—–查询缓存

其它

运行redis docker镜像的命令

sudo docker run --rm -d -p 6379:6379 redis

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