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

  1. 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>  
    
  2. 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
    
  3. 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。

  1. 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;
    
    @RestController
    public 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);
        }
    }
    
  2. 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;
    
    
    @Mapper
    public interface UserMapper {
        
        void createUser(User user);
        
        User findUserById(@Param("id") String id);
    }
    
  3. 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")
    @Transactional
    public 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。

  1. 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;
    
    @RestController
    public 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);
        }
    }
    
  2. 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")
    @Mapper
    public 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:

  1. CacheConfig
  2. Cacheable
  3. CachePut
  4. CacheEvict

参考资料

使用redis缓存

MyBatis的缓存特性

其它

  1. 运行redis docker镜像的命令
    sudo docker run --rm -d -p 6379:6379 redis


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