详解Spring Boot使用redis实现数据缓存

2019-11-26 12:35:31

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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;@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);  }}

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;@Mapperpublic 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")@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。

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;@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);  }}

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")@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。

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