详解Spring Boot使用redis实现数据缓存

详解Spring Boot使用redis实现数据缓存

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。

org.springframework.boot

spring-boot-starter-data-redis

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 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 findUserhttp://ById(@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。

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