(十五)SpringBoot之使用Redis做缓存数据
一、添加Redis依赖
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.shyroke.redis</groupId> <artifactId>springboot_redis</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>war</packaging> <name>springboot_redis</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.4.7.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
二、 application配置
server.port=8888 #数据库连接配置 spring.datasource.url=jdbc:mysql://localhost/db_boot?useUnicode=true&characterEncoding=utf-8 spring.datasource.username=root spring.datasource.password= spring.datasource.driver-class-name=com.mysql.jdbc.Driver # JPA spring.jpa.show-sql=true spring.jpa.hibernate.ddl-auto= update #redis spring.cache.type=redis spring.redis.host=localhost spring.redis.port=6379 #spring.redis.password= #spring.redis.database=0 #spring.redis.pool.max-active=8 #spring.redis.pool.max-idle=8 #spring.redis.pool.max-wait=-1 #spring.redis.pool.min-idle=0 #spring.redis.timeout=0
三、 redis缓存配置类
package com.shyroke.config; import com.fasterxml.jackson.annotation.JsonAutoDetect; import com.fasterxml.jackson.annotation.PropertyAccessor; import com.fasterxml.jackson.databind.ObjectMapper; 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 java.lang.reflect.Method; @Configuration public class RedisConfig extends CachingConfigurerSupport { /* * 定义缓存数据 key 生成策略的bean 包名+类名+方法名+所有参数 */ @Bean public KeyGenerator wiselyKeyGenerator(){ 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(); } }; } /* * 要启用spring缓存支持,需创建一个 CacheManager的 bean,CacheManager 接口有很多实现,这里Redis 的集成,用 * RedisCacheManager这个实现类 Redis 不是应用的共享内存,它只是一个内存服务器,就像 MySql 似的, * 我们需要将应用连接到它并使用某种“语言”进行交互,因此我们还需要一个连接工厂以及一个 Spring 和 Redis 对话要用的 * RedisTemplate, 这些都是 Redis 缓存所必需的配置,把它们都放在自定义的 CachingConfigurerSupport 中 */ @Bean public CacheManager cacheManager(@SuppressWarnings("rawtypes") RedisTemplate redisTemplate) { RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate); // cacheManager.setDefaultExpiration(60);//设置缓存保留时间(seconds) return cacheManager; } // 1.项目启动时此方法先被注册成bean被spring管理,如果没有这个bean,则redis可视化工具中的中文内容(key或者value)都会以二进制存储,不易检查。 @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; } }
四、在springboot启动类中添加缓存支持
@SpringBootApplication @EnableCaching public class SpringbootRedisApplication { public static void main(String[] args) { SpringApplication.run(SpringbootRedisApplication.class, args); } }
五、编写控制类
package com.shyroke.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import com.shyroke.bean.UserBean; import com.shyroke.mapper.UserMapper; import com.shyroke.service.UserServiceI; import com.shyroke.util.DateUtil; @Controller @RequestMapping(value = "/") public class IndexController { @Autowired private UserServiceI userService; @ResponseBody @RequestMapping(value = "/get") public UserBean get() { return userService.getUserById(1); } @ResponseBody @RequestMapping(value="/update") public UserBean update() { UserBean user=userService.getUserById(1); user.setCreateTime(DateUtil.getDataFormat()); user.setUserName("test"); return userService.update(user); } @ResponseBody @RequestMapping(value="/del") public String del() { return userService.del(1); } }
六、Service层接口及其实现
package com.shyroke.service; import com.shyroke.bean.UserBean; public interface UserServiceI { UserBean getUserById(int i); UserBean update(UserBean user); String del(int id); }
- 实现类
package com.shyroke.service.impl; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.cache.annotation.CacheConfig; import org.springframework.cache.annotation.CacheEvict; import org.springframework.cache.annotation.CachePut; import org.springframework.cache.annotation.Cacheable; import org.springframework.stereotype.Service; import com.shyroke.bean.UserBean; import com.shyroke.mapper.UserMapper; import com.shyroke.service.UserServiceI; @Service @CacheConfig(cacheNames="users") public class UserServiceImpl implements UserServiceI { @Autowired private UserMapper userMapper; @Cacheable(key="'userCache'") @Override public UserBean getUserById(int i) { System.out.println("执行这里,说明缓存中读取不到数据,直接读取数据库...."); return userMapper.findOne(i); } @CachePut(key="'userCache'") @Override public UserBean update(UserBean user) { System.out.println("执行这里,更新数据库,更新缓存...."); return userMapper.save(user); } @CacheEvict(key="'userCache'") @Override public String del(int id) { userMapper.delete(id); return "删除成功!!!!"; } }
- 注意:
- @CacheConfig(cacheNames="users") 注解指的是该类中的缓存的名称都是users
-
@CachePut(key=" 'userCache' ")中userCache要加‘’单引号,表示这是一个字符串。
-
@Cacheable能够根据方法的请求参数对其结果进行缓存(缓存的是方法的返回结果),一般用于insert()操作
- @CachePut(key="'userCache'")主要针对方法配置,能够根据方法的请求参数对其结果进行缓存,和 @Cacheable 不同的是,它每次都会触发真实方法的调用,一般用于update()操作
- @CacheEvict(key="'userCache'")主要针对方法配置,能够根据一定的条件对缓存进行清空,一般用于delete()操作
- 本例中的@Cacheable和@CachePut和@CacheEvict的key值必须都是同一个缓存的key,因为这样当update的时候缓存的时候,get方法的得到的才是最新数据,而当删除的时候@CacheEvict,也必须把该key的缓存删除。
七、编写mapper
package com.shyroke.mapper; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.stereotype.Repository; import com.shyroke.bean.UserBean; @Repository public interface UserMapper extends JpaRepository<UserBean,Integer> { }
八、实验结果
- 启动springboot会在数据库中根据bean的定义自动创建一个表数据。插入一条测试数据
- 如下访问http://localhost:8888/get ,获取结果,并生成一个缓存。
- 如下 访问 http://localhost:8888/update ,更新数据,更新缓存,
- 执行上一步更新缓存后,如下我们再访问http://localhost:8888/get,获取的是最新数据,且没有没有发出sql语句说明是从缓存中读取的数据。
- 如下访问http://localhost:8888/del,缓存被清空。
九、总结
要缓存的 Java 对象必须实现 Serializable 接口,因为 Spring 会将对象先序列化再存入 Redis,如果不实现 Serializable 的话将会遇到类似这种错误:nested exception is java.lang.IllegalArgumentException: DefaultSerializer requires a Serializable payload but received an object of type。。。