springboot+mybatis 用redis作二级缓存
1.加入相关依赖包：
<?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>springBootD</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.3.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>
<!--mybatis依赖--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency>
<!--redis依赖--> <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>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency>
<!--swagger2自动文档依赖--> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger2</artifactId> <version>2.6.1</version> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger-ui</artifactId> <version>2.6.1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin>
<!--生成实体类、mapper映射接口、mapperXML映射文件 插件--> <plugin> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-maven-plugin</artifactId> <version>1.3.2</version> <configuration> <!--配置文件的位置--> <configurationFile>src/main/resources/generatorConfig.xml</configurationFile> <verbose>true</verbose> <overwrite>true</overwrite> </configuration> <executions> <execution> <id>Generate MyBatis Artifacts</id> <goals> <goal>generate</goal> </goals> </execution> </executions> <dependencies> <dependency> <groupId>org.mybatis.generator</groupId> <artifactId>mybatis-generator-core</artifactId> <version>1.3.2</version> </dependency> </dependencies> </plugin> </plugins> </build> </project>
2.springboot配置文件：
#数据库配置 spring.datasource.data-username=com.mysql..jdbc.Driver spring.datasource.url=jdbc:mysql://localhost:3306/springboot?seUnicode=true&characterEncoding=utf8&characterSetResults=utf8 spring.datasource.username=root spring.datasource.password=root #redis配置 spring.redis.host=localhost spring.redis.port=6379 spring.redis.database=1 spring.redis.jedis.pool.max-active=8 spring.redis.jedis.pool.max-wait= -1ms spring.redis.jedis.pool.max-idle=500 #mybatis mybatis.mapper-locations=classpath*:mybatis/mapper/**/*.xml #开启MyBatis的二级缓存 mybatis.configuration.cache-enabled=true #日志配置 logging.level.springbootd.demo=debug logging.level.org.springframework.web=debug logging.level.org.springframework.transaction=debug logging.level.org.mybatis=debug
3.建立获取spring容器获取bean工具类，通过Spring Aware（容器感知）来获取到ApplicationContext，然后根据ApplicationContext获取容器中的Bean，因为RedisTemplate的bean不能用@Autowired注解注入
package springbootd.demo.util; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; import org.springframework.stereotype.Component; @Component public class ApplicationContextHolder implements ApplicationContextAware{ private static ApplicationContext applicationContext; /** * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量. */ public void setApplicationContext(ApplicationContext applicationContext) { ApplicationContextHolder.applicationContext = applicationContext; // NOSONAR } /** * 取得存储在静态变量中的ApplicationContext. */ public static ApplicationContext getApplicationContext() { checkApplicationContext(); return applicationContext; } /** * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. */ @SuppressWarnings("unchecked") public static <T> T getBean(String name) { checkApplicationContext(); return (T) applicationContext.getBean(name); } /** * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型. */ @SuppressWarnings("unchecked") public static <T> T getBean(Class<T> clazz) { checkApplicationContext(); return (T) applicationContext.getBeansOfType(clazz); } /** * 清除applicationContext静态变量. */ public static void cleanApplicationContext() { applicationContext = null; } private static void checkApplicationContext() { if (applicationContext == null) { throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder"); } } }
4.实现mybatis缓存接口：
package springbootd.demo.util; import org.apache.ibatis.cache.Cache; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.data.redis.core.RedisCallback; import org.springframework.data.redis.core.RedisTemplate; import org.springframework.data.redis.core.ValueOperations; import java.util.concurrent.TimeUnit; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; public class MybatisRedisCache implements Cache { private static final Logger logger = LoggerFactory.getLogger(MybatisRedisCache.class); private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock(); private final String id; // cache instance id private RedisTemplate redisTemplate; private static final long EXPIRE_TIME_IN_MINUTES = 30; // redis过期时间 public MybatisRedisCache(String id) { if (id == null) { throw new IllegalArgumentException("Cache instances require an ID"); } this.id = id; } @Override public String getId() { return id; } /** * Put query result to redis * * @param key * @param value */ @Override @SuppressWarnings("unchecked") public void putObject(Object key, Object value) { RedisTemplate redisTemplate = getRedisTemplate(); ValueOperations opsForValue = redisTemplate.opsForValue(); opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES); logger.debug("Put query result to redis"); } /** * Get cached query result from redis * * @param key * @return */ @Override public Object getObject(Object key) { RedisTemplate redisTemplate = getRedisTemplate(); ValueOperations opsForValue = redisTemplate.opsForValue(); logger.debug("Get cached query result from redis"); return opsForValue.get(key); } /** * Remove cached query result from redis * * @param key * @return */ @Override @SuppressWarnings("unchecked") public Object removeObject(Object key) { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.delete(key); logger.debug("Remove cached query result from redis"); return null; } /** * Clears this cache instance */ @Override public void clear() { RedisTemplate redisTemplate = getRedisTemplate(); redisTemplate.execute((RedisCallback) connection -> { connection.flushDb(); return null; }); logger.debug("Clear all the cached query result from redis"); } @Override public int getSize() { return 0; } @Override public ReadWriteLock getReadWriteLock() { return readWriteLock; } private RedisTemplate getRedisTemplate() { if (redisTemplate == null) { redisTemplate = ApplicationContextHolder.getBean("redisTemplate"); } return redisTemplate; } }
5.在mapper.xml映射文件中开启缓存：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="springbootd.demo.mybatisDao.UserMapper" > <cache type="springbootd.demo.util.MybatisRedisCache"/> <resultMap id="BaseResultMap" type="springbootd.demo.mybatisEntity.User" > <id column="id" property="id" jdbcType="BIGINT" /> <result column="pass_word" property="passWord" jdbcType="VARCHAR" /> <result column="user_name" property="userName" jdbcType="VARCHAR" /> </resultMap> <sql id="Base_Column_List" > id, pass_word, user_name </sql> <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long" > select <include refid="Base_Column_List" /> from user where id = #{id,jdbcType=BIGINT} </select> </mapper>
细节提示：
1.mapper映射接口类要加上@mapper注解，将其添加入ioc容器：
import org.apache.ibatis.annotations.Mapper; import springbootd.demo.mybatisEntity.User; @Mapper public interface UserMapper {
User selectByPrimaryKey(Long id); }
或者在springboot入口类加上@MapperScan(basePackages ="包路径")
@SpringBootApplication @MapperScan(basePackages ="springbootd.demo.mybatisDao") public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } }
