上一篇我们介绍了mybatis中二级缓存的使用,本篇我们在此基础上介绍Mybatis中如何使用Redis作为二级缓存。
如果您对mybatis中二级缓存的使用不太了解,建议您先进行了解后再阅读本篇,可以参考:
Mybatis 二级缓存https://blog.csdn.net/m1729339749/article/details/133376283
一、添加依赖
<dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.5</version>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.49</version>
</dependency>
<dependency><groupId>org.mybatis.caches</groupId><artifactId>mybatis-redis</artifactId><version>1.0.0-beta2</version>
</dependency>
二、Redis配置
在resources目录下新建redis.properties配置文件
host=localhost
port=6379
connectionTimeout=2000
soTimeout=2000
password=horse
database=0
clientName=Mybatis_Cache
host:redis服务主机
port:redis服务端口
password:redis密码
三、创建实体类
在cn.horse.demo下创建UserInfo、UserInfoQuery类,另外需要特别注意缓存的对象类型必须实现Serializable接口
UserInfo类:
package cn.horse.demo;import java.io.Serializable;public class UserInfo implements Serializable {private static final long serialVersionUID = 9213975268411777481L;private Integer id;private String name;private Integer age;public void setId(Integer id) {this.id = id;}public Integer getId() {return id;}public void setName(String name) {this.name = name;}public String getName() {return name;}public void setAge(Integer age) {this.age = age;}public Integer getAge() {return age;}@Overridepublic String toString() {StringBuilder stringBuilder = new StringBuilder();stringBuilder.append('{');stringBuilder.append("id: " + this.id);stringBuilder.append(", ");stringBuilder.append("name: " + this.name);stringBuilder.append(", ");stringBuilder.append("age: " + this.age);stringBuilder.append('}');return stringBuilder.toString();}
}
UserInfoQuery类:
package cn.horse.demo;public class UserInfoQuery {private Integer startAge;private Integer endAge;public void setStartAge(Integer startAge) {this.startAge = startAge;}public Integer getStartAge() {return startAge;}public void setEndAge(Integer endAge) {this.endAge = endAge;}public Integer getEndAge() {return endAge;}
}
四、创建映射器、Mapper配置
在cn.horse.demo下创建UserInfoMapper接口
UserInfoMapper接口:
package cn.horse.demo;import org.apache.ibatis.annotations.*;import java.util.List;public interface UserInfoMapper {List<UserInfo> find(@Param("query") UserInfoQuery query);
}
在resources下创建cn/horse/demo目录,并在此目录下创建UserInfoMapper.xml配置文件
UserInfoMapper.xml配置:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.horse.demo.UserInfoMapper"><cache type="org.mybatis.caches.redis.RedisCache" /><resultMap id="userInfoMap" type="cn.horse.demo.UserInfo"><result column="ID" property="id" /><result column="USERNAME" property="name"/><result column="AGE" property="age"/></resultMap><select id="find" parameterType="cn.horse.demo.UserInfoQuery" resultMap="userInfoMap">SELECTID,USERNAME,AGEFROM T_USER<where><if test="null != query.startAge">AND AGE >= #{query.startAge}</if><if test="null != query.endAge">AND AGE <= #{query.endAge}</if></where></select>
</mapper>
注意:cache标签代表在此命名空间下使用二级缓存,type代表的是二级缓存的实现方式(这里使用的是org.mybatis.caches.redis.RedisCache)
五、引入配置文件
在resources下新建mybatis-config.xml配置文件,并引入UserInfoMapper映射器。
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><settings><setting name="logImpl" value="JDK_LOGGING"/></settings><environments default="development"><environment id="development"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="org.gjt.mm.mysql.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/demo?useUnicode=true&useSSL=false&characterEncoding=utf8&allowMultiQueries=true"/><property name="username" value="root"/><property name="password" value="horse"/></dataSource></environment></environments><mappers><mapper class="cn.horse.demo.UserInfoMapper" /></mappers>
</configuration>
这里我们使用mapper引入映射器,只需要设置class属性为UserInfoMapper接口的全限类名。
六、启动程序
1、数据准备
这里我们直接使用脚本初始化数据库中的数据
-- 如果数据库不存在则创建数据库
CREATE DATABASE IF NOT EXISTS demo DEFAULT CHARSET utf8;
-- 切换数据库
USE demo;
-- 创建用户表
CREATE TABLE IF NOT EXISTS T_USER(ID INT PRIMARY KEY,USERNAME VARCHAR(32) NOT NULL,AGE INT NOT NULL
);
-- 插入用户数据
INSERT INTO T_USER(ID, USERNAME, AGE)
VALUES(1, '张三', 20),(2, '李四', 22),(3, '王五', 24);
创建了一个名称为demo的数据库;并在库里创建了名称为T_USER的用户表并向表中插入了数据
2、会话工具类
在cn.horse.demo包下新建SqlSessionUtils工具类
package cn.horse.demo;import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.InputStream;
import java.util.Objects;public class SqlSessionUtils {private static final SqlSessionFactory sqlSessionFactory;static {// 读取mybatis配置文件InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("mybatis-config.xml");// 根据配置创建SqlSession工厂sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);}/*** 开启会话* @return*/public static SqlSession openSession() {return sqlSessionFactory.openSession();}/*** 关闭会话* @param sqlSession*/public static void closeSession(SqlSession sqlSession) {if(Objects.nonNull(sqlSession)) {sqlSession.close();}}
}
3、JDK 日志系统配置
在resources的目录下新建logging.properties配置文件
handlers=java.util.logging.ConsoleHandler
.level=INFOcn.horse.demo.level=FINER
java.util.logging.ConsoleHandler.level=ALL
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
java.util.logging.SimpleFormatter.format=%1$tY-%1$tm-%1$td %1$tT.%1$tL %4$s %3$s - %5$s%6$s%n
在cn.horse.demo下创建JdkLogConfig类
JdkLogConfig类:
package cn.horse.demo;import java.io.IOException;
import java.io.InputStream;
import java.util.logging.LogManager;public class JdkLogConfig {public JdkLogConfig() {try {InputStream inputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("logging.properties");LogManager.getLogManager().readConfiguration(inputStream);} catch (IOException e) {throw new RuntimeException(e);}}
}
4、启动程序
package cn.horse.demo;import org.apache.ibatis.session.SqlSession;import java.util.List;
import java.util.function.Consumer;
import java.util.logging.Logger;public class Main {private static final Logger LOGGER;static {// 引入JDK日志配置System.setProperty("java.util.logging.config.class", "cn.horse.demo.JdkLogConfig");LOGGER = Logger.getLogger("cn.horse.demo.Main");}public static void main(String[] args) throws InterruptedException {// 查询selectGreaterThan(20);// 查询selectGreaterThan(20);}private static void selectGreaterThan(Integer age) {LOGGER.finer("--------------- 查询 ----------------");execute((UserInfoMapper userInfoMapper) -> {UserInfoQuery query = new UserInfoQuery();query.setStartAge(age);List<UserInfo> userInfoList = userInfoMapper.find(query);for (UserInfo userInfo: userInfoList) {LOGGER.info(userInfo.toString());}});}private static void execute(Consumer<UserInfoMapper> function) {SqlSession sqlSession = null;try {sqlSession = SqlSessionUtils.openSession();function.accept(sqlSession.getMapper(UserInfoMapper.class));sqlSession.commit();} finally {SqlSessionUtils.closeSession(sqlSession);}}
}
execute方法用于执行操作,方法中使用sqlSession.getMapper方法获取映射器对象,然后将映射器对象具体的执行操作委托给了Consumer对象。
执行后的结果如下: