Spring Boot 2.X：MyBatis 多数据源配置

Posted 2021-03-26

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前言

MyBatis 多数据源配置，最近在项目建设中，需要在原有系统上扩展一个新的业务模块，特意将数据库分库，以便减少复杂度。本文直接以简单的代码示例，如何对 MyBatis 多数据源配置。

准备

创建数据库
db_test

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for t_user
-- ----------------------------
DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user` (
  `id` int(8) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `user_name` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户姓名',
  `user_sex` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户性别',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=23 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of t_user
-- ----------------------------
BEGIN;
INSERT INTO `t_user` VALUES (1, '刘备', '男');
INSERT INTO `t_user` VALUES (2, '孙尚香', '女');
INSERT INTO `t_user` VALUES (3, '周瑜', '男');
INSERT INTO `t_user` VALUES (4, '小乔', '女');
INSERT INTO `t_user` VALUES (5, '诸葛亮', '男');
INSERT INTO `t_user` VALUES (6, '黄月英', '女');
INSERT INTO `t_user` VALUES (7, '关羽', '男');
INSERT INTO `t_user` VALUES (8, '张飞', '男');
INSERT INTO `t_user` VALUES (9, '赵云', '男');
INSERT INTO `t_user` VALUES (10, '黄总', '男');
INSERT INTO `t_user` VALUES (11, '曹操', '男');
INSERT INTO `t_user` VALUES (12, '司马懿', '男');
INSERT INTO `t_user` VALUES (13, '貂蝉', '女');
INSERT INTO `t_user` VALUES (14, '吕布', '男');
INSERT INTO `t_user` VALUES (15, '马超', '男');
INSERT INTO `t_user` VALUES (16, '魏延', '男');
INSERT INTO `t_user` VALUES (17, '孟获', '男');
INSERT INTO `t_user` VALUES (18, '大乔', '女');
INSERT INTO `t_user` VALUES (19, '刘婵', '男');
INSERT INTO `t_user` VALUES (20, '姜维', '男');
INSERT INTO `t_user` VALUES (21, '廖化', '男');
INSERT INTO `t_user` VALUES (22, '关平', '男');
COMMIT;
SET FOREIGN_KEY_CHECKS = 1;

dbb_test2


SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for t_hero
-- ----------------------------
DROP TABLE IF EXISTS `t_hero`;
CREATE TABLE `t_hero` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `hero_code` varchar(32) DEFAULT NULL COMMENT '英雄编码',
  `hero_name` varchar(20) DEFAULT NULL COMMENT '英雄名称',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of t_hero
-- ----------------------------
BEGIN;
INSERT INTO `t_hero` VALUES (1, '001', '德玛西亚');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

构建项目，项目目录结构
技术图片

pom 文件

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.zwqh</groupId>
    <artifactId>spring-boot-mybatis-mulidatasource</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-mybatis-mulidatasource</name>
    <description>spring-boot-mybatis-mulidatasource</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        
        <!-- 热部署模块 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional> <!-- 这个需要为 true 热部署才有效 -->
        </dependency>
                
        <!-- mysql 数据库驱动. -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        
        <!-- mybaits -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>
        
        <!-- alibaba的druid数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.20</version>
        </dependency>
        
        <!-- pagehelper -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.12</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

这里使用了alibaba的druid数据库连接池，Druid 能够提供强大的监控和扩展功能。这里我们暂时只做简单的应用。

配置文件

#master 数据源配置
master.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
master.datasource.url=jdbc:mysql://127.0.0.1:3306/db_test?useUnicode=true&characterEncoding=UTF-8&useSSL=true
master.datasource.username=root
master.datasource.password=zwqh@0258
#slave 数据源配置
slave.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
slave.datasource.url=jdbc:mysql://127.0.0.1:3306/db_test2?useUnicode=true&characterEncoding=UTF-8&useSSL=true
slave.datasource.username=root
slave.datasource.password=zwqh@0258
#mybatis
mybatis.mapper-locations=classpath:/mapper/**/*Mapper.xml

数据源配置

MasterDataSourceConfig 对应数据库 db_test

@Configuration
@MapperScan(basePackages = "cn.zwqh.springboot.dao.master", sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterDataSourceConfig {
    @Value("${master.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${master.datasource.url}")
    private String url;

    @Value("${master.datasource.username}")
    private String username;

    @Value("${master.datasource.password}")
    private String password;

    @Bean(name = "masterDataSource")
    @Primary
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "masterSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/master/*Mapper.xml"));
        return bean.getObject();
    }

    @Bean(name = "masterTransactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("masterDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "masterSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(
            @Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

SlaveDataSourceConfig 对应数据库 db_test2

@Configuration
@MapperScan(basePackages = "cn.zwqh.springboot.dao.slave", sqlSessionFactoryRef = "slaveSqlSessionFactory")
public class SlaveDataSourceConfig {
    @Value("${slave.datasource.driver-class-name}")
    private String driverClassName;

    @Value("${slave.datasource.url}")
    private String url;

    @Value("${slave.datasource.username}")
    private String username;

    @Value("${slave.datasource.password}")
    private String password;

    @Bean(name = "slaveDataSource")
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(@Qualifier("slaveDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
                new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/slave/*Mapper.xml"));
        return bean.getObject();
    }

    @Bean(name = "slaveTransactionManager")
    public DataSourceTransactionManager transactionManager(@Qualifier("slaveDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "slaveSqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(
            @Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

多个数据源在使用的过程中必须指定主库，不然会报错。
@MapperScan(basePackages = "cn.zwqh.springboot.dao.slave") 指定对应 Dao 层的扫描路径。

dao 层和 xml 层

db_test 数据库的 dao 层在 cn.zwqh.springboot.dao.master 包下，db_test2 数据库的 dao 层在 cn.zwqh.springboot.dao.slave 包下。

UserDao

public interface UserDao {

    List<UserEntity> getAll();

}

HeroDao

public interface HeroDao {

    List<Hero> getAllHero();

}

db_test 数据库的 xml 层在 /mapper/master/ 文件路径下，db_test2 数据库的 xml 层在 /mapper/slave/ 文件路径下。

UserMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" 
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.zwqh.springboot.dao.master.UserDao">
    <resultMap type="cn.zwqh.springboot.model.UserEntity" id="user">
        <id property="id" column="id"/>
        <result property="userName" column="user_name"/>
        <result property="userSex" column="user_sex"/>
    </resultMap>
    <!-- 获取所有用户 -->
    <select id="getAll" resultMap="user">
        select * from t_user
    </select>
</mapper>

HeroMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" 
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.zwqh.springboot.dao.slave.HeroDao">
    <resultMap type="cn.zwqh.springboot.model.Hero" id="hero">
        <id property="id" column="id"/>
        <result property="heroCode" column="hero_code"/>
        <result property="heroName" column="hero_name"/>
    </resultMap>
    <!-- 获取所有用户 -->
    <select id="getAllHero" resultMap="hero">
        select * from t_hero
    </select>
</mapper>

测试

测试可以使用 SpringBootTest,也可以放到 Controller中，个人习惯用 Controller。

@RestController
@RequestMapping("/test")
public class TestController {
    
    @Autowired
    private UserDao userDao;
    @Autowired
    private HeroDao heroDao;
    
    /**
     *  查找所有用户
     * @return
     */
    @RequestMapping("/getAllUser")
    public List<UserEntity> getAllUser(){
        return userDao.getAll(); 
    }
    /**
     *  查找所有英雄
     * @return
     */
    @RequestMapping("/getAllHero")
    public List<Hero> getAllHero(){
        return heroDao.getAllHero();
    }
    
}

浏览器直接访问：http://127.0.0.1:8080/test/ 加上相关测试路径即可。

总结

多数据源一般用于主从模式或者按业务分库。

示例代码

github
码云

非特殊说明，本文版权归朝雾轻寒所有，转载请注明出处.

原文标题：Spring Boot 2.X(五)：MyBatis 多数据源配置

原文地址：https://www.zwqh.top/article/info/12

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