Spring Boot 2.X(五)：MyBatis 多數據源配置

前言

MyBatis 多數據源配置，最近在項目建設中，需要在原有系統上擴展一個新的業務模塊，特意將數據庫分庫，以便減少複雜度。本文直接以簡單的代碼示例，如何對 MyBatis 多數據源配置。

準備

創建數據庫
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 '用戶姓名',
  `user_sex` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用戶性別',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=23 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of t_user
-- ----------------------------
BEGIN;
INSERT INTO `t_user` VALUES (1, '劉備', '男');
INSERT INTO `t_user` VALUES (2, '孫尚香', '女');
INSERT INTO `t_user` VALUES (3, '周瑜', '男');
INSERT INTO `t_user` VALUES (4, '小喬', '女');
INSERT INTO `t_user` VALUES (5, '諸葛亮', '男');
INSERT INTO `t_user` VALUES (6, '黃月英', '女');
INSERT INTO `t_user` VALUES (7, '關羽', '男');
INSERT INTO `t_user` VALUES (8, '張飛', '男');
INSERT INTO `t_user` VALUES (9, '趙雲', '男');
INSERT INTO `t_user` VALUES (10, '黃總', '男');
INSERT INTO `t_user` VALUES (11, '曹操', '男');
INSERT INTO `t_user` VALUES (12, '司馬懿', '男');
INSERT INTO `t_user` VALUES (13, '貂蟬', '女');
INSERT INTO `t_user` VALUES (14, '呂布', '男');
INSERT INTO `t_user` VALUES (15, '馬超', '男');
INSERT INTO `t_user` VALUES (16, '魏延', '男');
INSERT INTO `t_user` VALUES (17, '孟獲', '男');
INSERT INTO `t_user` VALUES (18, '大喬', '女');
INSERT INTO `t_user` VALUES (19, '劉嬋', '男');
INSERT INTO `t_user` VALUES (20, '姜維', '男');
INSERT INTO `t_user` VALUES (21, '廖化', '男');
INSERT INTO `t_user` VALUES (22, '關平', '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 '英雄編碼',
  `hero_name` varchar(20) DEFAULT NULL COMMENT '英雄名稱',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of t_hero
-- ----------------------------
BEGIN;
INSERT INTO `t_hero` VALUES (1, '001', '德瑪西亞');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

構建項目，項目目錄結構

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>
        
        <!-- 熱部署模塊 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional> <!-- 這個需要爲 true 熱部署纔有效 -->
        </dependency>
                
        <!-- mysql 數據庫驅動. -->
        <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數據庫連接池 -->
        <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>

這裏使用了alibaba的druid數據庫連接池，Druid 能夠提供強大的監控和擴展功能。這裏我們暫時只做簡單的應用。

配置文件

#master 數據源配置
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 數據源配置
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

數據源配置

MasterDataSourceConfig 對應數據庫 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 對應數據庫 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);
    }
}

多個數據源在使用的過程中必須指定主庫，不然會報錯。
@MapperScan(basePackages = "cn.zwqh.springboot.dao.slave") 指定對應 Dao 層的掃描路徑。

dao 層和 xml 層

db_test 數據庫的 dao 層在 cn.zwqh.springboot.dao.master 包下，db_test2 數據庫的 dao 層在 cn.zwqh.springboot.dao.slave 包下。

UserDao

public interface UserDao {

    List<UserEntity> getAll();

}

HeroDao

public interface HeroDao {

    List<Hero> getAllHero();

}

db_test 數據庫的 xml 層在 /mapper/master/ 文件路徑下，db_test2 數據庫的 xml 層在 /mapper/slave/ 文件路徑下。

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>
    <!-- 獲取所有用戶 -->
    <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>
    <!-- 獲取所有用戶 -->
    <select id="getAllHero" resultMap="hero">
        select * from t_hero
    </select>
</mapper>

測試

測試可以使用 SpringBootTest,也可以放到 Controller中，個人習慣用 Controller。

@RestController
@RequestMapping("/test")
public class TestController {
    
    @Autowired
    private UserDao userDao;
    @Autowired
    private HeroDao heroDao;
    
    /**
     *  查找所有用戶
     * @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();
    }
    
}

瀏覽器直接訪問：http://127.0.0.1:8080/test/ 加上相關測試路徑即可。

總結

多數據源一般用於主從模式或者按業務分庫。

示例代碼

github
碼雲

非特殊說明，本文版權歸朝霧輕寒所有，轉載請註明出處.

原文標題：Spring Boot 2.X(五)：MyBatis 多數據源配置

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

Spring Boot 2.X(五)：MyBatis 多數據源配置

前言

準備

pom 文件

配置文件

數據源配置

dao 層和 xml 層

測試

總結

示例代碼

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