Springboot集成mybatis实现多数据源配置详细教程

在实际项目开发过程中,时不时会遇到多数据源的情况,本文详细介绍下Spring Boot集成Mybatis实现多数据源支持。

新建springboot工程，引入web、mysql、mybatis依赖

        <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
         <dependency>
             <groupId>org.mybatis.spring.boot</groupId>
             <artifactId>mybatis-spring-boot-starter</artifactId>
             <version>2.2.2</version>
         </dependency>
         <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
             <scope>runtime</scope>
         </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <optional>true</optional>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.12</version>
             <scope>test</scope>
         </dependency>

在application.properties中配置多数据源

spring.datasource.primary.jdbc-url=jdbc:mysql://localhost:3306/ds0
spring.datasource.primary.username=root
spring.datasource.primary.password=root
spring.datasource.primary.driver-class-name=com.mysql.cj.jdbc.Driver

spring.datasource.secondary.jdbc-url=jdbc:mysql://localhost:3306/ds1
spring.datasource.secondary.username=root
spring.datasource.secondary.password=root
spring.datasource.secondary.driver-class-name=com.mysql.cj.jdbc.Driver

多数据源配置与单个数据源配置不同点在于，spring.datasource之后多了一个数据源名称primary/secondary用来区分不同的数据源;

初始化数据源

新建一个配置类，用来加载多个数据源完成初始化。

@Configuration
public class DataSourceConfiguration {
     @Primary
     @Bean
     @ConfigurationProperties(prefix = "spring.datasource.primary")
     public DataSource primaryDataSource() {
         return DataSourceBuilder.create().build();
     }
     @Bean
     @ConfigurationProperties(prefix = "spring.datasource.secondary")
     public DataSource secondaryDataSource() {
         return DataSourceBuilder.create().build();
     }
}

通过@ConfigurationProperties就可以知道这两个数据源分别加载了spring.datasource.primary.*和spring.datasource.secondary.*的配置。@Primary注解指定了主数据源，当不指定数据源时，就会使用该主数据源。

mybatis配置

@Configuration
@MapperScan(
         basePackages = "com*.primary",
         sqlSessionFactoryRef = "sqlSessionFactoryPrimary",
         sqlSessionTemplateRef = "sqlSessionTemplatePrimary")
public class PrimaryConfig {
     private DataSource primaryDataSource;
     public PrimaryConfig(@Qualifier("primaryDataSource") DataSource primaryDataSource) {
         this.primaryDataSource = primaryDataSource;
     }
     @Bean
     public SqlSessionFactory sqlSessionFactoryPrimary() throws Exception {
         SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
         bean.setDataSource(primaryDataSource);
         return bean.getObject();
     }
     @Bean
     public SqlSessionTemplate sqlSessionTemplatePrimary() throws Exception {
         return new SqlSessionTemplate(sqlSessionFactoryPrimary());
     }
}

@Configuration
@MapperScan(
         basePackages = "com.*.secondary",
         sqlSessionFactoryRef = "sqlSessionFactorySecondary",
         sqlSessionTemplateRef = "sqlSessionTemplateSecondary")
public class SecondaryConfig {
     private DataSource secondaryDataSource;
     public SecondaryConfig(@Qualifier("secondaryDataSource") DataSource secondaryDataSource) {
         this.secondaryDataSource = secondaryDataSource;
     }
     @Bean
     public SqlSessionFactory sqlSessionFactorySecondary() throws Exception {
         SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
         bean.setDataSource(secondaryDataSource);
         return bean.getObject();
     }
     @Bean
     public SqlSessionTemplate sqlSessionTemplateSecondary() throws Exception {
         return new SqlSessionTemplate(sqlSessionFactorySecondary());
     }
}

配置类上使用@MapperScan注解来指定当前数据源下定义的实体和mapper的包路径，还注入了sqlSessionFactory和sqlSessionTemplate，通过@Qualifier注解指定了对应的数据源，其名字对应在DataSourceConfiguration配置类中的数据源定义的函数名。

各个对数据源对应路径下的实体和mapper

@Data
@NoArgsConstructor
public class UserPrimary {
     private Long id;
     private String user_name;
     private Integer age;
     public UserPrimary(String name, Integer age) {
         this.user_name = name;
         this.age = age;
     }
}
public interface UserMapperPrimary {
     @Select("SELECT * FROM USER_0 WHERE USER_NAME = #{name}")
     UserPrimary findByName(@Param("name") String name);
     @Insert("INSERT INTO USER_0 (USER_NAME, AGE) VALUES(#{name}, #{age})")
     int insert(@Param("name") String name, @Param("age") Integer age);
     @Delete("DELETE FROM USER_0")
     int deleteAll();
}

@Data
@NoArgsConstructor
public class UserSecondary {
     private Long id;
     private String user_name;
     private Integer age;
     public UserSecondary(String name, Integer age) {
         this.user_name = name;
         this.age = age;
     }
}
public interface UserMapperSecondary {
     @Select("SELECT * FROM USER_1 WHERE USER_NAME = #{name}")
     UserSecondary findByName(@Param("name") String name);
     @Insert("INSERT INTO USER_1 (USER_NAME, AGE) VALUES(#{name}, #{age})")
     int insert(@Param("name") String name, @Param("age") Integer age);
     @Delete("DELETE FROM USER_1")
     int deleteAll();
}

测试

  @Test
     public void test() {
         // 往Primary数据源插入一条数据
         userMapperPrimary.insert("caocao", 20);
         // 从Primary数据源查询刚才插入的数据，配置正确就可以查询到
         UserPrimary userPrimary = userMapperPrimary.findByName("caocao");
         Assert.assertEquals(20, userPrimary.getAge().intValue());
         // 从Secondary数据源查询刚才插入的数据，配置正确应该是查询不到的
         UserSecondary userSecondary = userMapperSecondary.findByName("caocao");
         Assert.assertNull(userSecondary);
         // 往Secondary数据源插入一条数据
         userMapperSecondary.insert("sunquan", 21);
         // 从Primary数据源查询刚才插入的数据，配置正确应该是查询不到的
         userPrimary = userMapperPrimary.findByName("sunquan");
         Assert.assertNull(userPrimary);
         // 从Secondary数据源查询刚才插入的数据，配置正确就可以查询到
         userSecondary = userMapperSecondary.findByName("sunquan");
         Assert.assertEquals(21, userSecondary.getAge().intValue());
     }