以 Mybatis Xml 版本为例，如何配置多数据源。
配置文件
Pom 包就不贴了比较简单该依赖的就依赖，主要是数据库这边的配置：
mybatis.config-location=classpath:mybatis/mybatis-config.xmlspring.datasource.test1.jdbc-url=jdbc:mysql://localhost:3306/test1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.test1.username=root
spring.datasource.test1.password=root
spring.datasource.test1.driver-class-name=com.mysql.cj.jdbc.Driverspring.datasource.test2.jdbc-url=jdbc:mysql://localhost:3306/test2?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.test2.username=root
spring.datasource.test2.password=root
spring.datasource.test2.driver-class-name=com.mysql.cj.jdbc.Driver
一个 test1 库和一个 test2 库，其中 test1 位主库，在使用的过程中必须指定主库，不然会报错。
数据源配置
@Configuration
@MapperScan(basePackages = "com.neo.mapper.test1", sqlSessionTemplateRef = "test1SqlSessionTemplate")
public class DataSource1Config {@Bean(name = "test1DataSource")@ConfigurationProperties(prefix = "spring.datasource.test1")@Primarypublic DataSource testDataSource() {return DataSourceBuilder.create().build();}@Bean(name = "test1SqlSessionFactory")@Primarypublic SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource) throws Exception {SqlSessionFactoryBean bean = new SqlSessionFactoryBean();bean.setDataSource(dataSource);bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));return bean.getObject();}@Bean(name = "test1TransactionManager")@Primarypublic DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);}@Bean(name = "test1SqlSessionTemplate")@Primarypublic SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {return new SqlSessionTemplate(sqlSessionFactory);}
}
最关键的地方就是这块了，一层一层注入,首先创建 DataSource，然后创建 SqlSessionFactory 再创建事务，最后包装到 SqlSessionTemplate 中。其中需要指定分库的 mapper 文件地址，以及分库dao层代码
@MapperScan(basePackages = "com.neo.mapper.test1", sqlSessionTemplateRef = "test1SqlSessionTemplate")
这块的注解就是指明了扫描 dao 层，并且给 dao 层注入指定的 SqlSessionTemplate。所有@Bean都需要按照命名指定正确。
dao 层和 xml层
dao 层和 xml 需要按照库来分在不同的目录，比如：test1 库 dao 层在 com.neo.mapper.test1 包下，test2 库在com.neo.mapper.test2
public interface User1Mapper {List<UserEntity> getAll();UserEntity getOne(Long id);void insert(UserEntity user);void update(UserEntity user);void delete(Long id);
}
xml 层
<mapper namespace="com.neo.mapper.test1.User1Mapper" ><resultMap id="BaseResultMap" type="com.neo.model.User" ><id column="id" property="id" jdbcType="BIGINT" /><result column="userName" property="userName" jdbcType="VARCHAR" /><result column="passWord" property="passWord" jdbcType="VARCHAR" /><result column="user_sex" property="userSex" javaType="com.neo.enums.UserSexEnum"/><result column="nick_name" property="nickName" jdbcType="VARCHAR" /></resultMap><sql id="Base_Column_List" >id, userName, passWord, user_sex, nick_name</sql><select id="getAll" resultMap="BaseResultMap" >SELECT <include refid="Base_Column_List" />FROM users</select><select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >SELECT <include refid="Base_Column_List" />FROM usersWHERE id = #{id}</select><insert id="insert" parameterType="com.neo.model.User" >INSERT INTO users(userName,passWord,user_sex) VALUES(#{userName}, #{passWord}, #{userSex})</insert><update id="update" parameterType="com.neo.model.User" >UPDATE users SET <if test="userName != null">userName = #{userName},</if><if test="passWord != null">passWord = #{passWord},</if>nick_name = #{nickName}WHERE id = #{id}</update><delete id="delete" parameterType="java.lang.Long" >DELETE FROMusers WHERE id =#{id}</delete></mapper>
测试
测试可以使用 SpringBootTest,也可以放到 Controller中，这里只贴 Controller 层的使用
@RestController
public class UserController {@Autowiredprivate User1Mapper user1Mapper;@Autowiredprivate User2Mapper user2Mapper;@RequestMapping("/getUsers")public List<UserEntity> getUsers() {List<UserEntity> users=user1Mapper.getAll();return users;}@RequestMapping("/getUser")public UserEntity getUser(Long id) {UserEntity user=user2Mapper.getOne(id);return user;}@RequestMapping("/add")public void save(UserEntity user) {user2Mapper.insert(user);}@RequestMapping(value="update")public void update(UserEntity user) {user2Mapper.update(user);}@RequestMapping(value="/delete/{id}")public void delete(@PathVariable("id") Long id) {user1Mapper.delete(id);}}
JAVA 复制 全屏
Mybatis 注解版本配置多数据源和 Xml 版本基本一致。