Spring boot（七）：Spring boot+ mybatis 多数据源最简解决方案

多数据源一般解决哪些问题？主从模式或者业务比较复杂需要连接不同的分库来支持业务。

直接上代码。

配置文件

pom包依赖，该依赖的依赖。主要是数据库这边的配置：

mybatis.config-locations=classpath:mybatis/mybatis-config.xml

spring.datasource.test1.driverClassName = com.mysql.jdbc.Driver
spring.datasource.test1.url = jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8
spring.datasource.test1.username = root
spring.datasource.test1.password = root

spring.datasource.test2.driverClassName = com.mysql.jdbc.Driver
spring.datasource.test2.url = jdbc:mysql://localhost:3306/test2?useUnicode=true&characterEncoding=utf-8
spring.datasource.test2.username = root
spring.datasource.test2.password = root

一个test1和一个test2库，其中test1为主库，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")
    @Primary
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test1SqlSessionFactory")
    @Primary
    public 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")
    @Primary
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

最关键的地方就是这一块了，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。

@MapperScan(basePackages = "com.neo.mapper.test1", sqlSessionTemplateRef  = "test1SqlSessionTemplate")

这块的注解就是指明了扫描的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需要按照库来区分在不同的目录，比如：test1库dao层在com.neo.mapper.test1包下，test2库在com.neo.mapper.test2下

public interface User1Mapper {
	
	List<UserEntity> getAll();
	
	UserEntity getOne(Long id);

	void insert(UserEntity user);

	void update(UserEntity user);

	void delete(Long id);
	
}

xml层

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.neo.mapper.test1.User1Mapper" >			<!--命名空间-->
    <resultMap id="BaseResultMap" type="com.neo.entity.UserEntity" >		<!--结果集-->		
        <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 users
	   WHERE id = #{id}
    </select>

    <insert id="insert" parameterType="com.neo.entity.UserEntity" >
       INSERT INTO 
       		users
       		(userName,passWord,user_sex) 
       	VALUES
       		(#{userName}, #{passWord}, #{userSex})
    </insert>
    
    <update id="update" parameterType="com.neo.entity.UserEntity" >
       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 FROM
       		 users 
       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 {

    @Autowired
    private User1Mapper user1Mapper;

	@Autowired
	private 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);
    }
}

项目地址(码云)