SpringBoot ( 七 ) ：springboot + mybatis 多数据源最简解决方案

说起多数据源，一般都来解决那些问题呢，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。我们项目是后者的模式，网上找了很多，大都是根据jpa来做多数据源解决方案，要不就是老的spring多数据源解决方案，还有的是利用aop动态切换，感觉有点小复杂，其实我只是想找一个简单的多数据支持而已，折腾了两个小时整理出来，供大家参考。

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-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库和一个test2库，其中test1位主库，在使用的过程中必须制定主库，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块了，一层一层注入,先创建DataSource，在创建SqlSessionFactory在创建事务，最后包装到SqlSessionTemplate中。其中需要制定分库的mapper文件地址，以及分库到层代码。

@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.test1。

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" >

<resultMap id="BaseResultMap" type="com.neo.entity.UserEntity" >

<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);

}

}

示例代码：

https://github.com/ityouknow/spring-boot-examples