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

﹏ヽ暗。殇╰゛Y 2022-07-14 12:22 188阅读 0赞

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。

> 废话不多说直接上代码吧

## 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); } }

最后源码地址在这里[spring-boot-mybatis-mulidatasource][]

--------------------

[spring-boot-mybatis-mulidatasource]: https://github.com/ityouknow/spring-boot-starter/tree/master/spring-boot-mybatis-mulidatasource
[http_www.ityouknow.com]: http://www.ityouknow.com/springboot/2016/11/25/springboot%28%E4%B8%83%29-springboot+mybatis%E5%A4%9A%E6%95%B0%E6%8D%AE%E6%BA%90%E6%9C%80%E7%AE%80%E8%A7%A3%E5%86%B3%E6%96%B9%E6%A1%88.html