springboot之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。

我们以 Mybatis Xml 版本为例，给大家展示如何如何配置多数据源。

目录结构

 使用到的依赖

pom.xml

    
        
            org.springframework.boot
            spring-boot-starter-web
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
            
                
                    org.junit.vintage
                    junit-vintage-engine
                
            
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.0.0
        
        
            mysql
            mysql-connector-java
        
        
            junit
            junit
            test

配置文件

application.properties

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

spring.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.Driver

spring.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 为主库，在使用的过程中必须指定主库，不然会报错。

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
"-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">

    
        "Integer" type="java.lang.Integer" />
        "Long" type="java.lang.Long" />
        "HashMap" type="java.util.HashMap" />
        "LinkedHashMap" type="java.util.LinkedHashMap" />
        "ArrayList" type="java.util.ArrayList" />
        "LinkedList" type="java.util.LinkedList" />

数据源配置

DataSource1Config.java
@Configuration
@MapperScan(basePackages = "com.vincent.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,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。

DataSource2Config.java
@Configuration
@MapperScan(basePackages = "com.vincent.mapper.test2", sqlSessionTemplateRef  = "test2SqlSessionTemplate")
public class DataSource2Config {
    @Bean(name = "test2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test2")
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test2SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test2/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "test2TransactionManager")
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test2SqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

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.vincent.mapper.test1 包下，test2 库在com.vincent.mapper.test2

User1Mapper.java 
public interface User1Mapper {
    List getAll();
    UserEntity getOne(Long id);
    void insert(UserEntity user);
    void update(UserEntity user);
    void delete(Long id);
}
User2Mapper.java
public interface User2Mapper {
    List getAll();

    User getOne(Long id);

    void insert(User user);

    void update(User user);

    void delete(Long id);
}

xml 层

配置文件目录结构

 test1/UserMapper.xml 

<?xml version="1.0" encoding="UTF-8" ?>

com.vincent.mapper.test1.User1Mapper" >
    
        
        
        
        
        
    

    
        id, userName, passWord, user_sex, nick_name
    

    

    

    
       INSERT INTO
               users
               (userName,passWord,user_sex)
           VALUES
               (#{userName}, #{passWord}, #{userSex})
    

    
       UPDATE
               users
       SET
           <if test="userName != null">userName = #{userName},if>
           <if test="passWord != null">passWord = #{passWord},if>
           nick_name = #{nickName}
       WHERE
               id = #{id}
    

    
       DELETE FROM
                users
       WHERE
                id =#{id}

test2/UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>


    
        
        
        
        
        
    

    
        id, userName, passWord, user_sex, nick_name
    

    

    

    
       INSERT INTO
               users
               (userName,passWord,user_sex)
           VALUES
               (#{userName}, #{passWord}, #{userSex})
    

    
       UPDATE
               users
       SET
           <if test="userName != null">userName = #{userName},if>
           <if test="passWord != null">passWord = #{passWord},if>
           nick_name = #{nickName}
       WHERE
               id = #{id}
    

    
       DELETE FROM
                users
       WHERE
                id =#{id}

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 getUsers() {
        List 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);
    }
    
}

Mybatis 注解版本配置多数据源和 Xml 版本基本一致，搭建可以参考文末的示例项目。

参考网址

 代码网址

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