Springboot+Mybatis+mysql分包方式配置多数据源

多数据源配置主要是有两种配置方式，一种是分包方式，另一种是通过AOP实现，本篇主要讲通过分包方式来实现多数据源配置。

---

一、添加项目依赖

<!-- mybatis start -->
<dependency>
	<groupId>org.mybatis.spring.boot</groupId>
	<artifactId>mybatis-spring-boot-starter</artifactId>
	<version>1.2.0</version>
</dependency>

<!-- mysql 驱动 -->
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<scope>runtime</scope>
</dependency>

<!-- druid数据库连接池 -->
<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>druid</artifactId>
	<version>1.0.18</version>
</dependency>

<!--mybatis分页插件-->
<dependency>
	<groupId>com.github.pagehelper</groupId>
	<artifactId>pagehelper</artifactId>
	<version>4.1.6</version>
</dependency>

二、编写application配置文件信息

本人使用的是.properties配置文件，yml的自定转换格式，这里以两个库为例，有多少个库就写多少个数据源配置信息。

#执行mapper里的接口后会打印出执行的sql语句
logging.level.com.boot.framework.mapper = debug

spring.datasource.userdb.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.userdb.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.userdb.jdbcUrl = jdbc:mysql://localhost:3306/db_user?useSSL=false&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&serverTimezone=GMT%2B8
spring.datasource.userdb.username = root
spring.datasource.userdb.password = 123456
spring.datasource.userdb.validationQuery=SELECT 1
spring.datasource.userdb.testWhileIdle=true
spring.datasource.userdb.timeBetweenEvictionRunsMillis=300000
spring.datasource.userdb.numTestsPerEvictionRun=50
spring.datasource.userdb.minEvictableIdleTimeMillis=3600000

spring.datasource.admindb.type = com.alibaba.druid.pool.DruidDataSource
spring.datasource.admindb.driver-class-name = com.mysql.cj.jdbc.Driver
spring.datasource.admindb.jdbcUrl = jdbc:mysql://localhost:3306/db_admin?useSSL=false&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&serverTimezone=GMT%2B8
spring.datasource.admindb.username = root
spring.datasource.admindb.password = 123456
spring.datasource.admindb.validationQuery=SELECT 1
spring.datasource.admindb.testWhileIdle=true
spring.datasource.admindb.timeBetweenEvictionRunsMillis=300000
spring.datasource.admindb.numTestsPerEvictionRun=50
spring.datasource.admindb.minEvictableIdleTimeMillis=3600000

三、数据源配置文件

一个数据源一个配置文件，这里列举出一个完整的配置例子，不同的数据源只需要更改bean名称以及路径即可。

import com.github.pagehelper.PageHelper;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;
import java.util.Properties;

@Configuration
@MapperScan(basePackages = UserDatasource.PACKAGE, sqlSessionTemplateRef  = "userdb")
public class UserDatasource {

    // 精确到 mapper 目录，以便跟其他数据源隔离
    static final String PACKAGE = "com.boot.framework.mapper.userdb";
    static final String MAPPER_LOCATION = "classpath:mapping/userdb/*.xml";

    @Bean(name = "userdbDatasource")
    @ConfigurationProperties(prefix = "spring.datasource.userdb")
    @Primary  //标记为主数据源，当数据源不确定时会默认选择主数据源，必须并只能在一个文件中使用该注解
    public DataSource textDatasource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "userSqlSessionFactory")
    @Primary
    public SqlSessionFactory textSessionFactory(@Qualifier("userdbDatasource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources(UserDatasource.MAPPER_LOCATION));

        //分页拦截器-start 添加分页插件，若无该需求可不配置
        Interceptor[] plugins = new Interceptor[]{pageHelper()};
        bean.setPlugins(plugins);
        // 分页拦截器-end
        return bean.getObject();
    }

	//事务管理
    @Bean(name = "userTransactionManager")
    public DataSourceTransactionManager userTransactionManager(@Qualifier("userdbDatasource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "userdb")
    @Primary
    public SqlSessionTemplate textSessionTemplat(@Qualifier("userSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

	//分页插件配置
    public PageHelper pageHelper() {
        PageHelper pageHelper = new PageHelper();
        Properties p = new Properties();
        p.setProperty("offsetAsPageNum", "true");
        p.setProperty("rowBoundsWithCount", "true");
        p.setProperty("reasonable", "true");
        p.setProperty("returnPageInfo", "check");
        p.setProperty("params", "count=countSql");
        pageHelper.setProperties(p);
        return pageHelper;
    }

}

因为使用了分页插件，所以就简单的举例来说明一下如何使用吧

是的，只需要在调用mapper接口前使用

PageHelper.startPage(“第几页”,“一页多少条数据”);

这时分页插件会自动拦截到下一次执行的sql，并动态的加上limit关键字，如：

如此配置基本就完成了，接下来可以通过 mybatis逆向工程 将model、mapper、xml文件生成出来。

至于多数据源事务问题可查看Springboot通过AOP多数据源事务处理