一、前言

本教程主要内容

  • 使用Spring Boot+MyBatis访问多个数据源

本教程开发环境

1、操作系统： Windows 10 X64
2、Java SDK： jdk-8u141
3、Maven：3.5
4、IDE：IntelliJ IDEA 2017
5、Spring Boot：1.5.6

本项目构建基于：https://ken.io/note/springboot-course-basic-curd-xml

二、多数据源配置

1、创建数据库&表

  • 创建数据库test 
CREATE DATABASE test;
  • 创建表：note
DROP TABLE IF EXISTS `note`;
CREATE TABLE `note` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(255) DEFAULT NULL,
  `body` longtext,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

2、修改配置文件增加数据源

修改数据库连接配置(application.yml)，将之前的spring.datasource更换为自定义的courseDataSource、testDataSource

#数据库连接配置
courseDataSource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/course?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
    username: root
    password: root

testDataSource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
    username: root
    password: root

3、调整数据源对应实体

1、在io.ken.springboot.course.model下新建两个package：course、test
2、将User.java移动到io.ken.springboot.course.model.course
3、在io.ken.springboot.course.model.test下新建Note.java 

package io.ken.springboot.course.model.test;

public class Note {

    private int id;

    private String title;

    private String body;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }
}

4、配置数据源对应Configuration

1、在io.ken.springboot.course.dao下新建两个package：course、test
2、将UserMapper.java移动到io.ken.springboot.course.dao.course并去掉@Mapper注解
3、在io.ken.springboot.course.dao.test下新建NoteMapper.java 

package io.ken.springboot.course.dao.test;

import io.ken.springboot.course.model.test.Note;

import java.util.List;

public interface NoteMapper {

    List<Note> queryAll();
}

5、调整MyBatis Mappere配置

1、在/resources/conf/mybatis/mapper下新建两个文件夹：course、test
2、将UserMapper.xml移动到/resources/conf/mybatis/mapper/course
3、在/resources/conf/mybatis/mapper/test下新建NoteMapper.xml 

<?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="io.ken.springboot.course.dao.test.NoteMapper">

    <select id="queryAll" resultType="io.ken.springboot.course.model.test.Note">
        SELECT * FROM note
    </select>

</mapper>

6、配置数据源对应Configuration

1、在io.ken.springboot.course下新建package：config
2、在io.ken.springboot.course.config下创建CourseDbConfig.java 

package io.ken.springboot.course.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
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 javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "io.ken.springboot.course.dao.course", sqlSessionFactoryRef = "courseSqlSessionFactory")
public class CourseDbConfig {

    @Bean(name = "courseDataSource")
    @ConfigurationProperties(prefix = "courseDataSource")
    @Primary
    public DataSource courseDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "courseSqlSessionFactory")
    @Primary
    public SqlSessionFactory courseSqlSessionFactory(@Qualifier("courseDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:conf/mybatis/mapper/course/*.xml"));
        return bean.getObject();
    }

}

3、在io.ken.springboot.course.config下创建TestDbConfig.java

package io.ken.springboot.course.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "io.ken.springboot.course.dao.test", sqlSessionFactoryRef = "testSqlSessionFactory")
public class TestDbConfig {

    @Bean(name = "testDataSource")
    @ConfigurationProperties(prefix = "testDataSource")
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

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

}

7、创建NoteController并提供API

package io.ken.springboot.course.controller;

import io.ken.springboot.course.dao.test.NoteMapper;
import io.ken.springboot.course.model.test.Note;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

@Controller
@RequestMapping("/note")
public class NoteController {

    @Autowired
    NoteMapper noteMapper;

    @RequestMapping("/queryall")
    @ResponseBody
    List<Note> queryAll() {
        return noteMapper.queryAll();
    }
}

8、API测试

API 示例
添加用户 /user/add?name=tom&age=1&hobby=football
更新用户 /user/updatebyid?name=ken&age=18&hobby=coding&id=1
查询指定用户 /user/querybyid?id=1
查询所有用户 /user/queryall
删除指定用户 /user/delbyid?id=2
查询所有日志 /note/queryall

三、备注

  • 本文代码示例

https://github.com/ken-io/springboot-course/tree/master/chapter-02-04