Spring Boot + MyBatis + Pagehelper 配置多数据源

前言：

本文为springboot结合mybatis配置多数据源，在项目当中很多情况是使用主从数据源来读写分离，还有就是操作多库，本文介绍如何一个项目同时使用2个数据源。

也希望大家带着思考去学习！博主是最近才学的配置写成博文分享心得和技巧，文中有不足的欢迎留言指正，谢谢！

思考：

　　1、如果从传统的单数据源转换为多数据源，以前使用boot只用导包写配置文件boot会帮我们自动配置，如果不用自动配置我们改怎么配呢？

　　2、怎么结合mybatis分页插件一起使用呢？

　　.................

　　

项目目录结构

对主从数据库分区，不同的数据源在不同的文件下易区分

创建2个数据库　　

DROP TABLE IF EXISTS `users`;
CREATE TABLE `users` (
  `id` bigint() NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `userName` varchar() DEFAULT NULL COMMENT '用户名',
  `passWord` varchar() DEFAULT NULL COMMENT '密码',
  `user_sex` varchar() DEFAULT NULL,
  `nick_name` varchar() DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT= DEFAULT CHARSET=utf8;

INSERT INTO `users` VALUES ('28', 'asd', 'asda', '1', 'asd');

　　使用一个表结构创建2个数据源  test1、test2

　　　

重要部分pom

<!-- mysql包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- 用于springboot热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- 阿里alibaba数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.6</version>
        </dependency>
        <!-- 添加JDBC依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>

pom.xml 文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>top.cmnbgy</groupId>
    <artifactId>spring-boot-ibatis-mulidatasource</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-ibatis-mulidatasource</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.17.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>
        <!-- mysql包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- 用于springboot热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- 阿里alibaba数据源 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.6</version>
        </dependency>
        <!-- 添加JDBC依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

创建application.yml 文件

# 指定项目端口
server:
  port: 

spring:
  datasource:
　　#主数据源
    master:
      driverClassName : com.mysql.jdbc.Driver
      url : jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8
      username : root
      password : 1234
　
　　#从数据源
    slave:
      driverClassName: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/test2?useUnicode=true&characterEncoding=utf-8
      username: root
      password:
#配置分页插件
pagehelper:
  helperDialect: mysql # 设置数据库类型
  reasonable: true #开启合理化：页码<= 查询第一页，页码>=总页数查询最后一页
  supportMethodsArguments: true #支持通过 Mapper 接口参数来传递分页参数
  params: count=countSql   # 参数  成员变量 = ${ xx}

　使用spring boot官方推荐的yml文件配置，结构更清晰！

创建主数据源配置类   MasterDataSource

　　

package top.cmnbgy.springbootibatismulidatasource.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
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.beans.factory.annotation.Value;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;
import java.io.IOException;

/**
 * 主数据源配置
 * @ClassName MasterDataSource
 * @Cescription TODO
 * @Author .朱孝辉
 * @Blog http://www.cmnbgy.top
 * @Datae 2018/11/14 0014 13:45
 **/
@Configuration
// basePackages ：设置为你的 mapper（主数据源）接口路径
@MapperScan(basePackages = "top.cmnbgy.springbootibatismulidatasource.mapper.master", sqlSessionTemplateRef  = "master-SqlSessionTemplate")
// ConfigurationProperties：读取application文件
@ConfigurationProperties(prefix = "spring.datasource.master")
public class MasterDataSource {

    private String url;
      private String username;
    private String password;
    private String driverClassName;

    /* ....... 忽略其他配置参数*/
    public String getDriverClassName() {
        return driverClassName;
    }

    public void setDriverClassName(String driverClassName) {
        this.driverClassName = driverClassName;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    /**
     * 创建主数据源
     * @return
     */
    @Bean(name = "master-DataSource")
    @Primary
   // @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource testDataSource() {
        /**
         *  @Bean：创建bean组件，可设置bean的name，如果不写name默认为方法名
         *  @Primary：设置为优先注入，如果Bean类型有多个，设置@Primary后会将该Bean优先注入，否则会报错
         *  @ConfigurationProperties：读取application.properties 属性封装成实体类
         *
         *  DataSourceBuilder.create().build() ：SpringBoot为我们提供了简便的创建数据源方式
         */
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        dataSource.setDriverClassName(driverClassName);
        return dataSource;
    }

    /**
     *      创建SqlSession工厂
     */
    @Primary
    @Bean(name = "master-SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("master-DataSource") DataSource dataSource) throws Exception {
        /**
         * @Qualifier：正常情况下，注入bean时，如果存在多个资源，就会出错，可以用@Qualifier指定名字
         */
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/master/*/*.xml"));
        return bean.getObject();
    }

    /**
     *  事务管理
     */
    @Primary
    @Bean(name="master-TransactionManager")
    public DataSourceTransactionManager masterTransactionManager(@Qualifier("master-DataSource") DataSource dataSource){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager(dataSource);
        return dataSourceTransactionManager;
    }

    /**
     *  配置sqlsession模板
     */
    @Primary
    @Bean("master-SqlSessionTemplate")
    public SqlSessionTemplate masterSQLSessionTemplate(@Qualifier("master-SqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

从数据源  SlaveDataSource

package top.cmnbgy.springbootibatismulidatasource.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
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.beans.factory.annotation.Value;
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 org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

/**
 * 从数据源配置
 * @ClassName SlaveDataSource
 * @Cescription TODO
 * @Author .朱孝辉
 * @Blog http://www.cmnbgy.top
 * @Datae 2018/11/14 0014 13:46
 **/

@Configuration
@MapperScan(basePackages = "top.cmnbgy.springbootibatismulidatasource.mapper.slave", sqlSessionTemplateRef  = "slave-SqlSessionTemplate")
@ConfigurationProperties(prefix = "spring.datasource.slave")
public class SlaveDataSource {

    private String url;
    private String username;
    private String password;
    private String driverClassName;

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getDriverClassName() {
        return driverClassName;
    }

    public void setDriverClassName(String driverClassName) {
        this.driverClassName = driverClassName;
    }

    /**
     * 创建主数据源
     * @return
     */
    @Bean(name = "slave-DataSource")
    // @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource testDataSource() {
        /**
         *  @Bean：创建bean组件，可设置bean的name，如果不写name默认为方法名
         *  @Primary：设置为优先注入，如果Bean类型有多个，设置@Primary后会将该Bean优先注入，否则会报错
         *  @ConfigurationProperties：读取application.properties 属性封装成实体类
         *
         *  DataSourceBuilder.create().build() ：SpringBoot为我们提供了简便的创建数据源方式
         */
        System.out.println("================================"+url);
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(url);
        dataSource.setUsername(username);// 用户名
        dataSource.setPassword(password);// 密码
        dataSource.setDriverClassName(driverClassName);
        return dataSource;
    }

    /**
     *      创建SqlSession工厂
     */
    @Bean(name = "slave-SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("slave-DataSource") DataSource dataSource) throws Exception {
        /**
         * @Qualifier：
         */
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/slave/*/*.xml"));
        return bean.getObject();
    }

    /**
     *  事务管理
     */
    @Bean(name="slave-TransactionManager")
    public DataSourceTransactionManager masterTransactionManager(@Qualifier("slave-DataSource") DataSource dataSource){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager(dataSource);
        return dataSourceTransactionManager;
    }

    /**
     *  配置sqlsession模板
     */
    @Bean("slave-SqlSessionTemplate")
    public SqlSessionTemplate masterSQLSessionTemplate(@Qualifier("slave-SqlSessionFactory") SqlSessionFactory sqlSessionFactory){
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

• @Configuration ：用于定义配置类，告诉springboot这是配置类。

• @ConfigurationProperties：读取application配置文件

• @Bean：创建bean组件，可设置bean的name，如果不写name默认为方法名

• @Primary：设置为优先注入，如果Bean类型有多个，设置@Primary后会将该Bean优先注入，否则会报错

• @ConfigurationProperties：读取application.properties 属性封装成实体类

• @Qualifier：正常情况下，注入bean时，如果存在多个资源，就会出错，可以用@Qualifier指定名字

• @MapperScan：ibatis提供的注解，注解包路径 package org.mybatis.spring.annotation;

• basePackages：要扫描mapper类包的路径

• sqlSessionTemplateRef：sqlSessionTemplateRef Bean的名称

　　注意：关于bean的命名　masterDataSource  以前我是这样命名的，最后一直报错，排查后发现spring容器中也有一个 名称为masterDataSource的bean，所以起冲突了。

　　

创建mapper接口和xml

创建文件夹 top.cmnbgy.springbootibatismulidatasource.mapper.master 

用于放  主数据源 mapper接口类  UsersMapper.java

package top.cmnbgy.springbootibatismulidatasource.mapper.master;

import java.util.List;

/**
 * @ClassName UsersMapper
 * @Cescription TODO
 * @Author .朱孝辉
 * @Blog http://www.cmnbgy.top
 * @Datae 2018/11/15 0015 9:57
 **/
public interface UsersMapper {
    List selectAll();
}

创建文件夹 top.cmnbgy.springbootibatismulidatasource.mapper.slave

再创建一个从数据源 mapper接口  Users1Mapper.java

package top.cmnbgy.springbootibatismulidatasource.mapper.slave;

import java.util.List;

/**
 * @ClassName UsersMapper
 * @Cescription TODO
 * @Author .朱孝辉
 * @Blog http://www.cmnbgy.top
 * @Datae 2018/11/15 0015 9:57
 **/
public interface Users1Mapper {
    List selectAll();
}

　　

　创建mapperXMl

创建 master 文件夹下面 的 UsersMapper.xml  文件

为了省步骤，我直接用HashMap 做载体，就不用写实体类了

<?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="top.cmnbgy.springbootibatismulidatasource.mapper.master.UsersMapper" >
    <select id="selectAll" resultType="map">
        select * from users
    </select>
</mapper>

创建 slave文件夹下面 的 UsersMapper.xml  文件

<?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="top.cmnbgy.springbootibatismulidatasource.mapper.slave.Users1Mapper" >
    <select id="selectAll" resultType="map">
        select * from users
    </select>
</mapper>

resultType="map"  映射返回类型可以使用别名

我在贴一份别名的表，这些都是mybatis 自带的 别名配置，你也可以自定义别名

https://blog.csdn.net/qq_28885149/article/details/51694733

【ღ( ´･ᴗ･` )比心】

别名	映射的类型
_byte	byte
_long	long
_short	short
_int	int
_integer	int
_double	double
_float	float
_boolean	boolean
string	String
byte	Byte
long	Long
short	Short
int	Integer
integer	Integer
double	Double
float	Float
boolean	Boolean
date	Date
decimal	BigDecimal
bigdecimal	BigDecimal
object	Object
map	Map
hashmap	HashMap
list	List
arraylist	ArrayList
collection	Collection
iterator	Iterator

　　

★华丽分割线 ★   注意点

---

注意：

　　检查下 数据源配置文件（Master | SlaveDataSource）的

看看有没有对应上，Master  和 Slave 别混淆，如果报 哪个XML的某个 sql 没匹配上，请仔细检查一下以上的路径是否正确！

★华丽分割线 ★   最后的测试环节

---

package top.cmnbgy.springbootibatismulidatasource;

import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import org.apache.ibatis.annotations.Select;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import top.cmnbgy.springbootibatismulidatasource.mapper.master.UsersMapper;
import top.cmnbgy.springbootibatismulidatasource.mapper.slave.Users1Mapper;

import javax.annotation.Resource;
import javax.sql.DataSource;
import java.awt.image.Kernel;
import java.sql.SQLException;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootIbatisMulidatasourceApplicationTests {

    @Resource(name = "master-DataSource")
    DataSource masterDataSource;

    @Resource(name = "slave-DataSource")
    DataSource slaveDataSource;

    /**
     * 主数据源
     */
    @Autowired
    UsersMapper usersMapper;

    /**
     * 从数据源
     */
    @Autowired
    Users1Mapper users1Mapper;

    @Test
    public void contextLoads() throws SQLException {
        System.out.println("==========================================================");
        System.out.println("主数据源："+masterDataSource);
        System.out.println("从数据源："+slaveDataSource);
        // 开启分页
        System.out.println("主数据源：");
        Page page = PageHelper.startPage(1,10);
        System.out.println(usersMapper.selectAll());
        usersMapper.selectAll().forEach(item->System.out.println(item));
        System.out.println("总页数："+page.getTotal());
        //-----------------------------------------------------------
        System.out.println("从数据源：");
        Page page1 = PageHelper.startPage(1,10);
        System.out.println(users1Mapper.selectAll().toString());
        System.out.println(page1.getTotal());
        System.out.println("总页数："+page1.getTotal());
        users1Mapper.selectAll().forEach(item->System.out.println(item));
        System.out.println("==========================================================");
    }

}

ok 测试！！！！！！！

PageHelper文档：   https://pagehelper.github.io/

　  某个大神的SpringBoot 技术博客 ：http://tengj.top/2017/02/26/springboot1/

　

★华丽分割线 ★   结尾

---

    教程结束！

　喜欢该博文的同学和点赞关注ღ( ´･ᴗ･` )比心

　文中如有不足，欢迎指正和讨论！❤

　作者QQ：1983127490 

　代码以上传码云

　码云：https://gitee.com/gezi441/spring-boot-ibatis-mulidatasource