Spring Boot + MyBatis + Pagehelper 配置多数据源

Posted 2021-01-20 知秋

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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(20) NOT NULL AUTO_INCREMENT COMMENT \'主键id\',
  `userName` varchar(32) DEFAULT NULL COMMENT \'用户名\',
  `passWord` varchar(32) DEFAULT NULL COMMENT \'密码\',
  `user_sex` varchar(32) DEFAULT NULL,
  `nick_name` varchar(32) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=35 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: 8080

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: 1234
#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<=0 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】

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