springboot之配置多个数据源

多数据源应用场景

使用mabatis框架+druid数据源
当业务量达到一定量的时候，DataBase需要合理配置数据库资源，即把高频访问的数据放在主库上，低频访问的数据放在从库上，从而达到服务器CPU的合理应用。


image.png

多数据源应用

准备两个数据库，taotao和pms

image.png

新建springboot工程

选择web与mybatis

pom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>com.enowsh</groupId>
    <artifactId>boot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>boot-mybatis</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.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-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>ch.qos.logback</groupId>
                    <artifactId>logback-classic</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.9</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.5</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>3.4.2</version>
        </dependency>
    </dependencies>

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


</project>

工程结构

image.png

application.properties配置文件

#多个数据源配置
#master数据源配置
master.datasource.url=jdbc:mysql://localhost:3306/pms?characterEncoding=utf-8
master.datasource.username=root
master.datasource.password=wyx2020
master.datasource.driverClassName=com.mysql.jdbc.Driver 

#cluster数据源配置
cluster.datasource.url=jdbc:mysql://localhost:3306/taotao?characterEncoding=utf-8
cluster.datasource.username=root
cluster.datasource.password=wyx2020
cluster.datasource.driverClassName=com.mysql.jdbc.Driver

主从数据源的配置-使用java代码

主数据源配置

package com.enowsh.boot_mybatis.config.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
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.beans.factory.annotation.Value;
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;
import java.io.IOException;

/**
 * @author:wong
 */
@Configuration
//扫描mapper接口包
@MapperScan(basePackages = "com.enowsh.boot_mybatis.mapper.master",sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterDataSourceConfig {

    @Value("${master.datasource.url}")
    private String masterDataSourceUrl;

    @Value("${master.datasource.username}")
    private String masterDatasourceUsername;

    @Value("${master.datasource.password}")
    private String masterDatasourcePassword;

    @Value("${master.datasource.driverClassName}")
    private String masterDatasourceDriverClassName;

    //定义dataSource的bean
    @Bean(name = "masterDataSource")
    @Primary //primary注解标志如果有多类同类bean候选，则优先考虑该bean，即主数据源
    public DataSource masterDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUsername(masterDatasourceUsername);
        dataSource.setPassword(masterDatasourcePassword);
        dataSource.setDriverClassName(masterDatasourceDriverClassName);
        dataSource.setUrl(masterDataSourceUrl);
        return dataSource;
    }

    //定义sqlSessionFactory的bean
    @Bean(name = "masterSqlSessionFactory")
    @Primary
    //使用@Qualifier注解同样是注入bean，但该注入方式是查找bean的name
    //@Autowired注入是根据bean的类型来查找bean注入
    public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        //扫描mapper.xml文件
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/master/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }
}
  • 其中类头上需要扫描mapper的接口包，将接口bean注入到容器
  • @Primary注解：如果有多个同类型的bean配置，则优先配置该bean，即主数据源的bean
  • @Qualifier("beanName")注解：与@Autowired不同的是，Qualifer是根据bean的name来查找bean，Autowired是根据类型查找，由于有多个数据源的bean，所以若使用Autowired则会查找到多个同类型的bean，不能识别，这时，需要使用Qualifer根据bean的名称注入
  • sqlSessionFactoryBean设置mapper的Location是指设置mapper.xml文件的location

从数据源参考主数据源

package com.enowsh.boot_mybatis.config.dataSource;

import com.alibaba.druid.pool.DruidDataSource;
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.beans.factory.annotation.Value;
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;
import java.io.IOException;

/**
 * @author:wong
 */
@Configuration
//扫描mapper接口包
@MapperScan(basePackages = "com.enowsh.boot_mybatis.mapper.cluster",sqlSessionFactoryRef = "clusterSqlSessionFactory")
public class ClusterDataSourceConfig {

    @Value("${cluster.datasource.url}")
    private String clusterDataSourceUrl;

    @Value("${cluster.datasource.username}")
    private String clusterDatasourceUsername;

    @Value("${cluster.datasource.password}")
    private String clusterDatasourcePassword;

    @Value("${cluster.datasource.driverClassName}")
    private String clusterDatasourceDriverClassName;

    //定义dataSource的bean
    @Bean(name = "clusterDataSource")
    public DataSource clusterDataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUsername(clusterDatasourceUsername);
        dataSource.setPassword(clusterDatasourcePassword);
        dataSource.setDriverClassName(clusterDatasourceDriverClassName);
        dataSource.setUrl(clusterDataSourceUrl);
        return dataSource;
    }

    //定义sqlSessionFactory的bean
    @Bean(name = "clusterSqlSessionFactory")
    //使用@Qualifier注解同样是注入bean，但该注入方式是查找bean的name
    //@Autowired注入是根据bean的类型来查找bean注入
    public SqlSessionFactory clusterSqlSessionFactory(@Qualifier("clusterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        //扫描mapper.xml文件
        sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/cluster/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }
}

编写service程序测试

package com.enowsh.boot_mybatis.service.impl;

import com.enowsh.boot_mybatis.mapper.cluster.TbUserMapper;
import com.enowsh.boot_mybatis.mapper.master.PmsUserMapper;
import com.enowsh.boot_mybatis.pojo.PmsResult;
import com.enowsh.boot_mybatis.pojo.PmsUser;
import com.enowsh.boot_mybatis.pojo.TbUser;
import com.enowsh.boot_mybatis.service.MutiDataSourceService;
import com.sun.org.apache.bcel.internal.generic.IF_ACMPEQ;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.ArrayList;
import java.util.List;

/**
 * @author:wong
 */
@Service
@Transactional
public class MutiDataSourceServiceImpl implements MutiDataSourceService {
    @Autowired
    private TbUserMapper tbUserMapper;

    @Autowired
    private PmsUserMapper pmsUserMapper;

    @Override
    public PmsResult findDifferentUser(long pmsId, long taotaoId) {
        PmsUser pmsUser = pmsUserMapper.selectByPrimaryKey(pmsId);
        TbUser tbUser = tbUserMapper.selectByPrimaryKey(taotaoId);
        if (pmsUser==null||tbUser==null)
            return PmsResult.build(400,"用户查询失败");
        List list=new ArrayList();
        list.add(pmsUser);
        list.add(tbUser);
        return PmsResult.ok(list);
    }
}

controller程序

package com.enowsh.boot_mybatis.controller;

import com.enowsh.boot_mybatis.pojo.PmsResult;
import com.enowsh.boot_mybatis.service.MutiDataSourceService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.annotation.security.PermitAll;

/**
 * @author:wong
 */
@Controller
public class MutiDataSourceController {
    @Autowired
    private MutiDataSourceService mutiDataSourceService;

    @RequestMapping("/muti/{taotaoId}/{pmsId}")
    @ResponseBody
    public PmsResult findUser(@PathVariable long taotaoId, @PathVariable long pmsId){
        PmsResult pmsResult = mutiDataSourceService.findDifferentUser(pmsId, taotaoId);
        return pmsResult;
    }
}

测试结果

image.png
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