springboot-用dynamic-datasource-spring-boot-starter配置druid多数据源

前言：

dynamic-datasource插件是一款动态数据源的轻量级实现,封装成Spring Starter方式引入,
支持Mybatis、MybatisPlus读写分离,支持通过注解动态切换切换数据源。

1：项目结构

1：项目背景

在项目中访问两个数据库，分别打印出来两个数据库的数据信息

2：项目结构

3：项目地址

https://gitee.com/cangyu1024/spring-druid.git

2：导包

 <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
<!--            <exclusions>-->
<!--                <exclusion>-->
<!--                    <groupId>org.springframework.boot</groupId>-->
<!--                    <artifactId>spring-boot-starter-logging</artifactId>-->
<!--                </exclusion>-->
<!--            </exclusions>-->
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>2.1.3</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <!--这就是苞米豆的dynamic的多数据源配置-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.23</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>


    </dependencies>

主要的包是：苞米豆的dynamic的多数据源配置包

 <!--这就是苞米豆的dynamic的多数据源配置-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>

3:配置

1:pom.xml配置

spring:
  application:
    name: spring-druid
  #开始配置数据源
  datasource:
    dynamic:
      #指定一个主数据源,primary表示是主数据源也可以认为是默认数据源，如果不加注解DS(“数据源名字”)则会去主数据源中查询
      primary: db1
      datasource:
        #第一个数据源配置
        db1:
          driver-class-name: com.mysql.jdbc.Driver
          url: jdbc:mysql://localhost:3306/db1?characterEncoding=utf8&useSSL=false&autoReconnect=true&serverTimezone=UTC
          username: root
          password: 6DEPiNLAN3mfjBEX
          type: com.alibaba.druid.pool.DruidDataSource
          druid:
            initial-size: 5 #连接池初始化大小
            min-idle: 10 #最小空闲连接数
            max-active: 20 #最大连接数
            filters: stat,log4j
        #第二个数据源配置
        db2:
          driver-class-name: com.mysql.jdbc.Driver
          url: jdbc:mysql://localhost:3306/db2?characterEncoding=utf8&useSSL=false&autoReconnect=true&serverTimezone=UTC
          username: root
          password: 6DEPiNLAN3mfjBEX
          type: com.alibaba.druid.pool.DruidDataSource
          druid:
            initial-size: 5 #连接池初始化大小
            min-idle: 10 #最小空闲连接数
            max-active: 20 #最大连接数
            filters: stat,log4j
    druid:
      web-stat-filter:
        exclusions: "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*" #不统计这些请求数据
      #开启druid的监控面板
      stat-view-servlet:
        enabled: true #为true就是开启
        login-username: root
        login-password: root
        # IP白名单 (没有配置或者为空，则允许所有访问)
        #allow: 127.0.0.1,192.168.163.1
        # IP黑名单 (存在共同时，deny优先于allow)
        #deny: 192.168.10.1
#mybatis
mybatis:
  #扫描Mapper接口对应的XML文件
  mapper-locations:
    - classpath*:mapper/*.xml
  #使用mybatis.type-aliases-package来指定POJO扫描包来让mybatis自动扫描到自定义的POJO。
  type-aliases-package: com.wkl.springdruid.dto
  #如果查询语句中某些字段值是null的，则这个字段就无法返回。对于后台数据处理来说，这是一个致命的问题，于是通过修改Mybatis的配置来解决这个问题。返回一个null的值
  configuration:
    call-setters-on-nulls: true


server:
  port: 8080

2：引入log4j.xml日志配置,要不然会报错

网上随便找的就行

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="OFF">
    <appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <!--只接受程序中DEBUG级别的日志进行处理-->
            <ThresholdFilter level="DEBUG" onMatch="ACCEPT" onMismatch="DENY"/>
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n"/>
        </Console>
        <!--处理INFO级别的日志，并把该日志放到logs/info.log文件中-->
        <RollingFile name="RollingFileInfo" fileName="./logs/info.log"
                     filePattern="logs/$${date:yyyy-MM}/info-%d{yyyy-MM-dd}-%i.log.gz">
            <Filters>
                <ThresholdFilter level="INFO"/>
                <ThresholdFilter level="WARN" onMatch="DENY" onMismatch="NEUTRAL"/>
            </Filters>
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="500 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>
        <!--处理WARN级别的日志，并把该日志放到logs/warn.log文件中-->
        <RollingFile name="RollingFileWarn" fileName="./logs/warn.log"
                     filePattern="logs/$${date:yyyy-MM}/warn-%d{yyyy-MM-dd}-%i.log.gz">
            <Filters>
                <ThresholdFilter level="WARN"/>
                <ThresholdFilter level="ERROR" onMatch="DENY" onMismatch="NEUTRAL"/>
            </Filters>
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="500 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>
        <!--处理error级别的日志，并把该日志放到logs/error.log文件中-->
        <RollingFile name="RollingFileError" fileName="./logs/error.log"
                     filePattern="logs/$${date:yyyy-MM}/error-%d{yyyy-MM-dd}-%i.log.gz">
            <ThresholdFilter level="ERROR"/>
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="500 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>
        <!--druid的日志记录追加器-->
        <RollingFile name="druidSqlRollingFile" fileName="./logs/druid-sql.log"
                     filePattern="logs/$${date:yyyy-MM}/api-%d{yyyy-MM-dd}-%i.log.gz">
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%file:%line] %-5level %logger{35} - %msg %n"/>
            <Policies>
                <SizeBasedTriggeringPolicy size="500 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>
    </appenders>
    <loggers>
        <AsyncRoot level="info">
            <appender-ref ref="Console"/>
            <appender-ref ref="RollingFileInfo"/>
            <appender-ref ref="RollingFileWarn"/>
            <appender-ref ref="RollingFileError"/>
        </AsyncRoot>
        <!--记录druid-sql的记录-->
        <AsyncLogger name="druid.sql.Statement" level="debug" additivity="false">
            <appender-ref ref="druidSqlRollingFile"/>
        </AsyncLogger>
    </loggers>
</configuration>

4：编码

1：分别在两个库随便建个表

2：创建实体类

package com.wkl.springdruid.dto;

import lombok.Data;

/**
 * @author wangkanglu
 * @version 1.0
 * @description
 * @date 2022-10-14 16:11
 */
@Data
public class TestDto {
    
    
    Integer id;
    String name;
}

3：创建dao实现类-指定数据源

说明:用DS注解指明要使用的数据，
       dynamic-datasource官方建议把注解添加到service的方法上
       如果不写这个注解的话，那么就使用默认数据源

package com.wkl.springdruid.mapper;

import com.baomidou.dynamic.datasource.annotation.DS;
import com.wkl.springdruid.dto.TestDto;
import org.apache.ibatis.annotations.Select;

import java.util.List;

/**
 * @author wangkanglu
 * @version 1.0
 * @description
 * @date 2022-10-14 16:12
 */
public interface TestMapper {
    
    
    @Select("select * from test1")
    @DS("db1")
    List<TestDto> selectAll1();


    @Select("select * from test2")
    @DS("db2")
    List<TestDto> selectAll2();


    @DS("db1")
    List<TestDto> selectAll3();
}

4：mybatis配置相关设置

在application.yml中配置xml扫描的路径和对应的其他配置

在主程序中配置扫描Mapper接口类的位置。

5：mybatis的xml相关配置

<?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="com.wkl.springdruid.mapper.TestMapper">

<select id="selectAll3" resultType="com.wkl.springdruid.dto.TestDto">
    select * from test1
</select>

</mapper>

5：测试

1:测试代码

package com.wkl.springdruid;

import com.wkl.springdruid.dto.TestDto;
import com.wkl.springdruid.mapper.TestMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import javax.annotation.Resource;
import java.util.List;

@SpringBootTest
class SpringDruidApplicationTests {
    
    


    @Resource
    TestMapper testMapper;

    @Test
    void contextLoads() {
    
    
    }

    
    @Test
    public void test1(){
    
    
        List<TestDto> testDtos = testMapper.selectAll1();
        System.out.println(testDtos);
    }

    @Test
    public void test2(){
    
    
        List<TestDto> testDtos = testMapper.selectAll2();
        System.out.println(testDtos);
    }

    @Test
    public void test3(){
    
    
        List<TestDto> testDtos = testMapper.selectAll3();
        System.out.println(testDtos);
    }
}

2:测试结果