springboot实现多数据源配置（Druid/Hikari）-Toy模板网

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使用springboot+mybatis-plus+（Druid/Hikari）实现多数据源配置

操作步骤：

引入相应的maven坐标
编写mybatis配置，集成mybatis或mybatis-plus（如果已集成可跳过）
编写数据源配置类
编写注解，并通过aop进行增强（编写数据源切换代码）
类或方法中使用注解，对数据源进行切换

第一步：引入需要相应maven坐标

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

        <!-- aop注解实现aspectjweaver依赖 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.6</version>
        </dependency>
        <!-- mysql-plus 依赖 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.0</version>
        </dependency>
        <!-- Mysql驱动包 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--阿里数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.14</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

第二步：编写mybatis-plus配置集成

server:
  port: 8000

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    master:
      url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&allowMultiQueries=true
      username: root
      password: 123456
    slaver:
      # 从数据源开关/默认关闭
      enabled: false
      url: jdbc:mysql://localhost:3306/slave?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&allowMultiQueries=true
      username: root
      password: 123456
    druid:
      # 初始连接数
      initial-size: 5
      # 最小连接池数量
      min-idle: 10
      # 最大连接池数量
      max-active: 20
      # 获取连接等待超时时间
      max-wait: 60000
mybatis-plus:
  mapper-locations: classpath*:mapper/*Mapper.xml

logging:
  level:
    com.example.demo: debug

以下是集成mp相关的代码，不需要可直接跳过！！！(以user表为例)

userMapper

package com.example.demo.datesource.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.datesource.domain.User;

import java.util.List;

public interface UserService extends IService<User> {

    List<User> getUserList();
    List<User> getUserListByXml();

    List<User> testSlave();
}

userMapper.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="com.example.demo.datesource.mapper.UserMapper">


    <select id="getUserListByXml" resultType="com.example.demo.datesource.domain.User">
        select * from user
    </select>
</mapper>

userService

package com.example.demo.datesource.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.example.demo.datesource.domain.User;

import java.util.List;

public interface UserService extends IService<User> {

    List<User> getUserList();
    List<User> getUserListByXml();

    List<User> testSlave();
}

userServiceImpl

package com.example.demo.datesource.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.demo.datesource.annotation.UseDataSource;
import com.example.demo.datesource.domain.User;
import com.example.demo.datesource.enums.DataSourceType;
import com.example.demo.datesource.mapper.UserMapper;
import com.example.demo.datesource.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> getUserList() {
        return list();
    }

    @Override
    public List<User> getUserListByXml(){
        return userMapper.getUserListByXml();
    }

    @Override
    public List<User> testSlave() {
        return list();
    }
}

User

package com.example.demo.datesource.domain;

import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;

@Data
@TableName("user")
public class User {

    @TableId
    private Long id;

    private String name;

    private String sex;

    private int age;
}

mybatis-plus 集成完毕！

第三步：编写数据源的配置类（例：Druid、Hikari）

一、@ConfigurationProperties要和配置文件中的配置对应上

（1）Druid：

package com.example.demo.datesource.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.alibaba.druid.spring.boot.autoconfigure.properties.DruidStatProperties;
import com.example.demo.datesource.config.properties.DruidPropertiesConfig;
import com.example.demo.datesource.datasource.DynamicDataSource;
import com.example.demo.datesource.enums.DataSourceType;
import com.example.demo.datesource.utils.SpringUtils;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
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 javax.sql.DataSource;
import javax.swing.*;
import java.util.HashMap;
import java.util.Map;

@Configuration
public class DruidConfig {

    @Bean
    @ConfigurationProperties("spring.datasource.master")
    public DataSource masterDataSource(DruidPropertiesConfig propertiesConfig){
        DruidDataSource dataSource = DruidDataSourceBuilder.create().build();
        return propertiesConfig.setDataSourceProperties(dataSource);
    }

    @Bean
    @ConfigurationProperties("spring.datasource.slaver")
    @ConditionalOnProperty(prefix = "spring.datasource.slaver", name = "enabled", havingValue = "true")
    public DataSource slaverDataSource(DruidPropertiesConfig propertiesConfig){
        DruidDataSource dataSource = DruidDataSourceBuilder.create().build();
        return propertiesConfig.setDataSourceProperties(dataSource);
    }

    @Bean
    @Primary
    public DynamicDataSource dataSource(DataSource masterDataSource){
        Map<Object,Object> targetDataSource = new HashMap<>();
        targetDataSource.put(DataSourceType.MASTER.name(),masterDataSource);
        setDataSource(targetDataSource,DataSourceType.SLAVE.name(),"slaverDataSource");
        return new DynamicDataSource(masterDataSource,targetDataSource);
    }

    public void setDataSource(Map<Object,Object> targetDataSource,String sourceName,String beanName){
        try {
            DataSource dataSource = SpringUtils.getBean(beanName);
            targetDataSource.put(sourceName,dataSource);
        }catch (Exception e){

        }
    }

}

增加DruidPropertiesConfig类，用于给数据源配置上配置文件对应的属性

package com.example.demo.datesource.config.properties;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;

@Configuration
public class DruidPropertiesConfig {

    @Value("${spring.datasource.druid.initial-size}")
    private int initialSize;

    @Value("${spring.datasource.druid.min-idle}")
    private int minIdle;

    @Value("${spring.datasource.druid.max-active}")
    private int maxActive;

    @Value("${spring.datasource.druid.max-wait}")
    private int maxWait;

    public DruidDataSource setDataSourceProperties(DruidDataSource dataSource){
        dataSource.setInitialSize(this.initialSize);
        dataSource.setMinIdle(this.minIdle);
        dataSource.setMaxActive(this.maxActive);
        dataSource.setMaxWait(this.maxWait);
        return dataSource;
    }

}

（2）Hikari：配置上基本和druid相同，只需把配置类改为如下且配置文件的“url”改为“jdbc-url”即可

springboot多数据源druid,Java,spring boot,mybatis,java

二、增加SpringUtils类，用于读取spring中的bean

package com.example.demo.datesource.utils;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.stereotype.Component;

@Component
public class SpringUtils implements BeanFactoryPostProcessor {

    private static ConfigurableListableBeanFactory beanFactory;

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
        SpringUtils.beanFactory = configurableListableBeanFactory;
    }


    public static <T> T getBean(String name){
        return (T) beanFactory.getBean(name);
    }


}

三、添加DynamicDataSource类

（1）此类是用来配置动态数据源的关键。该类继承spring的抽象类AbstractRoutingDataSource，通过这个类可以实现动态数据源切换。其中维护着默认数据源（defaultTargetDataSource）和数据源列表（targetDataSources），通过afterPropertiesSet()方法对数据源列表进行解析以及设置数据源。
程序每次对数据库发起连接时，都会访问到AbstractRoutingDataSource的getConnection()方法，此方法会调用determineCurrentLookupKey的相应实现，此处实现为获取线程变量。

package com.example.demo.datesource.datasource;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

import javax.sql.DataSource;
import java.util.Map;

public class DynamicDataSource extends AbstractRoutingDataSource {

    public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources)
    {
        super.setDefaultTargetDataSource(defaultTargetDataSource);
        super.setTargetDataSources(targetDataSources);
        super.afterPropertiesSet();
    }

    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceContextHolder.getDataSourceType();
    }
}

（2）添加DynamicDataSourceContextHolder类，此类用于切换数据源，根据ThreadLocal做多线程数据隔离，每一次切换都能保证不影响其他线程的正常运行

package com.example.demo.datesource.datasource;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DynamicDataSourceContextHolder {

    public static final Logger log = LoggerFactory.getLogger(DynamicDataSourceContextHolder.class);

    private static final ThreadLocal<String> CONTEXT_HOLDER =  new ThreadLocal<>();

    /**
     * 设置数据源的变量
     */
    public static void setDataSourceType(String dsType){
        log.info("切换到{}数据源",dsType);
        CONTEXT_HOLDER.set(dsType);
    }


    /**
     * 获得数据源的变量
     */
    public static String getDataSourceType()
    {
        return CONTEXT_HOLDER.get();
    }

    /**
     * 清空数据源变量,此方法可调动gc对线程进行清除
     */
    public static void clearDataSourceType()
    {
        CONTEXT_HOLDER.remove();
    }

}

AbstractRoutingDataSource切换线程变量来切换数据源源码。
此处就是获取之前在DynamicDataSourceContextHolder中set到线程中的数据源名，通过数据源名获取维护的数据源列表中对应的数据源
springboot多数据源druid,Java,spring boot,mybatis,java

第四步：使用

大致思路：定义一个切换数据源注解，通过注解aop的形式对数据源进行切换，在类或方法中使用注解，设置对应的数据源名称以此来达到数据源切换

一、定义一个切换数据源注解

package com.example.demo.datesource.annotation;

import com.example.demo.datesource.enums.DataSourceType;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface UseDataSource {

    public DataSourceType dataSource() default DataSourceType.MASTER;

}

二、编写aop代码

@within：此注解可以作用于类中的所有方法，如果@UseDataSource放到类上，此类下的所有的方法都会被当做切点拦截
@Order(1)：提升组件注册到spring中的优先级
point.proceed()：原来执行的程序，也就是原请求，想要做环绕增强就再这周围写就可以了

package com.example.demo.datesource.aspectj;

import com.example.demo.datesource.annotation.UseDataSource;
import com.example.demo.datesource.datasource.DynamicDataSourceContextHolder;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import javax.sql.DataSource;
import java.util.Objects;

@Aspect
@Order(1)
@Component
public class DataSourceAspect {

    @Pointcut("@annotation(com.example.demo.datesource.annotation.UseDataSource) || @within(com.example.demo.datesource.annotation.UseDataSource)")
    public void pointCut(){}

    @Around("pointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable{
        UseDataSource useDataSource = getDataSource(point);
        if(Objects.nonNull(useDataSource)){
            DynamicDataSourceContextHolder.setDataSourceType(useDataSource.dataSource().name());
        }
        try {
            return point.proceed();
        }finally {
            //清空threadlocalMap的entry。避免内存泄漏
            DynamicDataSourceContextHolder.clearDataSourceType();
        }

    }

    public UseDataSource getDataSource(ProceedingJoinPoint point){
        MethodSignature signature = (MethodSignature) point.getSignature();
        UseDataSource annotation = AnnotationUtils.findAnnotation(signature.getMethod(), UseDataSource.class);
        if(Objects.nonNull(annotation)){
            return annotation;
        }
        return AnnotationUtils.findAnnotation(signature.getDeclaringType(),UseDataSource.class);
    }

}

三、编写注解到类或方法上

springboot多数据源druid,Java,spring boot,mybatis,java

运行结果：
springboot多数据源druid,Java,spring boot,mybatis,java

至此，数据源切换成功！！！

另外，如果需要增加新的数据源需要的操作：
1、启动配置文件中增加新的数据源参数
2、数据源配置类中，新增配置源bean，并且把数据源set到targetDataSource中
3、DataSourceType枚举类中，添加新数据源的枚举
如图所示：
springboot多数据源druid,Java,spring boot,mybatis,java