# SpringBoot多数据源配置

**Repository Path**: radish2020/springboot-dynamic-datasource

## Basic Information

- **Project Name**: SpringBoot多数据源配置
- **Description**: 基于Springboot的三种多数据源配置方法
- **Primary Language**: Java
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 3
- **Forks**: 1
- **Created**: 2023-12-16
- **Last Updated**: 2024-03-01

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# 一、使用Spring提供的AbstractRoutingDataSource

主要代码：

application.yml

``` java
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    radish:
      url: jdbc:mysql://127.0.0.1:3306/radish?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF8&useSSL=false
      username: root
      password: 123456
      initial-size: 1
      min-idle: 1
      max-active: 20
      test-on-borrow: true
      driver-class-name: com.mysql.cj.jdbc.Driver
    radish1:
      url: jdbc:mysql://127.0.0.1:3306/radish2?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF8&useSSL=false
      username: root
      password: 123456
      initial-size: 1
      min-idle: 1
      max-active: 20
      test-on-borrow: true
      driver-class-name: com.mysql.cj.jdbc.Driver
```

DataSourceConfig.java

```java
package com.radish.config;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.radish.helper.DynamicDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
public class DataSourceConfig {
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.radish")
    public DataSource radish() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.radish1")
    public DataSource radish1() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    public DataSourceTransactionManager transactionManager1(DynamicDataSource radish){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
        dataSourceTransactionManager.setDataSource(radish);
        return dataSourceTransactionManager;
    }

    @Bean
    public DataSourceTransactionManager transactionManager2(DynamicDataSource radish){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
        dataSourceTransactionManager.setDataSource(radish);
        return dataSourceTransactionManager;
    }
}
```

DynamicDataSource.java

```java
package com.radish.helper;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.stereotype.Component;

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

@Component
@Primary
public class DynamicDataSource extends AbstractRoutingDataSource {
    // 当前使用的数据源标识
    public static ThreadLocal<String> name = new ThreadLocal<>();

    // 写
    @Autowired
    DataSource radish;

    // 读
    @Autowired
    DataSource radish1;

    @Override
    protected Object determineCurrentLookupKey() {
        return name.get();
    }

    @Override
    public void afterPropertiesSet() {
        // 为targetDataSources初始化所有数据源
        Map<Object, Object> targetDataSources=new HashMap<>();
        targetDataSources.put("W",radish);
        targetDataSources.put("R",radish1);

        super.setTargetDataSources(targetDataSources);
        // 为defaultTargetDataSource 设置默认的数据源
        super.setDefaultTargetDataSource(radish);
        super.afterPropertiesSet();
    }
}
```



# 二、使用MyBatis注册多个SqlSessionFactory

使用MyBatis多数据源，需要将MyBatis底层的DataSource、SqlSessionFactory、DataSourceTransactionManager这些核心对象一并进行手动注册。

核心代码：

读库注册

```java
@Configuration
// 继承mybatis:
// 1. 指定扫描的mapper接口包（主库）
// 2. 指定使用sqlSessionFactory是哪个（主库）
@MapperScan(basePackages = "com.radish.dao.r")
public class RMybatisConfig {

    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.radish")
    public DataSource radish() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @Primary
    public SqlSessionFactory rSqlSessionFactory() throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        // 指定主库
        sessionFactory.setDataSource(radish());
        // 指定主库对应的mapper.xml文件
        /*sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources("classpath:mapper/r/*.xml"));*/
        return sessionFactory.getObject();
    }

    @Bean
    public DataSourceTransactionManager rTransactionManager() {
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
        dataSourceTransactionManager.setDataSource(radish());
        return dataSourceTransactionManager;
    }

    @Bean
    public TransactionTemplate rTransactionTemplate(){
        return new TransactionTemplate(rTransactionManager());
    }
}
```

写库注册
```java
@Configuration
// 继承mybatis:
// 1. 指定扫描的mapper接口包（主库）
// 2. 指定使用sqlSessionFactory是哪个（主库）
@MapperScan(basePackages = "com.radish.dao.w",
        sqlSessionFactoryRef="wSqlSessionFactory")
public class WMyBatisConfig {
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.radish2")
    public DataSource radish2() {
        // 底层会自动拿到spring.datasource中的配置， 创建一个DruidDataSource
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @Primary
    public SqlSessionFactory wSqlSessionFactory()
            throws Exception {
        final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        // 指定主库
        sessionFactory.setDataSource(radish2());
        // 指定主库对应的mapper.xml文件
        /*sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources("classpath:mapper/order/*.xml"));*/
        return sessionFactory.getObject();
    }

    @Bean
    @Primary
    public DataSourceTransactionManager wTransactionManager(){
        DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
        dataSourceTransactionManager.setDataSource(radish2());
        return dataSourceTransactionManager;
    }


    @Bean
    public TransactionTemplate wTransactionTemplate(){
        return new TransactionTemplate(wTransactionManager());
    }
}
```



# 三、使用dynamic-datasource框架 

dynamic-datasource是MyBaits-plus作者设计的一个多数据源开源方案。使用这个框架需要引入对应的pom依赖 

```xml
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>3.5.0</version>
</dependency>
```

这样就可以在SpringBoot的配置文件中直接配置多个数据源

```yml
spring:
  datasource:
    dynamic:
      #设置默认的数据源或者数据源组,默认值即为master
      primary: master
      #严格匹配数据源,默认false. true未匹配到指定数据源时抛异常,false使用默认数据源
      strict: false
      datasource:
        master:
          url: jdbc:mysql://127.0.0.1:3306/datasource1?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF8&useSSL=false
          username: root
          password: 123456
          initial-size: 1
          min-idle: 1
          max-active: 20
          test-on-borrow: true
          driver-class-name: com.mysql.cj.jdbc.Driver
        slave_1:
          url: jdbc:mysql://127.0.0.1:3306/datasource2?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF8&useSSL=false
          username: root
          password: 123456
          initial-size: 1
          min-idle: 1
          max-active: 20
          test-on-borrow: true
          driver-class-name: com.mysql.cj.jdbc.Driver
```

这样就配置完成了master和slave_1两个数据库。
接下来在使用时，只要在对应的方法或者类上添加@DS注解即可。例如 

```java
@Service
public class TestServiceImpl implements ITestService {
    @Autowired
    private TestMapper testMapper;

    @Override
    @DS("slave") // 从库，如果按照下划线命名方式配置多个，可以指定前缀即可（组名）
    public List<PersonInfo> list() {
        return testMapper.list();
    }

    @Override
    @DS("#session.userID")
    @DSTransactional
    public void save(PersonInfo personInfo) {
        testMapper.save(personInfo);
    }
}
```