springboot,mysql多数据源-mybaits

为啥要多数据源，因为我现在有个需求，需要将A库的查询结果，写入到B库。

但是原来的springboot里面就只有A库，所以现在要加上B库。

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1.修改application.yaml的数据库连接

这个是原来的

现在改成

其实就是将datasource:xxx，改成了datasource:aku:xxx 然后【同级】加了一个bku:xxx。

还有要把url改成jdbc-url 。application的datasource下的url要换成jdbc-url。多数据的话必须换成这个

2.在resource的mapper里创建2个mapper文件夹

将原来默认的mapper下的，内容放到aku下，此时发现变灰，因为mapper路径被改了，下一步会重新配置映射

java代码包mapper的包里，也【创建】2个package

同样，把原来mapper的interface的java文件复制到aku里。

3.修改application.yaml的mybaits配置，重新配置映射

注意红色部分是我新加的，这样就重新映射上了

mybatis:
  mapper-locations: classpath:/mapper/**/*.xml
  configuration:
    map-underscore-to-camel-case: true

4.创建2个源连接，主库和从库的

以前是不需要配置的，因为会走默认配置，现在有2个了，你就得写2个，并且告诉他们对应的mapper是哪个。

随便找个文件夹创建一下，我在我自己的config里面创建下面2个程序

AkuDataSourceConfig

package com.example.demo.config;

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.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;
@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.aku", sqlSessionFactoryRef = "masterSqlSessionFactory")
public class AkuDataSourceConfig {

    @Primary
    @Bean("masterDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.master")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Primary
    @Bean("masterDataSourceTransactionManager")
    public DataSourceTransactionManager masterDataSourceTransactionManager(@Qualifier("masterDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Primary
    @Bean("masterSqlSessionFactory")
    public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource);
        Resource[] resources = new PathMatchingResourcePatternResolver().getResources("classpath:mapper/aku/*.xml");
        sqlSessionFactory.setMapperLocations(resources);

        return sqlSessionFactory.getObject();
    }

}

只用注意这3个地方改一下，标红的，分别对应的是interface,mapper.xml还有application.yaml

@MapperScan(basePackages = "com.example.demo.mapper.aku", sqlSessionFactoryRef = "masterSqlSessionFactory")

PathMatchingResourcePatternResolver().getResources("classpath:mapper/aku/*.xml");

@ConfigurationProperties(prefix = "spring.datasource.aku")

BkuDataSourceConfig

package com.example.demo.config;

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.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.example.demo.mapper.bku", sqlSessionFactoryRef = "slaveSqlSessionFactory")
public class BkuDataSourceConfig {

    @Bean("slaveDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.slave")
    public DataSource slaveDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean("slaveDataSourceTransactionManager")
    public DataSourceTransactionManager slaveDataSourceTransactionManager(@Qualifier("slaveDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean("slaveSqlSessionFactory")
    public SqlSessionFactory slaveSqlSessionFactory(@Qualifier("slaveDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource);
        Resource[] resources = new PathMatchingResourcePatternResolver().getResources("classpath:mapper/bku/*.xml");
        sqlSessionFactory.setMapperLocations(resources);

        return sqlSessionFactory.getObject();
    }


}

b库复制这段代码后，需要改的也是类似a库标红的地方。

5.启动测试

成功

用的时候导入不同的mapper，就可以了。

参考：Spring Boot整合MyBatis配置多数据源-CSDN博客