springboot mybatis 配置多數據源

1、在application.properties添加數據源配置

# 配置多數據源
spring.datasource.db1.url=jdbc:mysql://127.0.0.1:3306/test1
spring.datasource.db1.username=root
spring.datasource.db1.password=admin
# 使用druid數據源
spring.datasource.db1.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.db1.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.db1.max-idle=10
spring.datasource.db1.max-wait=10000
spring.datasource.db1.min-idle=5
spring.datasource.db1.initial-size=5

# 第二個數據庫
spring.datasource.db2.url=jdbc:mysql://127.0.0.1:3306/test2
spring.datasource.db2.username=root
spring.datasource.db2.password=admin
spring.datasource.db2.driver-class-name=com.mysql.jdbc.Driver

2、建立數據源配置文件

   設置第一個爲默認數據源，使用 @Primary 註解，多個數據源必須設置一個

package com.test.spike.datasources.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
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 org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.test.spike.dao", sqlSessionFactoryRef = "db1SqlSessionFactory")
public class DataSourceConfig1 {

    @Bean(name="db1DataSource")
    // 默認數據源
    @Primary
    // 讀取配置文件
    @ConfigurationProperties(prefix="spring.datasource.db1")
    public DataSource getDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name="db1SqlSessionFactory")
    @Primary
    // @Qualifier表示查找Spring容器中名字爲test1DataSource的對象
    public SqlSessionFactory db1SqlSessionFactory(@Qualifier("db1DataSource") DataSource datasource) throws Exception {

        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(datasource);
        // 設置mybatis的xml所在位置
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:com/test/spike/dao/mapper/*.xml"));
        return bean.getObject();
    }

    @Bean(name="db1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate db1SqlSessionTemplate(@Qualifier("db1SqlSessionFactory") SqlSessionFactory sessionfactory) {

        return new SqlSessionTemplate(sessionfactory);
    }

}

  第二個數據源

package com.test.spike.datasources.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.test.spike.db2", sqlSessionFactoryRef = "db2SqlSessionFactory")
public class DataSourceConfig2 {

    @Bean(name="db2DataSource")
    // 讀取配置文件
    @ConfigurationProperties(prefix="spring.datasource.db2")
    public DataSource getDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name="db2SqlSessionFactory")
    // @Qualifier表示查找Spring容器中名字爲test1DataSource的對象
    public SqlSessionFactory db2SqlSessionFactory(@Qualifier("db2DataSource") DataSource datasource) throws Exception {

        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(datasource);
        // 設置mybatis的xml所在位置
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:com/test/spike/db2/*.xml"));
        return bean.getObject();
    }

    @Bean(name="db2SqlSessionTemplate")
    public SqlSessionTemplate db2SqlSessionTemplate(@Qualifier("db2SqlSessionFactory") SqlSessionFactory sessionfactory) {

        return new SqlSessionTemplate(sessionfactory);
    }

}

注意：使用此方法解決多數據源，dao層代碼不能嵌套，嵌套後，默認數據源訪問正常，其他數據源訪問會報

         invalid bound statement (not found)

        經過一番折騰，參考各種文檔的解釋，最後找到了一種解決辦法。因爲將dao和mybatis的映射文件都放在了嵌套的目錄裏，所以在spring掃描的時候，記錄了首次掃描到dao的方法，然後使用首次掃描到dao的方法，調用其他路徑的映射文件時，就會提示無法找到映射文件的方法。

        解決辦法就是將不同的數據源dao層文件進行歸類存放，各自的數據庫配置放各自的目錄

目錄結構