Springboot2.x+mybatis多數據源（MySQL+Oracle）集成

  背景：最近項目需求需要同時查詢MySQL和Oracle的數據，項目已經上線，總結一下，以備後續查看（該文檔並不是完整的項目）。

項目基於gradle管理的標準的Web MVC架構：

build.gradle

group 'com.data.mult'
version '1.0-SNAPSHOT'

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'application'

mainClassName = 'com.data.mult.MultDataSourceApplication'
[compileJava, compileTestJava]*.options*.encoding = 'UTF-8'

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    mavenLocal()
    maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
    maven { url "http://repo.maven.apache.org/maven2" }
    mavenCentral()
}

dependencies {
    compile group: 'com.alibaba', name: 'fastjson', version: '1.2.60'
    compile('org.springframework.boot:spring-boot-starter-web:2.1.5.RELEASE') {
        exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
    }
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-log4j2', version: '2.1.5.RELEASE'
    compile('org.mybatis.spring.boot:mybatis-spring-boot-starter:2.0.1') {
        exclude group: 'org.springframework.boot', module: 'spring-boot-starter'
    }
    compile group: 'com.oracle.jdbc', name: 'ojdbc6', version: '11.2.0.4.0'
    compile group: "mysql", name: "mysql-connector-java", version: "8.0.11"
}

application.properties

#mybatis的配置文件路徑
mybatis.config-locations=classpath:mybatis/mybatis-config.xml
#mybatis的mapper映射文件地址路徑
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
#mysql庫1的配置
spring.datasource.primary.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.primary.jdbc-url=jdbc:mysql://localhost:3306/lwca?characterEncoding=utf8
spring.datasource.primary.username=root
spring.datasource.primary.password=123456


#oracle庫的配置
spring.datasource.third.driverClassName=oracle.jdbc.OracleDriver
spring.datasource.third.jdbc-url=jdbc:oracle:thin:@localhost:1521:orcl
spring.datasource.third.username=root
spring.datasource.third.password=123456

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 全局參數 -->
    <settings>
        <!-- 使全局的映射器啓用或禁用緩存。 -->
        <setting name="cacheEnabled" value="true"/>
        <!-- 全局啓用或禁用延遲加載。當禁用時，所有關聯對象都會即時加載。 -->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!-- 當啓用時，有延遲加載屬性的對象在被調用時將會完全加載任意屬性。否則，每種屬性將會按需要加載。 -->
        <setting name="aggressiveLazyLoading" value="true"/>
        <!-- 是否允許單條sql 返回多個數據集  (取決於驅動的兼容性) default:true -->
        <setting name="multipleResultSetsEnabled" value="true"/>
        <!-- 是否可以使用列的別名 (取決於驅動的兼容性) default:true -->
        <setting name="useColumnLabel" value="true"/>
        <!-- 允許JDBC 生成主鍵。需要驅動器支持。如果設爲了true，這個設置將強制使用被生成的主鍵，有一些驅動器不兼容不過仍然可以執行。  default:false  -->
        <setting name="useGeneratedKeys" value="true"/>
        <!-- 指定 MyBatis 如何自動映射 數據基表的列 NONE：不隱射　PARTIAL:部分  FULL:全部  -->
        <setting name="autoMappingBehavior" value="PARTIAL"/>
        <!-- 這是默認的執行類型  （SIMPLE: 簡單； REUSE: 執行器可能重複使用prepared statements語句；BATCH: 執行器可以重複執行語句和批量更新）  -->
        <setting name="defaultExecutorType" value="SIMPLE"/>
        <!-- 使用駝峯命名法轉換字段。 -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
        <!-- 設置本地緩存範圍 session:就會有數據的共享  statement:語句範圍 (這樣就不會有數據的共享 ) defalut:session -->
        <setting name="localCacheScope" value="SESSION"/>
        <!-- 設置但JDBC類型爲空時,某些驅動程序 要指定值,default:OTHER，插入空值時不需要指定類型 -->
        <setting name="jdbcTypeForNull" value="NULL"/>
    </settings>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer"/>
        <typeAlias alias="Long" type="java.lang.Long"/>
        <typeAlias alias="HashMap" type="java.util.HashMap"/>
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap"/>
        <typeAlias alias="ArrayList" type="java.util.ArrayList"/>
        <typeAlias alias="LinkedList" type="java.util.LinkedList"/>
    </typeAliases>
</configuration>

DataSource1Config.java

package com.data.mult.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.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.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.htiiot.htdata.dao.mapper1", sqlSessionTemplateRef  = "primarySqlSessionTemplate")
public class DataSource1Config {

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

    @Bean(name = "primarySqlSessionFactory")
    @Primary
    public SqlSessionFactory primarySqlSessionFactory(@Qualifier("primaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/map1/*"));
        return bean.getObject();
    }

    @Bean(name = "primaryTransactionManager")
    @Primary
    public DataSourceTransactionManager primaryTransactionManager(@Qualifier("primaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "primarySqlSessionTemplate")
    @Primary
    public SqlSessionTemplate primarySqlSessionTemplate(@Qualifier("primarySqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

DataSource3Config.java

package com.data.mult.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.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.htiiot.htdata.dao.mapper3", sqlSessionTemplateRef  = "thirdSqlSessionTemplate")
public class DataSource3Config {

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

    @Bean(name = "thirdSqlSessionFactory")
    public SqlSessionFactory thirdSqlSessionFactory(@Qualifier("thirdDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/map3/*"));
        return bean.getObject();
    }

    @Bean(name = "thirdTransactionManager")
    public DataSourceTransactionManager thirdTransactionManager(@Qualifier("thirdDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "thirdSqlSessionTemplate")
    public SqlSessionTemplate thirdSqlSessionTemplate(@Qualifier("thirdSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

這裏有幾個點需要分開寫：

1.配置application.properties中的配置前綴字符串

2.配置掃描mapperScan掃描的接口包路徑

3.配置mapper.xml所在的目錄。

總結：其他的跟單數據源的流程一樣，該怎麼寫就怎麼寫。