springboot —— 多数据源

本文主要介绍如何在一个springboot项目配置两个数据源（mysql和oracle）；

1、引进相关依赖

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!--oracle 驱动 -->
<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc6</artifactId>
    <version>11.1.0.7.0</version>
</dependency>

当ojdbc驱动包版本过低，会报如下图所示错误，即驱动jar与数据库版本不兼容：

2、于applicationContext.yml中配置数据源连接参数：

    Spring:
        datasource:
            base:
                 driver-class-name: com.mysql.jdbc.Driver
                 jdbc-url: ${base.db.url}
                 username: ${base.db.username}
                 password: ${base.db.password}
            oa:
                 driver-class-name: oracle.jdbc.driver.OracleDriver
                 jdbc-url: ${oa.db.urL}
                 username: ${oa.db.username}
                 password: ${oa.db.password}
            hikari:
                 max-lifetime: 60000
                 login-timeout: 5
                 validation-timeout: 3000
                 connection-timeout: 60000
                 idle-timeout: 60000

3、多数据源配置文件，读取对应连接参数

Package com.**.config;

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 javax.sql.DataSource;

public class MultiDataSourceConfig {

    @Bean (name = "primaryDataSource")
    @Qualifier("primaryDataSource")
    @Primary //定义主数据源
    @ConfigurationProperties (prefix = "spring.datasource.Base")
    public DataSource primaryDataSource () { return DataSourceBuilder.create().build (); }

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

}

3、主数据源配置，指定扫描对应mapper文件以及对应xml文件，在使用mapper包下的mapper文件时会自动使用对应sql会话

Package com.**.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.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframeworkcore.io.support.PathMatchingResourcePatternResolver;
import org.spr ingframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;

@Configuration
@MapperScan (basePackages = "com.**.mapper", sqlSessionTemplateRef = "primarySqlSessionTemplate")
public class SqlSessionTemplate1 {

    @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 (locationPattern: "classpath: mybatis/mapper/*. XmL"));
        return bean.getObject();
    }

    /**
     * 配置声明式事务管理器
     */
    @Bean (name = "primaryTransactionManager")
    @Primary
    public PlatformTransactionManager primaryTransactionManager  (@Qualifier("primaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager  (dataSource);
    }

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

4、第二数据源配置，指定扫描对应mapper文件以及对应xml文件，在使用mapper包下的mapper文件时会自动使用对应sql会话

Package com.**.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.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.secondary;
import org.springframeworkcore.io.support.PathMatchingResourcePatternResolver;
import org.spr ingframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import javax.sql.DataSource;

@Configuration
@MapperScan (basePackages = "com.**.oraclemapper", sqlSessionTemplateRef = "secondarySqlSessionTemplate")
public class SqlSessionTemplate2 {

    @Bean (name = "secondarySqlSessionFactory")
    public SqlSessionFactory secondarySqlSessionFactory  (@Qualifier("secondaryDataSource") DataSource dataSource)
            throws Exception{
        SqLSessionFactoryBean bean = new SqlSessionFactoryBean ();
        bean.setDataSource (dataSource);
        bean.setMapperLocations (new PathMatchingResourcePatternResolver().getResources (locationPattern: "classpath: mybatis/oraclemapper/*. XmL"));
        return bean.getObject();
    }

    /**
     * 配置声明式事务管理器
     */
    @Bean (name = "secondaryTransactionManager")
    public PlatformTransactionManager secondaryTransactionManager  (@Qualifier("secondaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager  (dataSource);
    }

    @Bean (name = "secondarySqlSessionTemplate")
    public SqlSessionTemplatel secondarySqlSessionTemplate(@Qualifier("secondarySqlSesionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplatel(sqlSessionFactory);
    }
}

至此，在service层可以像单数据源一样使用了。