springboot 2.1.3 + mybatis + druid配置多数据源

在一些大型的项目中，通常会选择多数据库来满足一些业务需求，此处讲解使用springboot、mybatis和druid来配置多数据源

1、依赖配置

　　pom文件引入相关依赖

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>    

　　application文件加入多数据源配置

　　spring:
        datasource:
            type: com.alibaba.druid.pool.DruidDataSource
            driverClassName: com.mysql.cj.jdbc.Driver
            druid:
                # 主库数据源
                master:
                    url: jdbc:mysql://localhost:3306/springboot?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false
                    username: root
                    password: root
                # 从库数据源
                slave:
                    url: jdbc:mysql://ip:3306/springboot?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false
                    username: root
                    password: root
                # 初始连接数
                initial-size: 10
                # 最大连接池数量
                max-active: 100
                # 最小连接池数量
                min-idle: 10
                # 配置获取连接等待超时的时间
                max-wait: 60000
                # 打开PSCache，并且指定每个连接上PSCache的大小
                pool-prepared-statements: true
                max-pool-prepared-statement-per-connection-size: 20
                # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
                timeBetweenEvictionRunsMillis: 60000
                # 配置一个连接在池中最小生存的时间，单位是毫秒
                min-evictable-idle-time-millis: 300000
                validation-query: SELECT 1 FROM DUAL
                test-while-idle: true
                test-on-borrow: false
                test-on-return: false
                stat-view-servlet:
                    enabled: true
                    url-pattern: /monitor/druid/*
                filter:
                    stat:
                        log-slow-sql: true
                        slow-sql-millis: 1000
                        merge-sql: false
                    wall:
                        config:
                            multi-statement-allow: true
                            

2、添加主数据源和其他数据源配置

　　主数据源

@Configuration
//master mapper目录
@MapperScan(basePackages = {"com.example.springbootdruidmultsource.mapper.master"}, sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterDataSourcesConfig {

    private static final String MAPPER_LOCAL = "classpath:mybatis/master/*.xml";

    @ConfigurationProperties("spring.datasource.druid.master")
    @Primary
    @Bean(name = "masterDataSource")
    public DruidDataSource druidDataSource() {
        return new DruidDataSource();
    }

    @Bean(name = "masterTransactionManager")
    @Primary
    public DataSourceTransactionManager masterTransactionManager() {
        return new DataSourceTransactionManager(druidDataSource());
    }

    @Bean(name = "masterSqlSessionFactory")
    @Primary
    public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        final SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(MAPPER_LOCAL));
        return sessionFactoryBean.getObject();
    }
}

其中注解@Primary表示是主数据源

　　从数据源

@Configuration
@MapperScan(basePackages = {"com.example.springbootdruidmultsource.mapper.slave"}, sqlSessionFactoryRef = "slaveSqlSessionFactory")
public class SlaveDataSourcesConfig {

    private static final String MAPPER_LOCAL = "classpath:mybatis/slave/*.xml";

    @Bean(name = "slaveDataSource")
    @ConfigurationProperties("spring.datasource.druid.slave")
    public DruidDataSource druidDataSource() {
        return new DruidDataSource();
    }

　　 //其他数据源的事务管理器
    @Bean(name = "slaveTransactionManager")
    public DataSourceTransactionManager slaveTransactionManager() {
        return new DataSourceTransactionManager(druidDataSource());
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory slaveSqlSessionFactory(@Qualifier("slaveDataSource") DruidDataSource dataSource) throws Exception {
        final SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
        sessionFactoryBean.setDataSource(dataSource);
        sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(MAPPER_LOCAL));
        return sessionFactoryBean.getObject();
    }
}

其他的就是mybatis相关的一些内容，这里不赘述

3、事务管理

对主数据原来说，直接在注解

    @Override
    @Transactional
    public void update(SysUser sysUser) {
        sysUserMapper.update(sysUser);
        int i = 10 / 0;
    }

对其他数据源来说，需要加上配置的事务管理器

    @Override
    @Transactional(value = "slaveTransactionManager")
    public void update(User user) {
        userMapper.update(user);
        int i = 10 / 0;
    }

源码参照：Github