spring boot 动态数据源

布满荆棘的人生 2022-05-11 11:22 196阅读 0赞

由于项目中要用到spring boot结合mybatis做一个动态的数据源，所以自己做了一个，也踩了很多坑，这里把成果分享出来。如果是1.x的springboot版本可以看前面的，如果是2.x版本的可以看后面的，2.x版本的更简单方便。

## 一、Springboot + Mybatis 多数据源配置 ##

### 1.Springboot.yml配置文件 ###

server:
      port: 9281
    #spring:
    #  profiles:
    #    active: dev
    #数据库1
    datasource1:
      url: jdbc:mysql://localhost:3306/ios666_history?useSSL=false&useUnicode=true
      username: root
      password:
      driver-class-name: com.mysql.jdbc.Driver
    #数据库2
    datasource2:
      url: jdbc:mysql://localhost:3306/av8d?useSSL=false&useUnicode=true
      username: root
      password:
      driver-class-name: com.mysql.jdbc.Driver

### 2.SpringbootApplication 禁止加载自身对DataSource的扫描 ###

@SpringBootApplication(exclude = {
            DataSourceAutoConfiguration.class
    })
    public class DatasourceApplication {
    	public static void main(String[] args) {
    		SpringApplication.run(DatasourceApplication.class, args);
    	}
    }

### DataSourceConfig 对 Springboot.yml 读取 ###

@Configuration
    public class DataSourceConfig {
        @Bean(name = "dbOneDataSource")
        @Primary
        @ConfigurationProperties(prefix = "datasource1") // application.yml 中对应属性的前缀
        public DataSource dbOneDataSource() {
            return DataSourceBuilder.create().build();
        }
        @Bean(name = "dbTwoDataSource")
        @ConfigurationProperties(prefix = "datasource2") // application.yml 中对应属性的前缀
        public DataSource dbTwoDataSource() {
            return DataSourceBuilder.create().build();
        }
    }

这里创建了2个`Bean`，由`dbOneDataSource` 和 `dbTwoDataSource` 读取并创建数据源。

## 二、数据源的创建  ##

如果有多个就直接创建多个，下面说说 `SqlSessionFactory && SqlSessionTemplate` 创建 。为了方便管理，我用内部类去解决。

package com.sojson.datasource.config;
 import lombok.extern.slf4j.Slf4j;
 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.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import javax.annotation.Resource;
 import javax.sql.DataSource;
 /**
 *
 * 开发公司：SOJSON在线工具 
 * 版权所有：© www.sojson.com
 * 博客地址：http://www.sojson.com/blog/ 
 * 
 * 说明： 
 * 
 * 如果有多个就直接创建多个，SqlSessionFactory && SqlSessionTemplate 创建
 * 
 *
 * 区分　责任人　日期　　　　 
 * 创建　周柏成　 2018年05月01日22:33:18 　 
 *
 * @author zhou-baicheng
 * @email so@sojson.com
 * @version 1.0 
 *
 */
 @Slf4j
 public class MybatisConfig {
 /**
 * 第一个数据库 SqlSessionFactory && SqlSessionTemplate 创建
 */
 @Configuration
 @MapperScan(basePackages = {"com.sojson.datasource.one.mapper"},
 sqlSessionFactoryRef = "sqlSessionFactoryOne",
 sqlSessionTemplateRef = "sqlSessionTemplateOne")
 public static class DBOne{
 @Resource
 DataSource dbOneDataSource;
 @Bean
 public SqlSessionFactory sqlSessionFactoryOne() throws Exception {
 log.info("sqlSessionFactoryOne 创建成功。");
 SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
 factoryBean.setDataSource(dbOneDataSource);
 factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/one/*.xml"));
 return factoryBean.getObject();
 }
 @Bean
 public SqlSessionTemplate sqlSessionTemplateOne() throws Exception {
 SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactoryOne()); // 使用上面配置的Factory
 return template;
 }
 }
 /**
 * 第二个数据库 SqlSessionFactory && SqlSessionTemplate 创建
 */
 @Configuration
 @MapperScan(basePackages = {"com.sojson.datasource.two.mapper"},
 sqlSessionFactoryRef = "sqlSessionFactoryTwo",
 sqlSessionTemplateRef ="sqlSessionTemplateTwo" )
 public static class DBTwo{
 @Resource
 DataSource dbTwoDataSource;
 @Bean
 public SqlSessionFactory sqlSessionFactoryTwo() throws Exception {
 log.info("sqlSessionFactoryTwo 创建成功。");
 SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
 factoryBean.setDataSource(dbTwoDataSource);
 、、
 factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/two/*.xml"));
 return factoryBean.getObject();
 }
 @Bean
 public SqlSessionTemplate sqlSessionTemplateTwo() throws Exception {
 SqlSessionTemplate template = new SqlSessionTemplate(sqlSessionFactoryTwo()); // 使用上面配置的Factory
 return template;
 }
 }
 }

这里要详细说明的一下，因为创建了2套的`SqlSessionFactory && SqlSessionTemplate`，那怎么来区分或者说怎么分配数据源呢？

通过注释 ：`basePackages = {"com.sojson.datasource.one.mapper"}`来定义第一个数据源 `SqlSessionFactory` 的`mapper`目录。

通过注释 ：`basePackages = {"com.sojson.datasource.two.mapper"}`来定义第二个数据源 `SqlSessionFactory` 的`mapper`目录。

如果在运行中出现缺少 org/springframework/boot/bind/RelaxedPropertyResolver 证明你使用的是2.x版本，这里直接使用下面的方法，很简单。

第一步写好配置文件

server:
      port: 8080
    
    spring:  
      datasource:
        master:
          driver-class-name: com.mysql.jdbc.Driver
          url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
          username: root
          password: 123456
        slaver:
          driver-class-name: com.mysql.jdbc.Driver
          url: jdbc:mysql://127.0.0.1:3306/dev?useUnicode=true&characterEncoding=utf-8&useSSL=false
          username: root
          password: 123456

第二步 写好config配置类

1、主库数据源配置

@Configuration
    @MapperScan(basePackages = "com.somta.springboot.dao.master", sqlSessionTemplateRef  = "masterSqlSessionTemplate")
    public class MasterDataSourceConfiguration {
    
        @Value("${spring.datasource.master.driver-class-name}")
        private String driverClassName;
    
        @Value("${spring.datasource.master.url}")
        private String url;
    
        @Value("${spring.datasource.master.username}")
        private String username;
    
        @Value("${spring.datasource.master.password}")
        private String password;
    
        @Bean(name = "masterDataSource")
        @Primary
        public DataSource dataSource() {
            DruidDataSource dataSource = new DruidDataSource();
            dataSource.setDriverClassName(this.driverClassName);
            dataSource.setUrl(this.url);
            dataSource.setUsername(this.username);
            dataSource.setPassword(this.password);
            return dataSource;
        }
    
        @Bean(name = "masterSqlSessionFactory")
        @Primary
        public SqlSessionFactory sqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
            SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
            bean.setDataSource(dataSource);
            bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mybatis/master/**/Mysql_*Mapper.xml"));
            return bean.getObject();
        }
    
        @Bean(name = "masterTransactionManager")
        @Primary
        public DataSourceTransactionManager transactionManager(@Qualifier("masterDataSource") DataSource dataSource) {
            return new DataSourceTransactionManager(dataSource);
        }
    
        @Bean(name = "masterSqlSessionTemplate")
        @Primary
        public SqlSessionTemplate sqlSessionTemplate(@Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
            return new SqlSessionTemplate(sqlSessionFactory);
        }
    
    }

2、从库的数据源配置信息

@Configuration
    @MapperScan(basePackages = "com.somta.springboot.dao.slaver", sqlSessionTemplateRef  = "slaverSqlSessionTemplate")
    public class SlaverDataSourceConfiguration {
    
        @Value("${spring.datasource.slaver.driver-class-name}")
        private String driverClassName;
    
        @Value("${spring.datasource.slaver.url}")
        private String url;
    
        @Value("${spring.datasource.slaver.username}")
        private String username;
    
        @Value("${spring.datasource.slaver.password}")
        private String password;
    
    
        @Bean(name = "slaverDataSource")
        public DataSource dataSource() {
            DruidDataSource dataSource = new DruidDataSource();
            dataSource.setDriverClassName(this.driverClassName);
            dataSource.setUrl(this.url);
            dataSource.setUsername(this.username);
            dataSource.setPassword(this.password);
            return dataSource;
        }
    
        @Bean(name = "slaverSqlSessionFactory")
        public SqlSessionFactory sqlSessionFactory(@Qualifier("slaverDataSource") DataSource dataSource) throws Exception {
            SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
            bean.setDataSource(dataSource);
            bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mybatis/slaver/**/Mysql_*Mapper.xml"));
            return bean.getObject();
        }
    
        @Bean(name = "slaverTransactionManager")
        public DataSourceTransactionManager transactionManager(@Qualifier("slaverDataSource") DataSource dataSource) {
            return new DataSourceTransactionManager(dataSource);
        }
    
        @Bean(name = "slaverSqlSessionTemplate")
        public SqlSessionTemplate sqlSessionTemplate(@Qualifier("slaverSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
            return new SqlSessionTemplate(sqlSessionFactory);
        }
    
    }

注意在配置数据源的信息时，一定要通过@Primary配置一个主库，对于数据库配置部分与普通的数据源配置没有差异，新建一个DataSource，在创建一个SqlSessionTemplate，最后创建一个SqlSessionTemplate，分别以此注入即可，@MapperScan注解的扫描路径要分别对于相应的dao层