SpringBoot超详细讲解多数据源集成

时间:2022-12-26

一、多数据源使用场景与弊端

1.场景

  • 业务系统跨数据库
  • 数据转存(这个现在太low了,应该高级点都不用)
  • 系统集成

2.弊端

  • 跨库业务事务问题
  • service、dao不能重复注入数据源

二、使用步骤

1.引入库

<!-- 多数据源支持 -->
    <dependency>
      <groupId>com.baomidou</groupId>
      <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
      <version>3.3.6</version>
    </dependency>

2.多数据源配置文件

#数据源配置
spring:
  application:
    name: olap
  datasource:
    dynamic:
      primary: target
    target:
      jdbc-url: jdbc:mysql://192.168.1.101:15051/db1?useUnicode=true&characterEncoding=utf8&useSSL=true&allowPublicKeyRetrieval=true&serverTimezone=GMT%2B8
      username: root
      password: 123
      driver-class-name: com.mysql.jdbc.Driver
    source1:
      jdbc-url: jdbc:mysql://192.168.102:15052/db2?useUnicode=true&characterEncoding=utf8&useSSL=true&allowPublicKeyRetrieval=true&serverTimezone=GMT%2B8
      username: admin
      password: 456
      driver-class-name: com.mysql.jdbc.Driver

3.多数据源配置类

数据源1

import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import javax.sql.DataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
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 org.springframework.transaction.PlatformTransactionManager;
@Configuration
@MapperScan(basePackages = "com.easylinkin.dc.mapper.source1", sqlSessionFactoryRef = "source1SqlSessionFactory")
public class Source1DataSourceConfig {
  // mapper.xml所在地址
  private static final String MAPPER_LOCATION = "classpath*:mapper/business/source1/*.xml";
  /**
   * 数据源
   */
  @Bean(name = "source1DataSource")
  @ConfigurationProperties(prefix = "spring.datasource.source1")
  public DataSource dataSource() {
    DataSource build = DataSourceBuilder.create().build();
    return build;
  }
  /**
   * 事务管理器
   */
  @Bean(name = "source1TransactionManager")
  public PlatformTransactionManager dataSourceTransactionManager(
      @Qualifier("source1DataSource") DataSource dataSource) {
    return new DataSourceTransactionManager(dataSource);
  }
  /**
   * session工厂
   */
  @Bean(name = "source1SqlSessionFactory")
  public SqlSessionFactory sqlSessionFactory(@Qualifier("source1DataSource") DataSource dataSource)
      throws Exception {
  /*  final SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
    sessionFactoryBean.setDataSource(dataSource);
    sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(
        Source1DataSourceConfig.MAPPER_LOCATION));*/
    //不使用下面这个无法使用mybatis-plus提供的BaseMapper中的方法,需要增加mybatis-plus 的拓展依赖
    MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();
    bean.setDataSource(dataSource);
    //不在这里注入分页插件,会失效
    //bean.setPlugins(new PaginationInterceptor[]{new PaginationInterceptor()});
    return bean.getObject();
  }
}

数据源2

import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import javax.sql.DataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
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 org.springframework.transaction.PlatformTransactionManager;
@Configuration
@MapperScan(basePackages = "com.easylinkin.dc.mapper.target", sqlSessionFactoryRef = "targetSqlSessionFactory")
public class TargetDataSourceConfig {
  // mapper.xml所在地址
  private static final String MAPPER_LOCATION = "classpath*:mapper/business/target/*.xml";
  /**
   * 主数据源,Primary注解必须增加,它表示该数据源为默认数据源 项目中还可能存在其他的数据源,如获取时不指定名称,则默认获取这个数据源,如果不添加,则启动时候回报错
   */
  @Primary
  @Bean(name = "targetDataSource")
  @ConfigurationProperties(prefix = "spring.datasource.target")
  public DataSource dataSource() {
    DataSource build = DataSourceBuilder.create().build();
    return build;
  }
  /**
   * 事务管理器,Primary注解作用同上
   */
  @Bean(name = "masterTransactionManager")
  @Primary
  public PlatformTransactionManager dataSourceTransactionManager(
      @Qualifier("targetDataSource") DataSource dataSource) {
    return new DataSourceTransactionManager(dataSource);
  }
  /**
   * session工厂,Primary注解作用同上
   */
  @Bean(name = "targetSqlSessionFactory")
  @Primary
  public SqlSessionFactory sqlSessionFactory(@Qualifier("targetDataSource") DataSource dataSource)
      throws Exception {
    /*final SqlSessionFactoryBean sessionFactoryBean = new SqlSessionFactoryBean();
    sessionFactoryBean.setDataSource(dataSource);
    sessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(
        TargetDataSourceConfig.MAPPER_LOCATION));
    return sessionFactoryBean.getObject();*/
    //不使用下面这个无法使用mybatis-plus提供的BaseMapper中的方法,需要增加mybatis-plus 的拓展依赖
    MybatisSqlSessionFactoryBean bean = new MybatisSqlSessionFactoryBean();
    bean.setDataSource(dataSource);
    //不在这里注入分页插件,会失效
    //bean.setPlugins(new PaginationInterceptor[]{new PaginationInterceptor()});
    return bean.getObject();
  }
}
  • 注意dao一定要在@MapperScan注解设置的包下
  • 注意xml文件要在MAPPER_LOCATION=的路径下
  • springBoot启动类不要再用@MapperScan注解
  • 其他注意配置类的SqlSessionFactory 方法,看注释

4.使用

import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.easylinkin.dc.common.exceptions.BusinessException;
import com.easylinkin.dc.common.utils.io.OutputStreamUtil;
import com.easylinkin.dc.mapper.source1.FkRegisterVisitorMapper;
import com.easylinkin.dc.business.visitor.entity.FkRegisterVisitor;
import com.easylinkin.dc.business.visitor.entity.vo.FkRegisterVisitorVo;
import com.easylinkin.dc.business.visitor.service.FkRegisterVisitorService;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.Assert;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
/**
 * FkRegisterVisitor表服务实现类
 *
 * @author CodeGenerator
 * @date 2022/05/16
 */
@DS("source1")
@Slf4j
@Service("fkRegisterVisitorService")
public class FkRegisterVisitorServiceImpl extends ServiceImpl
    <FkRegisterVisitorMapper, FkRegisterVisitor> implements FkRegisterVisitorService {
    }

注意是在service的实现类上用@DS(“数据源名称”)注解,数据源名称与配置文件里的datasource下的一致。

注意dao不能再用@DS注解,否在报错

总结

我也是一个怕麻烦的人,所以能有简单的办法,我绝对不用复杂的,多数据源集成就是这么简单,也没啥好总结的,就提醒下:

跨数据源的业务接口要注意事务

@Transactional不生效

其实也有动态切换数据源的方法,我觉得没必要,规规矩矩用service,别把自己整糊了。

好就简单写道这里,up!

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