Springboot2動態切換Mysql和Sqlserver數據庫

最近項目中需要切換數據庫，查找了一些資料，也做了一些實驗，實現了動態切換多數據源的數據庫，做法如下：
1、依賴兩種數據庫的數據源

        <!-- mysql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!-- sqlserver -->
        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>sqljdbc4</artifactId>
            <version>4.0</version>
        </dependency>

2、在yml中追加多個數據源

spring:
  datasource:
    sqlserver:
      jdbc-url: jdbc:sqlserver://xxx.xxx.xx.xxx:1433;DatabaseName=RFDB
      driver-class-name: com.microsoft.sqlserver.jdbc.SQLServerDriver
      username: sa
      password: 'xxx'
    mysql:
      driver-class-name: com.mysql.cj.jdbc.Driver
      jdbc-url: jdbc:mysql://xxx.xxx.xx.xxx:3306/jndjplatform?characterEncoding=utf8&serverTimezone=Hongkong
      username: root
      password: xxx

3、配置類的代碼

package com.jndj.platform.config.mybatisplus;

import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.jndj.platform.config.mybatisplus.custom.DataSourceEnum;
import com.jndj.platform.config.mybatisplus.custom.MultipleDataSource;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.type.JdbcType;
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 javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
 * @author yaohj
 * @date 2020/1/15
 */
@Configuration
@MapperScan({"com.jndj.platform.common.mapper","com.jndj.platform.*.*.mapper"})
public class MybatisPlusConfig {

    /**
     * mybatis-plus分頁插件<br>
     * 文檔：http://mp.baomidou.com<br>
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }

    /**
     * @author yangzh
     * 配置mysql datasource
     * @return
     */
    @Bean(name = "dataSourceMysql")
    @ConfigurationProperties(prefix = "spring.datasource.mysql")
    public DataSource dataSourceMysql() {
        return DataSourceBuilder.create().build() ;
    }

    /**
     * @author yangzh
     * 配置 sql server datasource
     * @return
     */
    @Bean(name = "dataSourceSqlServer")
    @ConfigurationProperties(prefix = "spring.datasource.sqlserver")
    public DataSource dataSourceSqlServer() {
        return DataSourceBuilder.create().build() ;
    }

    /**
     * 使用枚舉類 映射兩個datasource
     * @param mysql
     * @param sqlServer
     * @return
     */
    @Bean
    @Primary
    public DataSource multipleDataSource(@Qualifier("dataSourceMysql") DataSource mysql,
                                         @Qualifier("dataSourceSqlServer") DataSource sqlServer) {
        MultipleDataSource multipleDataSource = new MultipleDataSource() ;
        Map<Object, Object> targetDataSources = new HashMap<>() ;
        targetDataSources.put(DataSourceEnum.dataSourceMysql.getValue(), mysql) ;
        targetDataSources.put(DataSourceEnum.dataSourceSqlServer.getValue(), sqlServer) ;
        //添加數據源
        multipleDataSource.setTargetDataSources(targetDataSources) ;
        //設置默認數據源db1
        multipleDataSource.setDefaultTargetDataSource(mysql  );
        return multipleDataSource ;
    }

    @Bean("sqlSessionFactory")
    public MybatisSqlSessionFactoryBean sqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean() ;
        sqlSessionFactory.setDataSource(multipleDataSource(dataSourceMysql(), dataSourceSqlServer())) ;

        MybatisConfiguration configuration = new MybatisConfiguration() ;
        configuration.setJdbcTypeForNull(JdbcType.NULL) ;
        configuration.setMapUnderscoreToCamelCase(true) ;
        configuration.setCacheEnabled(false) ;
        sqlSessionFactory.setConfiguration(configuration) ;
        sqlSessionFactory.setPlugins(new Interceptor[]{ paginationInterceptor() });
        return sqlSessionFactory ;
    }
}

package com.jndj.platform.config.mybatisplus.custom;

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Component
@Slf4j
@Aspect
@Order(-1)
public class DataSourceAspect {

    /**
     * 設置切面範圍
     */
    @Pointcut("@within(com.jndj.platform.config.mybatisplus.custom.DataSource) || " +
            "@annotation(com.jndj.platform.config.mybatisplus.custom.DataSource)")
    public void pointCut(){}

    /**
     * 添加數據源上下文
     * @param dataSource
     */
    @Before("pointCut() && @annotation(dataSource)")
    public void doBefore(DataSource dataSource){
        DataSourceContextHolder.setDataSource(dataSource.value().getValue());
    }

    /**
     * 清除數據源上下文
     */
    @After("pointCut()")
    public void doAfter(){
        DataSourceContextHolder.clear();
    }
}

package com.jndj.platform.config.mybatisplus.custom;

/**
 *
 */
public class DataSourceContextHolder {

    private static final ThreadLocal<String> contextHolder = new InheritableThreadLocal<>() ;

    /**
     *  設置數據源
     * @param db
     */
    public static void setDataSource(String db){
        contextHolder.set(db) ;
    }

    /**
     * 取得當前數據源
     * @return
     */
    public static String getDataSource(){
        return contextHolder.get() ;
    }

    /**
     * 清除上下文數據
     */
    public static void clear(){
        contextHolder.remove() ;
    }
}

package com.jndj.platform.config.mybatisplus.custom;

/**
 * 枚舉類 用於切換數據庫
 */
public enum DataSourceEnum {
    /**
     * 數據庫1
     */
    dataSourceMysql("dataSourceMysql"),
    /**
     * 數據庫2
     */
    dataSourceSqlServer("dataSourceSqlServer");

    private String value ;

    DataSourceEnum(String value){
        this.value = value ;
    }

    public String getValue() {
        return value;
    }
}

package com.jndj.platform.config.mybatisplus.custom;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

/**
 * 自由切換datasource
 */
public class MultipleDataSource extends AbstractRoutingDataSource {

    /**
     * 重寫determineCurrentLookupKey()，通過DataSourceContextHolder 獲取數據源變量，用於當作lookupKey取出指定的數據源
     * determineCurrentLookupKey，該方法返回一個Object，一般是返回字符串
     *
     * @return
     */
    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.getDataSource();
    }
}

package com.jndj.platform.config.mybatisplus.custom;

import java.lang.annotation.*;

/**
 * 自定義的註解
 * 可以在 mapper 或者 service 中使用
 * 可以用於方法，也可以用於類
 *
 * 本註解用於切換數據庫 例 @DataSource("dataSourceMsql")
 */
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
    DataSourceEnum value() default DataSourceEnum.dataSourceMysql;
}

3、mapper中使用新定義的註解標籤就可以了

package com.jndj.platform.system.user.mapper;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.jndj.platform.common.mapper.BaseMapperEx;
import com.jndj.platform.config.mybatisplus.custom.DataSource;
import com.jndj.platform.config.mybatisplus.custom.DataSourceEnum;
import com.jndj.platform.system.user.entity.User;
import org.apache.ibatis.annotations.Select;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * @author yaohj
 * @date 2020/2/19
 */
@Repository
@DataSource(DataSourceEnum.dataSourceSqlServer)
public interface UserMapper extends BaseMapperEx<User> {
    /**
     *
     * @param page 翻頁對象，傳遞參數 Page 即自動分頁
     * @return
     */
    List<User> getUserList(User form, Page page);
}

4、想切換數據庫時，使用上面mapper中使用的@DataSource(DataSourceEnum.dataSourceSqlServer)進行切換就可以了