springboot+druid+mybatis plus的多数

多数据源配置，在我们集成多个系统或者对接的时候经常会用到，结合springboot、druid提供了比较方便的集成方案。

思路：
1、yml中配置多个数据源信息
2、通过AOP切换不同数据源
3、配合mybatis plus使用

---

1、yml配置

spring:
  aop:
      proxy-target-class: true
      auto: true
  datasource:
    druid:
      db1:
        url: jdbc:mysql://localhost:3306/eboot
        username: root
        password: root
        driver-class-name: com.mysql.jdbc.Driver
        initialSize: 5
        minIdle: 5
        maxActive: 20
      db2:
        url: jdbc:oracle:thin:@192.168.136.222:ORCL
        username: sa
        password: sa123456
        driver-class-name: oracle.jdbc.OracleDriver
        initialSize: 5
        minIdle: 5
        maxActive: 20
      db3:
        url: jdbc:oracle:thin:@192.168.136.223:ORCL
        username: sb
        password: sb123456
        driver-class-name: oracle.jdbc.OracleDriver
        initialSize: 5
        minIdle: 5
        maxActive: 20

2、启动加载多个数据源

下面mybatis plus的全局配置被注掉了，因为同样可以在yml中配置也可以

package com.df.openapi.config;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import com.baomidou.mybatisplus.MybatisConfiguration;
import com.baomidou.mybatisplus.entity.GlobalConfiguration;
import com.baomidou.mybatisplus.mapper.LogicSqlInjector;
import com.baomidou.mybatisplus.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.spring.MybatisSqlSessionFactoryBean;
import com.df.openapi.config.db.DBTypeEnum;
import com.df.openapi.config.db.DynamicDataSource;
import com.df.openapi.config.db.MyMetaObjectHandler;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.session.SqlSessionFactory;
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.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;

/**
 * @author 小尘哥
 */
@EnableTransactionManagement
@Configuration
@MapperScan("com.df.openapi.**.mapper.db*")
public class MybatisPlusConfig {

    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        paginationInterceptor.setLocalPage(true);
        return paginationInterceptor;
    }

    @Bean(name = "db1")
    @ConfigurationProperties(prefix = "spring.datasource.druid.db1")
    public DataSource db1() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean(name = "db2")
    @ConfigurationProperties(prefix = "spring.datasource.druid.db2")
    public DataSource db2() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean(name = "db3")
    @ConfigurationProperties(prefix = "spring.datasource.druid.db3")
    public DataSource db3() {
        return DruidDataSourceBuilder.create().build();
    }

    /**
     * 动态数据源配置
     *
     * @return
     */
    @Bean
    @Primary
    public DataSource multipleDataSource(@Qualifier("db1") DataSource db1,
                                         @Qualifier("db2") DataSource db2,
                                         @Qualifier("db3") DataSource db3) {
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DBTypeEnum.db1.getValue(), db1);
        targetDataSources.put(DBTypeEnum.db2.getValue(), db2);
        targetDataSources.put(DBTypeEnum.db3.getValue(), db3);
        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(db2);
        return dynamicDataSource;
    }

    @Bean("sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(multipleDataSource(db1(), db2(),db3()));

        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setCacheEnabled(false);
        sqlSessionFactory.setConfiguration(configuration);
        //PerformanceInterceptor(),OptimisticLockerInterceptor()
        //添加分页功能
        sqlSessionFactory.setPlugins(new Interceptor[]{
                paginationInterceptor()
        });
//        sqlSessionFactory.setGlobalConfig(globalConfiguration());
        return sqlSessionFactory.getObject();
    }

 /*   @Bean
    public GlobalConfiguration globalConfiguration() {
        GlobalConfiguration conf = new GlobalConfiguration(new LogicSqlInjector());
        conf.setLogicDeleteValue("-1");
        conf.setLogicNotDeleteValue("1");
        conf.setIdType(0);
        conf.setMetaObjectHandler(new MyMetaObjectHandler());
        conf.setDbColumnUnderline(true);
        conf.setRefresh(true);
        return conf;
    }*/
}

3、DBType枚举类

package com.df.openapi.config.db;

public enum DBTypeEnum {

    db1("db1"), db2("db2"), db3("db3");
    private String value;

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

    public String getValue() {
        return value;
    }
}

4、动态数据源决策

package com.df.openapi.config.db;

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

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return  DbContextHolder.getDbType();
    }
}

5、设置、获取数据源

package com.df.openapi.config.db;

public class DbContextHolder {

    private static final ThreadLocal contextHolder = new ThreadLocal<>();
    /**
     * 设置数据源
     * @param dbTypeEnum
     */
    public static void setDbType(DBTypeEnum dbTypeEnum) {
        contextHolder.set(dbTypeEnum.getValue());
    }

    /**
     * 取得当前数据源
     * @return
     */
    public static String getDbType() {
        return (String) contextHolder.get();
    }

    /**
     * 清除上下文数据
     */
    public static void clearDbType() {
        contextHolder.remove();
    }
}

6、AOP实现的数据源切换

@Order设置的足够小是为了让他先执行

package com.df.openapi.config.db;

import lombok.extern.slf4j.Slf4j;
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;

/**
 * @author 迪富
 */
@Component
@Order(value = -100)
@Slf4j
@Aspect
public class DataSourceSwitchAspect {

    @Pointcut("execution(* com.df.openapi.*.mapper.db1..*.*(..))")
    private void db1Aspect() {
    }

    @Pointcut("execution(* com.df.openapi.*.mapper.db2..*.*(..))")
    private void db2Aspect() {
    }

    @Pointcut("execution(* com.df.openapi.*.mapper.db3..*.*(..))")
    private void db3Aspect() {
    }

    @Before("db1Aspect()")
    public void db1() {
        log.info("切换到db1 数据源...");
        DbContextHolder.setDbType(DBTypeEnum.db1);
    }

    @Before("db2Aspect()")
    public void db2() {
        log.info("切换到db2 数据源...");
        DbContextHolder.setDbType(DBTypeEnum.db2);
    }

    @Before("db3Aspect()")
    public void db3() {
        log.info("切换到db3 数据源...");
        DbContextHolder.setDbType(DBTypeEnum.db3);
    }
}

7、mapper层结构

根据dbx的实现数据源切换.png

8、写一个service测试一下

可以看到下面的两个Mapper分别来自db1和db2

package com.df.openapi.system.service.impl;

import com.df.openapi.system.entity.PtDict;
import com.df.openapi.system.entity.SysDict;
import com.df.openapi.system.mapper.db1.PtDictMapper;
import com.df.openapi.system.mapper.db2.SysDictMapper;
import com.df.openapi.system.service.IDictService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class DictServiceImpl implements IDictService {

    @Resource
    private PtDictMapper ptDictMapper;

    @Resource
    private SysDictMapper sysDictMapper;


    @Override
    public void getById(String id) {
        PtDict dict = ptDictMapper.selectById("2bf6257fc8fe483c84c1ad7e89d632f6");
        SysDict sysDict = sysDictMapper.getById("49");
        System.out.println("123");
    }
}

9、简单的单元测试

@RunWith(SpringRunner.class)
@SpringBootTest
public class OpenApiApplicationTests {

    @Autowired
    private IDictService dictService;

    @Test
    public void contextLoads() {
    }

    @Test
    public void test() {
        dictService.getById("1");
    }
}

10、测试结果

取到两个数据库的数据.png

参考上面的方法，可以随意配置三四五六七八九十个数据源都没问题，有问题欢迎随时来撩！