SpringBoot2.x系列教程48--多数据源配置之AOP动态切换数据源

作者：一一哥

在上一节中，我通过分包的方式实现了多数据源的配置，接下来我通过AOP切面的方式，带领大家实现第二种多数据源配置方式，该方式是在前面案例的基础上进行编写的。

一. 实现过程

1. 创建web项目

我们按照之前的经验，创建一个web程序，并将之改造成Spring Boot项目，具体过程略。

2. 添加依赖包

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>druid</artifactId>
   <version>1.1.10</version>
</dependency>

3. 创建application.yml配置文件

在该配置文件中，要进行两个数据库的配置，本案例中我们使用默认的HikariDataSource数据源。

spring:
  main:
    allow-bean-definition-overriding: true
  datasource:
    ds1:
      url: jdbc:mysql://localhost:3306/db1?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
      username: root
      password: syc
      driverClassName: com.mysql.jdbc.Driver
    ds2:
      url: jdbc:mysql://localhost:3306/db4?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
      username: root
      password: syc
      driverClassName: com.mysql.jdbc.Driver
    type: com.zaxxer.hikari.HikariDataSource
#    type: com.alibaba.druid.pool.DruidDataSource
  jpa:
    database: mysql
    show-sql: true
    hibernate:
      ddl-auto: update
      naming:
        physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
    database-platform: org.hibernate.dialect.MySQL5Dialect

4. 创建数据库配置类

第一个数据库配置类

package com.yyg.boot.config.properties;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description db1数据源配置类
 */
@ConfigurationProperties(prefix = "spring.datasource.ds1")
@Component("ds1Properties")
@Data
public class Ds1Properties {

    private String url;

    private String username;

    private String password;

    private String driverClassName;

}

第2个数据库配置类

package com.yyg.boot.config.properties;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description db4数据源配置类
 */
@ConfigurationProperties(prefix = "spring.datasource.ds2")
@Component("ds2Properties")
@Data
public class Ds2Properties {

    private String url;

    private String username;

    private String password;

    private String driverClassName;

}

5. 注册数据源

我们在一个类中注册两个数据源就可以了。

package com.yyg.boot.config;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceProperties;
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 javax.sql.DataSource;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description 数据源的配置类
 */
@Configuration
public class DataSourceRegisterConfig {

    /**
     * 主数据源配置 ds1数据源
     */
    @Primary
    @Bean(name = "ds1Properties")
    @ConfigurationProperties(prefix = "spring.datasource.ds1")
    public DataSourceProperties ds1DataSourceProperties() {
        return new DataSourceProperties();
    }

    /**
     * 主数据源 ds1数据源
     */
    @Primary
    @Bean(name = "ds1DataSource")
    public DataSource ds1DataSource(@Qualifier("ds1Properties") DataSourceProperties dataSourceProperties) {
        //HikariDataSource","org.apache.tomcat.jdbc.pool.DataSource", "org.apache.commons.dbcp2.BasicDataSource
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

    /**
     * 第二个ds2数据源配置
     */
    @Bean(name = "ds2Properties")
    @ConfigurationProperties(prefix = "spring.datasource.ds2")
    public DataSourceProperties ds2DataSourceProperties() {
        return new DataSourceProperties();
    }

    /**
     * 第二个ds2数据源
     */
    @Bean("ds2DataSource")
    public DataSource ds2DataSource(@Qualifier("ds2Properties") DataSourceProperties dataSourceProperties) {
        return dataSourceProperties.initializeDataSourceBuilder().build();
    }

}

6. 配置数据源、连接工厂、事务管理器、扫描dao目录

注意合理的使用@Primary注解！

配置第一个数据源管理器

package com.yyg.boot.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description 配置数据源、连接工厂、事务管理器、dao目录
 */
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "managerFactory1", // 配置连接工厂
        transactionManagerRef = "transactionManager1", // 配置事物管理器
        basePackages = {"com.yyg.boot.dao.db01"} // 设置dao所在位置

)
public class ManagerFactory01Config {

    /**
     * 配置数据源,连接第1个数据源
     */
    @Autowired
    @Qualifier("ds1DataSource")
    private DataSource ds1DataSource;

    @Primary
    @Bean(name = "managerFactory1")
    public LocalContainerEntityManagerFactoryBean buildEntityManagerFactory1(EntityManagerFactoryBuilder builder) {
        return builder
                // 设置数据源
                .dataSource(ds1DataSource)
                //设置实体类所在位置.扫描所有带有 @Entity 注解的类
                .packages("com.yyg.boot.entity")
                // Spring会将EntityManagerFactory注入到Repository之中.有了 EntityManagerFactory之后,
                // Repository就能用它来创建 EntityManager 了,然后 EntityManager 就可以针对数据库执行操作
                .persistenceUnit("ds1PersistenceUnit")
                .build();

    }

    /**
     * 配置事务管理器
     */
    @Bean(name = "transactionManager1")
    public PlatformTransactionManager transactionManagerDatabase1(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(buildEntityManagerFactory1(builder).getObject());
    }

}

配置第2个数据源管理器

package com.yyg.boot.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description 配置数据源、连接工厂、事务管理器、dao目录
 */
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "managerFactory2", // 配置连接工厂
        transactionManagerRef = "transactionManager2", // 配置事物管理器
        basePackages = {"com.yyg.boot.dao.db02"} // 设置dao所在位置

)
public class ManagerFactory02Config {

    /**
     * 配置数据源,连接第2个数据源
     */
    @Autowired
    @Qualifier("ds2DataSource")
    private DataSource ds2DataSource;

    @Bean(name = "managerFactory2")
    public LocalContainerEntityManagerFactoryBean buildEntityManagerFactory2(EntityManagerFactoryBuilder builder) {
        return builder
                // 设置数据源
                .dataSource(ds2DataSource)
                //设置实体类所在位置.扫描所有带有 @Entity 注解的类
                .packages("com.yyg.boot.entity")
                // Spring会将EntityManagerFactory注入到Repository之中.有了 EntityManagerFactory之后,
                // Repository就能用它来创建 EntityManager 了,然后 EntityManager 就可以针对数据库执行操作
                .persistenceUnit("ds2PersistenceUnit")
                .build();

    }

    /**
     * 配置事务管理器
     */
    @Bean(name = "transactionManager2")
    public PlatformTransactionManager transactionManagerDatabase1(EntityManagerFactoryBuilder builder) {
        return new JpaTransactionManager(buildEntityManagerFactory2(builder).getObject());
    }

}

7. 创建数据源类型

利用ThreadLocal确保线程安全性，每个线程之间不会相互影响。

package com.yyg.boot.datasource;

import lombok.extern.slf4j.Slf4j;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description 数据源类型
 */
@Slf4j
public class DataSourceType {

    public enum SourceType {
        /**
         * 用户数据源
         */
        DS_USER,
        /**
         * 商品数据源
         */
        DS_SHOP
    }

    /**
     * 使用ThreadLocal保证线程安全
     */
    private static final ThreadLocal<SourceType> TYPES = new ThreadLocal<>();

    /**
     * 往当前线程里设置数据源类型
     */
    public static void setDataSourceType(SourceType dataSourceType) {
        if (dataSourceType == null) {
            throw new NullPointerException();
        }
        log.warn("[设置当前数据源为]：" + dataSourceType);
        TYPES.set(dataSourceType);
    }

    /**
     * 获取数据源类型
     */
    public static SourceType getDataSourceType() {
        SourceType dataSourceType = TYPES.get() == null ? SourceType.DS_USER : TYPES.get();
        log.warn("[当前数据源的类型为]：" + dataSourceType);
        return dataSourceType;
    }

    /**
     * 清空数据类型
     */
    public static void removeDataSourceType() {
        TYPES.remove();
    }

}

8. 定义动态数据源

定义一个动态数据源,继承AbstractRoutingDataSource 抽象类，并重写determineCurrentLookupKey（）方法。

AbstractRoutingDataSource这个类是实现多数据源的关键，作用是动态切换数据源。
在该类中有一个targetDataSources集合，该集合是AbstractRoutingDataSource的一个map类型的属性，其中key表示每个数据源的名字，value为每个数据源。
然后根据determineCurrentLookupKey()这个方法获取当前数据源在map中的key值，然后determineTargetDataSource（）方法中动态获取当前数据源，如果当前数据源不存且默认数据源也不存在时就会抛出异常。

package com.yyg.boot.datasource;

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

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description 动态切换数据源
 */
public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceType.getDataSourceType();
    }

}

9. 配置多个数据源

package com.yyg.boot.datasource;

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

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description 多数据源配置
 */
@Configuration
public class DynamicDataSourceConfig {

    @Bean(name = "dynamicDataSource")
    public DynamicDataSource dynamicDataSource(@Qualifier("ds1DataSource") DataSource ds1DataSource,
                                        @Qualifier("ds2DataSource") DataSource ds2DataSource) {
        Map<Object, Object> targetDataSource = new HashMap<>();
        targetDataSource.put(DataSourceType.SourceType.DS_SHOP, ds1DataSource);
        targetDataSource.put(DataSourceType.SourceType.DS_USER, ds2DataSource);
        DynamicDataSource dataSource = new DynamicDataSource();
        dataSource.setTargetDataSources(targetDataSource);
        dataSource.setDefaultTargetDataSource(ds2DataSource);
        return dataSource;
    }

}

10. 定义AOP切面

package com.yyg.boot.datasource;

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

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description Description
 */
@Aspect
@Component
@Slf4j
public class DataSourceAop {

    @Before("execution(* com.yyg.boot.service.impl.GoodsServiceImpl.*(..))")
    public void setDataSource01() {
        log.warn("db01商品数据源");
        DataSourceType.setDataSourceType(DataSourceType.SourceType.DS_SHOP);
    }

    @Before("execution(* com.yyg.boot.service.impl.UserServiceImpl.*(..))")
    public void setDataSource02() {
        log.warn("db02用户数据源");
        DataSourceType.setDataSourceType(DataSourceType.SourceType.DS_USER);
    }

}

11. 创建Entity实体类

Goods商品类

package com.yyg.boot.entity;

import lombok.Data;

import javax.persistence.*;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description db1中的商品表
 */
@Entity
@Table(name = "goods")
@Data
public class Goods {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    private String name;

}

User用户类

package com.yyg.boot.entity;

import lombok.Data;

import javax.persistence.*;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description db4中的用户表
 */
@Entity
@Table(name = "user")
@Data
public class User {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    private String username;

    private String birthday;

    private String sex;

    private String address;

}

12. 创建Dao层代码

GoodsRepository类

package com.yyg.boot.dao.db01;

import com.yyg.boot.entity.Goods;
import com.yyg.boot.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.stereotype.Repository;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description Description
 */
@Repository
public interface GoodsRepository extends JpaRepository<Goods, Long>,JpaSpecificationExecutor<User> {
}

UserRepository类

package com.yyg.boot.dao.db02;

import com.yyg.boot.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.stereotype.Repository;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description Description
 */
@Repository
public interface UserRepository extends JpaRepository<User, Long>,JpaSpecificationExecutor<User> {
}

13. 创建Service代码

UserServiceImpl实现类

package com.yyg.boot.service.impl;

import com.yyg.boot.dao.db02.UserRepository;
import com.yyg.boot.entity.User;
import com.yyg.boot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description Description
 */
@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public List<User> findAll() {
        return userRepository.findAll();
    }

}

GoodsServiceImpl实现类

package com.yyg.boot.service.impl;

import com.yyg.boot.dao.db01.GoodsRepository;
import com.yyg.boot.dao.db02.UserRepository;
import com.yyg.boot.entity.Goods;
import com.yyg.boot.entity.User;
import com.yyg.boot.service.GoodsService;
import com.yyg.boot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/7
 * @Description Description
 */
@Service
public class GoodsServiceImpl implements GoodsService {

    @Autowired
    private GoodsRepository goodsRepository;

    @Override
    public List<Goods> findAll() {
        return goodsRepository.findAll();
    }

}

14. 创建Controller接口

package com.yyg.boot.web;

import com.yyg.boot.entity.Goods;
import com.yyg.boot.entity.User;
import com.yyg.boot.service.GoodsService;
import com.yyg.boot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description Description
 */
@RestController
public class GoodsController {

    @Autowired
    private UserService userService;

    @Autowired
    private GoodsService goodsService;

    @GetMapping(value = "/users")
    public List<User> users() {
        return userService.findAll();
    }

    @GetMapping(value = "/goods")
    public List<Goods> goods() {
        return goodsService.findAll();
    }

}

15. 创建入口类

package com.yyg.boot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/3
 * @Description Description
 */
@SpringBootApplication
public class DataSourceApplication {

    public static void main(String[] args){
        SpringApplication.run(DataSourceApplication.class,args);
    }

}