SpringBoot+MyBatisPlus+AOP实现多数据源切换

1、背景

在实际开发过程中，我们可能会出现需要用到多数据源的情况，就是应用中可能需要根据场景的不同，对不同的数据库进行操作，此时需要进行多数据源的配置和开发了，在网上看到了很多案例，实现方式各不一样，我这里给大家梳理出来的实现方案是基于AOP+自定义注解实现的，为什么这里介绍这种方案呢？因为这种方案使用起来非常方便快捷，可扩展性和可维护性高

2、环境准备

https://gitee.com/colinWu_java/spring-boot-base.git

大家可以先把上面这个这个项目拉下来，我会基于这个主干项目之上进行开发

3、编码实战

3.1、建库脚本

我们现在做多数据源的测试，所以我在本地新建了两个数据库，分别取名叫做test1和test2，两个库新建同一张表，叫做t_user，建表语句如下：

DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
  `name` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '姓名',
  `age` int(11) NULL DEFAULT NULL COMMENT '年龄',
  `phone` varchar(11) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '手机号',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 13 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '用户表' ROW_FORMAT = Dynamic;

3.2、pom依赖

主要是需要导入aop的依赖

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>

    <groupId>org.examplegroupId>
    <artifactId>SpringBootBaseartifactId>
    <version>1.0-SNAPSHOTversion>

    <properties>
        <maven.compiler.source>8maven.compiler.source>
        <maven.compiler.target>8maven.compiler.target>
    properties>

    
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>2.0.5.RELEASEversion>
    parent>

    <dependencies>
        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <scope>testscope>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>

        
        <dependency>
            <groupId>com.baomidougroupId>
            <artifactId>mybatis-plus-boot-starterartifactId>
            <version>3.0.5version>
        dependency>

        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
        dependency>

        
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>druid-spring-boot-starterartifactId>
            <version>1.1.18version>
        dependency>

        
        <dependency>
            <groupId>org.apache.velocitygroupId>
            <artifactId>velocity-engine-coreartifactId>
            <version>2.0version>
        dependency>

        
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
        dependency>

        
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>fastjsonartifactId>
            <version>1.2.50version>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-aopartifactId>
        dependency>

    dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
                <version>2.3.5.RELEASEversion>
            plugin>
        plugins>
        <finalName>SpringBootBasefinalName>
    build>

project>

3.3、yml配置

server:
  port: 8001
spring:
  #配置数据库信息
  datasource:
    druid: # 全局druid参数
      # 连接池的配置信息
      db1:
        url: jdbc:mysql://127.0.0.1:3306/test1?characterEncoding=UTF-8&useUnicode=true&serverTimezone=UTC&useSSL=false
        username: root
        password: 123456
      db2:
        url: jdbc:mysql://127.0.0.1:3306/test2?characterEncoding=UTF-8&useUnicode=true&serverTimezone=UTC&useSSL=false
        username: root
        password: 123456
      driver-class-name: com.mysql.jdbc.Driver
      # 初始化大小，最小，最大
      initial-size: 5
      min-idle: 5
      maxActive: 20
      # 配置获取连接等待超时的时间
      maxWait: 60000
      # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
      timeBetweenEvictionRunsMillis: 60000
      # 配置一个连接在池中最小生存的时间，单位是毫秒
      minEvictableIdleTimeMillis: 300000
      validationQuery: SELECT 1 FROM DUAL
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      # 打开PSCache，并且指定每个连接上PSCache的大小
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      stat-view-servlet:
        enabled: true
        #网页访问地址：http://localhost:8001/druid/login.html
        url-pattern: /druid/*
        login-username: admin
        login-password: 123456
  application:
    name: SpringBootBase #服务名

#MyBatis-Plus相关配置
mybatis-plus:
  #指定Mapper.xml路径，如果与Mapper路径相同的话，可省略
  mapper-locations: classpath:org/wujiangbo/mapper/*Mapper.xml
  configuration:
    map-underscore-to-camel-case: true #开启驼峰大小写自动转换
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #开启控制台sql输出

3.4、实体类

package org.wujiangbo.domain;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.baomidou.mybatisplus.extension.activerecord.Model;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import java.io.Serializable;

/**
 * 

 * 用户表
 * 
 *
 * @author 波波老师(weixin：javabobo0513)
 */
@TableName("t_user")
@ToString
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User extends Model<User> {

    private static final long serialVersionUID = 1L;

    /**
     * 主键ID
     */
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;
    /**
     * 姓名
     */
    private String name;
    /**
     * 年龄
     */
    private Integer age;
    /**
     * 手机号
     */
    private String phone;

    @Override
    protected Serializable pkVal() {
        return this.id;
    }
}

3.5、controller层

package org.wujiangbo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.wujiangbo.annotation.DataSource;
import org.wujiangbo.domain.User;
import org.wujiangbo.result.JSONResult;
import org.wujiangbo.service.IUserService;

/**
 * @desc UserController
 * @author 波波老师(weixin：javabobo0513)
 */
@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    public IUserService userService;

    /**
     * 保存数据到ds1数据源中，可以不写，那就是默认选择数据源1
     */
    @PostMapping(value="/saveDb1")
    @DataSource(name = "db1")
    public JSONResult saveDb1(@RequestBody User user){
        userService.saveUser1(user);
        return JSONResult.success();
    }

    /**
     * 保存数据到ds2数据源中
     */
    @PostMapping(value="/saveDb2")
    @DataSource(name = "db2")
    public JSONResult saveDb2(@RequestBody User user){
        userService.saveUser2(user);
        return JSONResult.success();
    }

    /**
     * 从ds1数据源中查询数据
     */
    @PostMapping(value="/queryDb1")
    @DataSource(name = "db1")
    public JSONResult queryDb1(){
        return JSONResult.success(userService.list(null));
    }
}

3.6、service层

接口：

package org.wujiangbo.service;

import com.baomidou.mybatisplus.extension.service.IService;
import org.wujiangbo.domain.User;

/**
 * 

 * 用户表 服务类
 * 
 *
 * @author 波波老师(weixin：javabobo0513)
 */
public interface IUserService extends IService<User> {
    void saveUser1(User user);

    void saveUser2(User user);
}

实现类：

package org.wujiangbo.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;
import org.wujiangbo.domain.User;
import org.wujiangbo.mapper.UserMapper;
import org.wujiangbo.service.IUserService;

/**
 * 

 * 用户表 服务实现类
 * 
 *
 * @author 波波老师(weixin：javabobo0513)
 * @since 2022-11-01
 */
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {

    @Override
    public void saveUser1(User user) {
        super.save(user);
    }

    @Override
    public void saveUser2(User user) {
        super.save(user);
    }
}

3.7、mapper层

package org.wujiangbo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.wujiangbo.domain.User;

/**
 * 

 * 用户表 Mapper 接口
 * 
 *
 * @author 波波老师(weixin：javabobo0513)
 */
public interface UserMapper extends BaseMapper<User> {
}

3.8、自定义注解

package org.wujiangbo.annotation;

import java.lang.annotation.*;

/**
 * @desc 自定义注解：实现多数据源
 * @author 波波老师(weixin：javabobo0513)
 */
@Target({ElementType.TYPE,ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataSource {
     String name() default "";
}

3.9、切面类

package org.wujiangbo.aspect;

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.wujiangbo.annotation.DataSource;
import org.wujiangbo.config.datasource.DynamicDataSource;
import java.lang.reflect.Method;

/**
 * 切面处理类，处理多数据源相关功能
 * @author 波波老师(weixin：javabobo0513)
 */
@Slf4j
@Aspect
@Component
public class DataSourceAspect implements Ordered {

   //定义切入点
   @Pointcut("@annotation(org.wujiangbo.annotation.DataSource)")
   public void pointCut() {
   }

   //环绕通知
   @Around("pointCut()")
   public Object around(ProceedingJoinPoint point) throws Throwable {
      MethodSignature signature = (MethodSignature) point.getSignature();
      Method method = signature.getMethod();
      DataSource ds = method.getAnnotation(DataSource.class);
      //开始设置数据源
      if (ds == null) {
         //设置默认数据源
         DynamicDataSource.setDataSource("db1");
         log.info("set datasource is " + ds.name());
      } else {
         DynamicDataSource.setDataSource(ds.name());
         log.info("set datasource is " + ds.name());
      }
      try {
         return point.proceed();
      } finally {
         DynamicDataSource.clearDataSource();
         log.info("clean datasource");
      }
   }

   @Override
   public int getOrder() {
      return 1;
   }
}

3.10、多数据源配置类

package org.wujiangbo.config.datasource;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import javax.sql.DataSource;
import java.util.Map;

/**
 * @desc 动态数据源
 * @author 波波老师(weixin：javabobo0513)
 */
public class DynamicDataSource extends AbstractRoutingDataSource {
   private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

   public DynamicDataSource(DataSource defaultTargetDataSource, Map<Object, Object> targetDataSources) {
      super.setDefaultTargetDataSource(defaultTargetDataSource);
      super.setTargetDataSources(targetDataSources);
      super.afterPropertiesSet();
   }

   @Override
   protected Object determineCurrentLookupKey() {
      return getDataSource();
   }

   public static void setDataSource(String dataSource) {
      contextHolder.set(dataSource);
   }

   public static String getDataSource() {
      return contextHolder.get();
   }

   public static void clearDataSource() {
      contextHolder.remove();
   }

}

配置类：

package org.wujiangbo.config.datasource;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
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;
import java.util.HashMap;
import java.util.Map;

/**
 * @desc 动态数据源配置类
 * @author 波波老师(weixin：javabobo0513)
 */
@Configuration
public class DynamicDataSourceConfig {

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

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

   @Bean
   @Primary
   public DynamicDataSource dataSource(DataSource firstDataSource, DataSource secondDataSource) {
      Map<Object, Object> targetDataSources = new HashMap<>();
      targetDataSources.put("db1", firstDataSource);
      targetDataSources.put("db2", secondDataSource);
      return new DynamicDataSource(firstDataSource, targetDataSources);
   }
}

4、测试

用postman工具分别访问接口：

• http://localhost:8001/user/saveDb1
• http://localhost:8001/user/saveDb2

调用两次后，再去看数据库，就会发现test1和test2数据库就有数据了，测试成功

以上代码都已经提交到git中的【MultiDataSource1】分支中了

5、总结

1. 自定义注解+AOP这种方式实现多数据源的切换，体验起来非常丝滑，很方便
2. 希望对大家有点帮助，赶紧动手测试一下吧