讲解下SpringBoot中MySql和MongoDB的配合使用

在Spring Boot中，MySQL和MongoDB可以配合使用，以充分发挥关系型数据库和非关系型数据库的优势。MySQL适合处理结构化数据，而MongoDB适合处理非结构化或半结构化数据。以下是如何在Spring Boot中同时使用MySQL和MongoDB的详细讲解。

1. 添加依赖

首先，在pom.xml中添加MySQL和MongoDB的依赖：

<dependencies><!-- Spring Boot Starter Data JPA for MySQL --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><!-- Spring Boot Starter Data MongoDB --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-mongodb</artifactId></dependency><!-- Other dependencies --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
</dependencies>

2. 配置数据源

在application.properties或application.yml中配置MySQL和MongoDB的连接信息。

`application.properties` 示例：

# MySQL 配置
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update# MongoDB 配置
spring.data.mongodb.uri=mongodb://localhost:27017/mydb

`application.yml` 示例：

spring:datasource:url: jdbc:mysql://localhost:3306/mydbusername: rootpassword: passworddriver-class-name: com.mysql.cj.jdbc.Driverjpa:hibernate:ddl-auto: updatedata:mongodb:uri: mongodb://localhost:27017/mydb

3. 创建实体类和Repository

MySQL 实体类和Repository

创建一个MySQL实体类并使用JPA注解进行映射：

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;@Entity
public class User {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String name;private String email;// Getters and Setters
}

创建对应的JPA Repository：

import org.springframework.data.jpa.repository.JpaRepository;public interface UserRepository extends JpaRepository<User, Long> {
}

MongoDB 实体类和Repository

创建一个MongoDB实体类并使用MongoDB注解进行映射：

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;@Document
public class Product {@Idprivate String id;private String name;private double price;// Getters and Setters
}

创建对应的MongoDB Repository：

import org.springframework.data.mongodb.repository.MongoRepository;public interface ProductRepository extends MongoRepository<Product, String> {
}

4. 使用不同的Repository进行操作

在Service或Controller中，你可以分别使用UserRepository和ProductRepository来操作MySQL和MongoDB。

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class MyService {@Autowiredprivate UserRepository userRepository;@Autowiredprivate ProductRepository productRepository;public void addUser(User user) {userRepository.save(user);}public void addProduct(Product product) {productRepository.save(product);}public User getUserById(Long id) {return userRepository.findById(id).orElse(null);}public Product getProductById(String id) {return productRepository.findById(id).orElse(null);}
}