介绍

JPA（Java Persistence API）Java 持久化 API，是 Java 持久化的标准规范，Hibernate 是持久化规范的技术实现，而 Spring Data JPA 是在 Hibernate 基础上封装的一款框架。

第一次使用 Spring JPA 的时候，感觉这东西简直就是神器，几乎不需要写什么关于数据库访问的代码一个基本的 CURD 的功能就出来了。在这篇文章中，我们将介绍 Spring Boot 整合 JPA 使用多个数据源的方法。

开发环境：

• Spring Boot 2.0.5
• Spring Data JPA 2.0.5
• MySQL 5.6
• JDK 8
• IDEA 2018.3
• Windows 10

引入依赖

首先我们要 Spring Boot 引入 spring-boot-starter-data-jpa 依赖。

Maven 配置：

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency>

Gradle 配置：

compile group: 'org.springframework.boot', name: 'spring-boot-starter-data-jpa', version: '2.0.5.RELEASE'compile group: 'org.springframework.boot', name: 'spring-boot-starter-web', version: '2.0.5.RELEASE'compile group: 'org.springframework.boot', name: 'spring-boot-devtools', version: '2.0.5.RELEASE'compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.6'

配置数据源

Spring Boot 提供了使用 application.properties 或 application.yml 文件配置项目属性的方法。我比较习惯使用 application.yml 文件，所以这里我只列出 application.yml 文件的写法。

spring: datasource: product: driver-class-name: com.mysql.jdbc.Driver jdbc-url: jdbc:mysql://127.0.0.1:3306/product?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&autoReconnect=true&useSSL=false&zeroDateTimeBehavior=convertToNull username: root password: test123$ customer: driver-class-name: com.mysql.jdbc.Driver jdbc-url: jdbc:mysql://127.0.0.1:3306/customer?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&autoReconnect=true&useSSL=false&zeroDateTimeBehavior=convertToNull username: root password: test123$ jpa: generate-ddl: true

配置好 application.yml 文件后分别在数据库创建 customer 和 product 数据库。

添加实体（Entity）类

客户实体：

package com.springboot.jpa.customer.models;import javax.persistence.*;@Entitypublic class Customer { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; @Column(unique = true, nullable = false) private String email; private String firstName; private String lastName; protected Customer() { } public Customer(String email, String firstName, String lastName) { this.email = email; this.firstName = firstName; this.lastName = lastName; } @Override public String toString() { return String.format("Customer[id=%d, firstName='%s', lastName='%s',email='%s']", id, firstName, lastName, email); } public Integer getId() { return id; } public String getEmail() { return email; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; }}

产品实体：

package com.springboot.jpa.product.models;import javax.persistence.*;@Entitypublic class Product { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private int id; @Column(nullable = false) private String code; private String name; private double price; protected Product() { } public Product(String code, String name, double price) { this.code = code; this.name = name; this.price = price; } @Override public String toString() { return String.format("Product[id=%d, code='%s', name='%s', price='%s']", id, code, name, price); } public int getId() { return id; } public String getCode() { return code; } public String getName() { return name; } public double getPrice() { return price; }}

添加数据仓库（Repository）类

客户 Repository：

package com.springboot.jpa.customer.repository;import com.springboot.jpa.customer.models.Customer;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.stereotype.Repository;@Repositorypublic interface CustomerRepository extends JpaRepository<Customer, Integer> {}

产品 Repository：

package com.springboot.jpa.product.repository;import com.springboot.jpa.product.models.Product;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.stereotype.Repository;@Repositorypublic interface ProductRepository extends JpaRepository<Product, Integer> {}

添加配置（Config）类

客户配置：

package com.springboot.jpa.customer.config;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.boot.jdbc.DataSourceBuilder;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.persistence.EntityManagerFactory;import javax.sql.DataSource;@Configuration@EnableTransactionManagement@EnableJpaRepositories(entityManagerFactoryRef = "customerEntityManagerFactory", transactionManagerRef = "customerTransactionManager", basePackages = {"com.springboot.jpa.customer.repository"})public class CustomerConfig { @Primary @Bean(name = "customerDataSource") @ConfigurationProperties(prefix = "spring.datasource.customer") public DataSource customerDataSource() { return DataSourceBuilder.create().build(); } @Primary @Bean(name = "customerEntityManagerFactory") public LocalContainerEntityManagerFactoryBean entityManagerFactory(EntityManagerFactoryBuilder builder, @Qualifier("customerDataSource") DataSource dataSource) { return builder.dataSource(dataSource).packages("com.springboot.jpa.customer.models").persistenceUnit("customer").build(); } @Primary @Bean(name = "customerTransactionManager") public PlatformTransactionManager customerTransactionManager(@Qualifier("customerEntityManagerFactory") EntityManagerFactory customerEntityManagerFactory) { return new JpaTransactionManager(customerEntityManagerFactory); }}

产品配置：

package com.springboot.jpa.product.config;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.boot.context.properties.ConfigurationProperties;import org.springframework.boot.jdbc.DataSourceBuilder;import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;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.persistence.EntityManagerFactory;import javax.sql.DataSource;@Configuration@EnableTransactionManagement@EnableJpaRepositories(entityManagerFactoryRef = "productEntityManagerFactory", transactionManagerRef = "productTransactionManager", basePackages = {"com.springboot.jpa.product.repository"})public class ProductConfig { @Bean(name = "productDataSource") @ConfigurationProperties(prefix = "spring.datasource.product") public DataSource dataSource() { return DataSourceBuilder.create().build(); } @Bean(name = "productEntityManagerFactory") public LocalContainerEntityManagerFactoryBean barEntityManagerFactory(EntityManagerFactoryBuilder builder, @Qualifier("productDataSource") DataSource dataSource) { return builder.dataSource(dataSource).packages("com.springboot.jpa.product.models").persistenceUnit("product").build(); } @Bean(name = "productTransactionManager") public PlatformTransactionManager productTransactionManager(@Qualifier("productEntityManagerFactory") EntityManagerFactory productEntityManagerFactory) { return new JpaTransactionManager(productEntityManagerFactory); }}

项目结构：

src/main/java
- com.springboot.jpa
- product
- config
- models
- repository
- customer
- config
- models
- repository

添加测试类

客户测试类 CustomerDataSourcesTests：

package com.springboot.jpa;import com.springboot.jpa.customer.repository.CustomerRepository;import com.springboot.jpa.customer.models.Customer;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.test.context.junit4.SpringRunner;import org.springframework.transaction.annotation.Transactional;import org.junit.Test;import static org.junit.Assert.assertEquals;import static org.junit.Assert.assertNotNull;@RunWith(SpringRunner.class)@SpringBootTestpublic class CustomerDataSourcesTests { @Autowired private CustomerRepository customerRepository; @Test @Transactional("customerTransactionManager") public void createCustomer() { Customer customer = new Customer("master@weilog.net", "Charles", "Zhang"); customer = customerRepository.save(customer); assertNotNull(customerRepository.findById(customer.getId())); assertEquals(customerRepository.findById(customer.getId()).get().getEmail(), "master@weilog.net"); }}

产品测试类 ProductDataSourcesTests：

package com.springboot.jpa;import com.springboot.jpa.product.models.Product;import com.springboot.jpa.product.repository.ProductRepository;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.test.context.junit4.SpringRunner;import org.springframework.transaction.annotation.Transactional;import org.junit.Test;import static org.junit.Assert.assertNotNull;@RunWith(SpringRunner.class)@SpringBootTestpublic class ProductDataSourcesTests { @Autowired private ProductRepository productRepository; @Test @Transactional("productTransactionManager") public void createProduct() { Product product = new Product("10000", "Book", 80.0); product = productRepository.save(product); assertNotNull(productRepository.findById(product.getId())); }}

测试

分别运行两个测试类通过后，查询数据库。

客户表：

mysql> SELECT * FROM customer;+----+-------------------+-----------+----------+| id | email | firstName | lastName |+----+-------------------+-----------+----------+| 1 | master@weilog.net | Charles | Zhang |+----+-------------------+-----------+----------+1 row in set

产品表：

mysql> SELECT * FROM product;+----+-------+------+-------+| id | code | name | price |+----+-------+------+-------+| 1 | 10000 | Book | 80 |+----+-------+------+-------+1 row in set

本文地址：Spring Boot 整合 JPA 使用多个数据源

项目地址：spring-boot-jpa

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，谢谢大家对的支持。