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介紹
JPA(Java Persistence API)Java 持久化 API,是 Java 持久化的標準規范,Hibernate 是持久化規范的技術實現,而 Spring Data JPA 是在 Hibernate 基礎上封裝的一款框架。
第一次使用 Spring JPA 的時候,感覺這東西簡直就是神器,幾乎不需要寫什么關于數據庫訪問的代碼一個基本的 CURD 的功能就出來了。在這篇文章中,我們將介紹 Spring Boot 整合 JPA 使用多個數據源的方法。
開發環境:
引入依賴
首先我們要 Spring Boot 引入 spring-boot-starter-data-jpa 依賴。
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'
配置數據源
Spring Boot 提供了使用 application.properties 或 application.yml 文件配置項目屬性的方法。我比較習慣使用 application.yml 文件,所以這里我只列出 application.yml 文件的寫法。
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 文件后分別在數據庫創建 customer 和 product 數據庫。
添加實體(Entity)類
客戶實體:
package com.springboot.jpa.customer.models; import javax.persistence.*; @Entity public 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; } }
產品實體:
package com.springboot.jpa.product.models; import javax.persistence.*; @Entity public 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; } }
添加數據倉庫(Repository)類
客戶 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; @Repository public interface CustomerRepository extends JpaRepository<Customer, Integer> { }
產品 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; @Repository public interface ProductRepository extends JpaRepository<Product, Integer> { }
添加配置(Config)類
客戶配置:
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); } }
產品配置:
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); } }
項目結構:
src/main/java
- com.springboot.jpa
- product
- config
- models
- repository
- customer
- config
- models
- repository
添加測試類
客戶測試類 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) @SpringBootTest public 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"); } }
產品測試類 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) @SpringBootTest public 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())); } }
測試
分別運行兩個測試類通過后,查詢數據庫。
客戶表:
mysql> SELECT * FROM customer; +----+-------------------+-----------+----------+ | id | email | firstName | lastName | +----+-------------------+-----------+----------+ | 1 | master@weilog.net | Charles | Zhang | +----+-------------------+-----------+----------+ 1 row in set
產品表:
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 使用多個數據源
項目地址:spring-boot-jpa
總結
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