Spring Data JPA是Spring基于Hibernate开发的一个JPA框架。如果用过Hibernate或者MyBatis的话,就会知道对象关系映射(ORM)框架有多么方便。
但是Spring Data JPA框架功能更进一步,为我们做了 一个数据持久层框架几乎能做的任何事情。下面来逐步介绍它的强大功能。
直接上代码:
pom.xml
<!-- hibernate start --> <!-- spring data jpa --> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-jpa</artifactId> <version>2.1.3.RELEASE</version> </dependency> <!-- hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>5.4.0.Final</version> </dependency> <!-- hibernate end -->
项目结构:
the_data_jpa 包 里面的 各类 代码
User
package com.oukele.the_data_jpa.entity; import org.springframework.stereotype.Component; import javax.persistence.*; @Entity @Table(name = "user") public class User { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "Id") private int id; @Column(name = "userName") private String name; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
UserDao
package com.oukele.the_data_jpa.dao; import com.oukele.the_data_jpa.entity.User; import org.springframework.data.jpa.repository.JpaRepository; import java.util.List; public interface UserDao extends JpaRepository<User, Integer> { User findByNameAndPassword(String name,String password); }
UserService
package com.oukele.the_data_jpa.service; import com.oukele.the_data_jpa.dao.UserDao; import com.oukele.the_data_jpa.entity.User; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.data.jpa.repository.Query; import org.springframework.stereotype.Service; import java.util.List; @Service public class UserService { @Autowired private UserDao userDao; public User findNameAndPassword(String name,String password){ return userDao.findByNameAndPassword(name, password); } public List<User> list(){ List<User> list = userDao.findAll(); return list; } }
SpringConfig
package com.oukele.the_data_jpa; import com.mchange.v2.c3p0.ComboPooledDataSource; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.PropertySource; import org.springframework.core.env.Environment; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; import org.springframework.jdbc.datasource.DataSourceTransactionManager; import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean; import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter; import org.springframework.transaction.PlatformTransactionManager; import javax.sql.DataSource; import java.beans.PropertyVetoException; import java.util.Properties; @Configuration//声明当前配置类 @ComponentScan(basePackages = "com.oukele.the_data_jpa")// 扫描当前包 使用 spring 注解 @PropertySource("classpath:jdbc.properties")//加载 资源文件 @EnableJpaRepositories(basePackages = "com.oukele.the_data_jpa.dao")//扫描 使用 jpa 注解的接口 public class SpringConfig { //配置数据源 @Bean DataSource dataSource(Environment env) throws PropertyVetoException { ComboPooledDataSource dataSource = new ComboPooledDataSource(); dataSource.setDriverClass(env.getProperty("jdbc.driver")); dataSource.setJdbcUrl(env.getProperty("jdbc.url")); dataSource.setUser(env.getProperty("jdbc.user")); dataSource.setPassword(env.getProperty("jdbc.password")); return dataSource; } // @Bean // public JdbcTemplate jdbcTemplate() { // JdbcTemplate jdbcTemplate = new JdbcTemplate(); // jdbcTemplate.setDataSource(dataSource1); // return jdbcTemplate; // } @Bean public PlatformTransactionManager transactionManager(DataSource dataSource) { return new DataSourceTransactionManager(dataSource); } //SqlSessionFactory @Bean LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource){ LocalContainerEntityManagerFactoryBean bean = new LocalContainerEntityManagerFactoryBean(); bean.setDataSource(dataSource); //加载 实体类 bean.setPackagesToScan("com.oukele.the_data_jpa.entity"); //设置 适配器 bean.setJpaVendorAdapter(new HibernateJpaVendorAdapter()); Properties properties = new Properties(); //更新表结构 properties.setProperty("hibernate.hbm2ddl.auto", "update"); //设置方言 properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect"); bean.setJpaProperties(properties); return bean; } }
Main ( 测试 类)
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package com.oukele.the_data_jpa; import com.oukele.the_data_jpa.entity.User; import com.oukele.the_data_jpa.service.UserService; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import java.util.List; public class Main { public static void main(String[] args) { AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class); UserService service = context.getBean(UserService.class); User user = service.findNameAndPassword("oukele","oukele"); System.out.println(user.getName()); List< User > list = service.list(); for (User user1 : list) { System.out.println(user1.getName()+" - "+user1.getPassword()); } } } |
测试结果:
1 oukele 2 oukele - oukele
jdbc.properties文件:
jdbc.driver=org.mariadb.jdbc.Driver jdbc.url=jdbc:mariadb://localhost:3306/test jdbc.user=oukele jdbc.password=oukele