Hibernate、Jpa与Spring data Jpa三者关系与整合
目录
- 简介
- Hibernate基础
- hibernate查询的四种方式
- Hibernate+JPA
- Spring + Spring data jpa + hibernate
简介
Hibernate
Hibernate是一个开放源代码的对象关系映射框架，它对JDBC进行了非常轻量级的对象封装，它将POJO与数据库表建立映射关系，是一个全自动的orm框架，hibernate可以自动生成SQL语句，自动执行，使得Java程序员可以随心所欲的使用对象编程思维来操纵数据库。
JPA
JPA全称是Java Persistence API，即java持久化API，是sun公司推出的一套基于ORM的规范，内部由一系列的接口和抽象类构成。
JPA与Hibetnate的关系
JPA和Hibernate的关系就像JDBC和JDBC驱动的关系，JPA是规范，Hibernate除了作为ORM框架之外，它也是一种JPA实现。JPA怎么取代Hibernate呢？JDBC规范可以驱动底层数据库吗？答案是否定的，也就是说，如果使用JPA规范进行数据库操作，底层需要hibernate作为其实现类完成数据持久化工作。
Spring Data jpa
Spring Data JPA 让我们解脱了DAO层的操作，基本上所有CRUD都可以依赖于它来实现,在实际的工作工程中，推荐使用Spring Data JPA + ORM（如：hibernate）完成操作，这样在切换不同的ORM框架时提供了极大的方便，同时也使数据库层操作更加简单，方便解耦
Hibernate、JPA与Spring Data JPA之间的关系
JPA是一套规范，内部是有接口和抽象类组成的。hibernate是一套成熟的ORM框架，而且Hibernate实现了JPA规范，所以也可以称hibernate为JPA的一种实现方式，我们使用JPA的API编程，意味着站在更高的角度上看待问题（面向接口编程）Spring Data JPA是Spring提供的一套对JPA操作更加高级的封装，是在JPA规范下的专门用来进行数据持久化的解决方案。
以上就是对hibernate、JPA与Spring Data JPA三者之间的关系说明。
ORM 表示 Object-Relational Mapping (ORM)对象关系映射
Hibernate基础
maven依赖
<dependencies>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.11version>
dependency>
<dependency>
<groupId>org.hibernategroupId>
<artifactId>hibernate-coreartifactId>
<version>5.3.5.Finalversion>
dependency>
<dependency>
<groupId>org.hibernategroupId>
<artifactId>hibernate-c3p0artifactId>
<version>5.3.5.Finalversion>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.12version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.19version>
dependency>
<dependency>
<groupId>javax.xml.bindgroupId>
<artifactId>jaxb-apiartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>com.sun.xml.bindgroupId>
<artifactId>jaxb-implartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>com.sun.xml.bindgroupId>
<artifactId>jaxb-coreartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>javax.activationgroupId>
<artifactId>activationartifactId>
<version>1.1.1version>
dependency>
dependencies>
创建配置文件hibernate.cfg.xml放在resources中
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.MySQL8Dialectproperty>
<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driverproperty>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/ssm?useSSL=false&characterEncoding=UTF-8&serverTimezone=UTCproperty>
<property name="hibernate.connection.username">rootproperty>
<property name="hibernate.connection.password">passwordproperty>
<property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProviderproperty>
<property name="hibernate.show_sql">trueproperty>
<property name="hibernate.format_sql">trueproperty>
<property name="hibernate.hbm2ddl.auto">updateproperty>
<property name="hibernate.current_session_context_class">threadproperty>
<mapping resource="com/haoxuan/dao/User.hbm.xml" />
session-factory>
hibernate-configuration>
实体类User.java
package com.haoxuan.entity;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Integer id;
private String name;
private String password;
private String tel;
}
创建映射文件User.hbm.xml
<hibernate-mapping>
<class name="com.haoxuan.entity.User" table="user">
<id name="id" column="id">
<generator class="native">generator>
id>
<property name="name" column="username">property>
<property name="password" column="password">property>
<property name="tel" column="tel">property>
class>
hibernate-mapping>
创建工具类HibernateUtil.java
package com.haoxuan.util;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
static Configuration configuration = null;
static SessionFactory sessionFactory = null;
static {
configuration = new Configuration();
configuration.configure();
sessionFactory = configuration.buildSessionFactory();
}
public static Session openSession()
{
return sessionFactory.openSession();
}
public static Session getCurrentSession()
{
Session session = sessionFactory.getCurrentSession();
return session;
}
}
hibernate查询的四种方式
1、主键查询
2、HQL查询
3、Criteria查询
4、本地sql查询
测试
public class HibernateTest {
/*
主键查询get、load
区别：hibernate对于 load方法认为该数据在数据库中一定存在，可以放心的使用代理来延迟加载，
如果在使用过程中发现了问题，只能抛异常；而对于get方法，hibernate一定要获取到真实
的数据，否则返回null。
*/
@Test
public void hibernate1() {
Session session = HibernateUtil.openSession();
Transaction tx = session.beginTransaction();
//get(实体类,主键);
User user = session.get(User.class,1);
System.out.println(user);
tx.commit();
session.close();
}
/*
save()方法
出现java.sql.SQLException: Field 'id' doesn't have a default value报错
说明没有为主键设置自增
*/
@Test
public void hibernate2() {
Session session = HibernateUtil.openSession();
Transaction tx = session.beginTransaction();
User user = new User(2,"name","word","13174851256");
session.save(user);
tx.commit();
session.close();
}
/*
使用hql,操作的对象为实体类
1、查询全部字段，list封装的为对象的实体类
2、只查询一个字段，默认情况下，list封装的是Object对象
3、查询两个或两个以上字段，默认情况下，list封装的是Object[],长度与所查询的字段数一致。
*/
@Test
public void hibernate3() {
Session session = HibernateUtil.openSession();
Transaction tx = session.beginTransaction();
String hql = "select u.name,u.tel from User u where u.id=1";
Query query = session.createQuery(hql);
List<Object[]> result = query.list();
for (Object[] objs : result) {
System.out.println("name:"+objs[0]);
System.out.println("tel:"+objs[1]);
}
}
/*
使用原生sql
*/
@Test
public void hibernate4() {
Session session = HibernateUtil.openSession();
Transaction tx = session.beginTransaction();
String sql = "select username,tel from user where id=1";
Query query = session.createSQLQuery(sql);
List<Object[]> result = query.list();
for (Object[] objs : result) {
System.out.println("name:"+objs[0]);
System.out.println("tel:"+objs[1]);
}
}
/*
标准查询Criteria
*/
@Test
public void hibernate5() {
Session session = HibernateUtil.openSession();
Transaction tx = session.beginTransaction();
Criteria criteria = session.createCriteria(User.class);
criteria.add(Restrictions.eq("id",1));
List<User> result = criteria.list();
for (User user : result) {
System.out.println(user);
}
}
}
Hibernate+JPA
maven依赖
<dependencies>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.11version>
dependency>
<dependency>
<groupId>org.hibernategroupId>
<artifactId>hibernate-entitymanagerartifactId>
<version>5.3.5.Finalversion>
dependency>
<dependency>
<groupId>org.hibernategroupId>
<artifactId>hibernate-c3p0artifactId>
<version>5.3.5.Finalversion>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.12version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.19version>
dependency>
dependencies>
配置文件，放在resource文件夹中的META-INF中 persistent.xml
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="myJpa" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.jpa.HibernatePersistenceProviderprovider>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/ssm?characterEncoding=utf-8" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="password" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.format_sql" value="true" />
<property name="hibernate.hbm2ddl.auto" value="update" />
properties>
persistence-unit>
persistence>
工具类JpaUtil.java
package com.haoxuan.util;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
public class JpaUtil {
private static EntityManagerFactory entityManagerFactory;
static {
entityManagerFactory = Persistence.createEntityManagerFactory("myJpa");
}
public static EntityManager getEntityManager() {
return entityManagerFactory.createEntityManager();
}
}
测试类
package com.haoxuan.test;
import com.haoxuan.entity.User;
import com.haoxuan.util.JpaUtil;
import org.junit.Test;
import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
public class JpaTest {
/*
persist ： 保存操作
merge ： 更新操作
remove ： 删除操作
find（立即加载）/getReference（延迟加载） ： 根据id查询
*/
@Test
public void jpaTest1(){
EntityManager em = JpaUtil.getEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
User user = em.find(User.class,1);
System.out.println(user);
}
}
Spring + Spring data jpa + hibernate
maven依赖
<dependencies>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.12version>
dependency>
<dependency>
<groupId>org.springframework.datagroupId>
<artifactId>spring-data-jpaartifactId>
<version>2.3.0.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframework.datagroupId>
<artifactId>spring-data-commonsartifactId>
<version>2.3.0.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-coreartifactId>
<version>5.2.6.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-contextartifactId>
<version>5.2.6.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-beansartifactId>
<version>5.2.6.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>5.2.6.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-testartifactId>
<version>5.2.6.RELEASEversion>
dependency>
<dependency>
<groupId>org.hibernategroupId>
<artifactId>hibernate-coreartifactId>
<version>5.3.5.Finalversion>
dependency>
<dependency>
<groupId>javax.xml.bindgroupId>
<artifactId>jaxb-apiartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>com.sun.xml.bindgroupId>
<artifactId>jaxb-implartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>com.sun.xml.bindgroupId>
<artifactId>jaxb-coreartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>javax.activationgroupId>
<artifactId>activationartifactId>
<version>1.1.1version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.12version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druidartifactId>
<version>1.1.21version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>8.0.19version>
dependency>
<dependency>
<groupId>log4jgroupId>
<artifactId>log4jartifactId>
<version>1.2.17version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-apiartifactId>
<version>2.0.0-alpha1version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-log4j12artifactId>
<version>2.0.0-alpha1version>
dependency>
dependencies>
创建spring配置文件applicationContext.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/data/jpa
http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver" />
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/jpa?characterEncoding=utf-8" />
<property name="user" value="root" />
<property name="password" value="password" />
bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.ithubei.entity" />
<property name="persistenceProvider">
<bean class="org.hibernate.jpa.HibernatePersistenceProvider" />
property>
<property name="jpaProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialectprop>
<prop key="hibernate.show_sql">trueprop>
<prop key="hibernate.format_sql">trueprop>
<prop key="hibernate.hbm2ddl.auto">updateprop>
props>
property>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="generateDdl" value="false" />
<property name="database" value="MYSQL" />
<property name="databasePlatform" value="org.hibernate.dialect.MySQL8Dialect" />
bean>
property>
<property name="jpaDialect">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" />
property>
bean>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
bean>
<jpa:repositories base-package="com.ithubei.dao"
transaction-manager-ref="transactionManager"
entity-manager-factory-ref="entityManagerFactory">jpa:repositories>
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="save*" propagation="REQUIRED"/>
<tx:method name="insert*" propagation="REQUIRED"/>
<tx:method name="update*" propagation="REQUIRED"/>
<tx:method name="delete*" propagation="REQUIRED"/>
<tx:method name="get*" read-only="true"/>
<tx:method name="find*" read-only="true"/>
<tx:method name="*" propagation="REQUIRED"/>
tx:attributes>
tx:advice>
<aop:config>
<aop:pointcut id="pointcut" expression="execution(* com.ithubei.service.*.*(..))" />
<aop:advisor advice-ref="txAdvice" pointcut-ref="pointcut" />
aop:config>
<context:component-scan base-package="com.ithubei">context:component-scan>
beans>
实体类User.java
@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name = "user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Integer id;
@Column(name = "username")
private String name;
@Column(name = "password")
private String password;
@Column(name = "tel")
private String tel;
}
UserDao.java
package com.haoxuan.dao;
import com.haoxuan.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.Optional;
@Repository
public interface UserDao extends JpaRepository<User,Integer> {
public Optional<User> findById(Integer id);
}
测试类
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class SpringJpaTest {
@Autowired
UserDao userDao;
@Test
public void test1() {
Optional<User> user = userDao.findById(1);
if (user.isPresent()) {
System.out.println(user.get());
} else {
System.out.println("Not find!");
}
}
}