Spring整合JPA

缺乏、安全感 2022-03-30 14:00 278阅读 0赞

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>           **今天，来写一遍Spring整合JPA的Demo，Spring框架呢 是我们学习JavaWeb必学的一个框架，非常好用，而且支持对第三方框架的集成，所以在JavaWeb项目中用的比较多。JPA呢是Java Persistence API的简称，中文名:Java持久层API，是JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体[对象持久化][Link 1]到数据库中。JPA的出现使的我们的ORM映射更加便捷，清晰。废话不多说，开工！！！**

## 一、搭建环境 ##

*  创建Java工程的目录结构(Demo选择Java工程即可)

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70][]

*  编写Spring的配置文件

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xmlns:context="http://www.springframework.org/schema/context"
    	xmlns:tx="http://www.springframework.org/schema/tx"
    	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
    		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
    	
    	
    	<context:component-scan base-package="com.nyist.SpingUnionJPA"></context:component-scan>
    	
    	
    	<context:property-placeholder location="classpath:db.properties"/>
    	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
    		<property name="user" value="${jdbc.username}"></property>
    		<property name="password" value="${jdbc.password}"></property>
    		<property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
    		<property name="driverClass" value="${jdbc.driverClass}"></property>
    		
    	</bean>
    	
    	
    	<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    		
    		<property name="dataSource" ref="dataSource"></property>
    		
    		<property name="jpaVendorAdapter">
    			<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"></bean>
    		</property>
    		
    		
    		<property name="packagesToScan" value="com.nyist.SpingUnionJPA.Entity"></property>
    		
    		
    		<property name="jpaProperties">
    			<props>
    				<prop key="hibernate.show_sql">true</prop>
    				<prop key="hibernate.format_sql">true</prop>
    				<prop key="hibernate.hbm2ddl.auto">update</prop>
    			</props>
    		</property>
    	</bean>
    	
    	
    	<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    		<property name="entityManagerFactory" ref="entityManagerFactory"></property>
    	</bean>
    	
    	
    	<tx:annotation-driven transaction-manager="transactionManager"/>	
    </beans>

*  db.properties

> jdbc.username=root  
> jdbc.password=root  
> jdbc.jdbcUrl=jdbc:mysql:///jpa  
> jdbc.driverClass=com.mysql.jdbc.Driver

*  导入Jar包

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70 1][]

## 二、完善工程结构 ##

### 1.编写实体类 ###

>  *  在Entity包下创建Person实体类，内容如下：
> 
>     package com.nyist.SpingUnionJPA.Entity;
>     
>     import javax.persistence.Column;
>     import javax.persistence.Entity;
>     import javax.persistence.GeneratedValue;
>     import javax.persistence.GenerationType;
>     import javax.persistence.Id;
>     import javax.persistence.Table;
>     /**
>     *  至于 这些注解  什么意思   大家可以参考我的上一篇关于JPA的博客   SpingData整合JPA  在这个博客有详细解释
>     */
>     @Table(name="jpa_person")
>     @Entity
>     public class Person {
>     
>     	@GeneratedValue(strategy=GenerationType.AUTO)
>     	@Id
>     	@Column(length=10,unique=true,nullable=false)
>     	private Integer id;
>     	@Column(name="last_name",length=255)
>     	private String lastName;
>     	@Column(name="email",length=255)
>     	private String email;
>     	@Column(name="age",length=11,nullable=false)
>     	private Integer age;
>     	public Integer getId() {
>     		return id;
>     	}
>     	public void setId(Integer id) {
>     		this.id = id;
>     	}
>     	public String getLastName() {
>     		return lastName;
>     	}
>     	public void setLastName(String lastName) {
>     		this.lastName = lastName;
>     	}
>     	public String getEmail() {
>     		return email;
>     	}
>     	public void setEmail(String email) {
>     		this.email = email;
>     	}
>     	public Integer getAge() {
>     		return age;
>     	}
>     	public void setAge(Integer age) {
>     		this.age = age;
>     	}
>     	public Person(Integer id, String lastName, String email, Integer age) {
>     		super();
>     		this.id = id;
>     		this.lastName = lastName;
>     		this.email = email;
>     		this.age = age;
>     	}
>     	public Person() {
>     		super();
>     	}
>     	@Override
>     	public String toString() {
>     		return "Person [id=" + id + ", lastName=" + lastName + ", email=" + email + ", age=" + age + "]";
>     	}
>     	
>     	
>     }
> 
>

### 2.创建Dao层 ###

>  *  创建PersonDao.java 文件，内容如下：
> 
>     package com.nyist.SpingUnionJPA.Dao;
>     
>     import javax.persistence.EntityManager;
>     import javax.persistence.PersistenceContext;
>     import org.springframework.stereotype.Repository;
>     import com.nyist.SpingUnionJPA.Entity.Person;
>     //@Repository  将PersonDao 交给Spring容器管理  注入到容器中去
>     @Repository
>     public class PersonDao {
>     	
>     	/**
>     	 * 如何获取和当前事务关联的EntityManager 对象呢？
>     	 * 通过 @PersistenceContext
>     	 */
>     	//注入 EntityManagerFactory
>     	@PersistenceContext
>     	private  EntityManager entityManager;
>     	
>     	public void save(Person person){
>     		entityManager.persist(person);
>     	}
>     }
> 
>

### 4.编写Service层 ###

>  *  创建PersonService.java文件，内容如下：
> 
>     package com.nyist.SpingUnionJPA.Service;
>     
>     import org.springframework.beans.factory.annotation.Autowired;
>     import org.springframework.stereotype.Service;
>     import org.springframework.transaction.annotation.Transactional;
>     
>     import com.nyist.SpingUnionJPA.Dao.PersonDao;
>     import com.nyist.SpingUnionJPA.Entity.Person;
>     
>     @Service
>     public class PersonService {
>     	
>     	@Autowired
>     	private PersonDao personDao;
>     	
>     	@Transactional
>     	public void savePerson(Person person1,Person person2){
>     		personDao.save(person1);
>     		personDao.save(person2);
>     	}
>     }
> 
>

### 5.测试 ###

>  *  测试类如下：
> 
>     package com.nyist.SpingUnionJPA.Test;
>     
>     import org.junit.Before;
>     import org.junit.Test;
>     import org.springframework.context.ApplicationContext;
>     import org.springframework.context.support.ClassPathXmlApplicationContext;
>     
>     import com.mchange.v2.c3p0.ComboPooledDataSource;
>     import com.nyist.SpingUnionJPA.Entity.Person;
>     import com.nyist.SpingUnionJPA.Service.PersonService;
>     
>     
>     public class TestJPA {
>     
>     	private PersonService personService = null;
>     	private ApplicationContext ctx = null;
>     	@Before
>     	public void before(){
>     		ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
>     		personService = ctx.getBean(PersonService.class);
>     	}
>     	
>     	@Test
>     	public void testJPA(){
>     		ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
>     		ComboPooledDataSource dataSource = (ComboPooledDataSource)ctx.getBean("dataSource");
>     		System.out.println(dataSource);
>     	}
>     	
>     	
>     	@Test
>     	public void testPersonService(){
>     		Person person1 = new Person();
>     		person1.setAge(12);
>     		person1.setEmail("qq@qq.com");
>     		person1.setLastName("NiHao");
>     		
>     		Person person2 = new Person();
>     		person2.setAge(13);
>     		person2.setEmail("QQ@qq.com");
>     		person2.setLastName("Hello World ");
>     		personService.savePerson(person1, person2);
>     	}
>     	
>     }
> 
>

### 6.结果 ###

![20190106153847700.png][]

![20190106153815339.png][]

### 7.项目结构 ###

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70 2][]

### 8.源码下载：[下载][Link 2] ###

[Link 1]: https://baike.baidu.com/item/%E5%AF%B9%E8%B1%A1%E6%8C%81%E4%B9%85%E5%8C%96/7316192
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70]: /images/20220330/3951bdf8dd5d4d50901bb968f6823473.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70 1]: /images/20220330/04d927e1e74a4913975898cdd7152c3b.png
[20190106153847700.png]: /images/20220330/ae47d56370254b5085911a063e99e978.png
[20190106153815339.png]: /images/20220330/77d339252e3746f99bfd9a21c3aee5f2.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x2aGFvZ3Vhbmcw_size_16_color_FFFFFF_t_70 2]: /images/20220330/0c6ccaff3b57426e974951b02b04c47f.png
[Link 2]: https://download.csdn.net/download/lvhaoguang0/10899345