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https://en.wikibooks.org/wiki/Java_Persistence/What_is_JPA%3F
https://en.wikipedia.org/wiki/Java_Persistence_API
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表 CREATE TABLE `Employee` ( `id` int (11) unsigned NOT NULL , ` name ` varchar (20) DEFAULT NULL , `role` varchar (20) DEFAULT NULL , PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8; |
2.1項目結構
2.2 pom.xml
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使用了platform-bom,方便了包的依賴管理。
依賴樹結構
2.3 persistence.xml
<persistence version="2.1"
xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="JPAExamples">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
</persistence-unit>
</persistence>
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2.4 spring.xml
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<?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:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
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/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<!--數據源-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url" value="jdbc:mysql://localhost:3306/exampledb"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="persistenceXmlLocation" value="META-INF/persistence.xml"/>
<property name="persistenceUnitName" value="JPAExamples"/>
<property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
<property name="jpaDialect" ref="jpaDialect"/>
<property name="jpaProperties">
<props>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean>
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="generateDdl" value="false" />
<property name="database" value="MYSQL"/>
</bean>
<bean id="jpaDialect" class="org.springframework.orm.jpa.vendor.HibernateJpaDialect"/>
<bean id="entityManager" factory-bean="entityManagerFactory" factory-method="createEntityManager"></bean>
<!-- Jpa 事務管理器 -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"
p:entityManagerFactory-ref="entityManagerFactory" />
<!-- 開啓註解事務 -->
<tx:annotation-driven transaction-manager="transactionManager" proxy-target-class="true" />
<!-- 啓動對@AspectJ(面向切面)註解的支持 -->
<aop:aspectj-autoproxy />
<context:component-scan base-package="com.journaldev.spring.jpa"></context:component-scan>
</beans>
有的對象,不是必須的。爲了保持完整性,做了保留。
可以配置entityManagerFactory的packagesToScan屬性,沒有配置也是可以的。
2.5 entity
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package com.journaldev.spring.jpa.model;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Employee {
@Id
private int id;
private String name;
private String role;
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 getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
@Override
public String toString() {
return "{ID=" + id + ",Name=" + name + ",Role=" + role + "}";
}
}
2.6 接口
public interface EmployeeDAO {
//Create
public void save(Employee employee);
//Read
public Employee getById(int id);
//Update
public void update(Employee employee);
//Delete
public void deleteById(int id);
//Get All
public List<Employee> getAll();
}
package com.journaldev.spring.jpa.dao;
import com.journaldev.spring.jpa.model.Employee;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.transaction.Transactional;
import java.util.List;
/**
* Created by zhaoguoyu on 2016/6/22.
*/
@Transactional
@Repository
public class EmployeeDAOImpl implements EmployeeDAO {
@PersistenceContext
EntityManager em;
@Override
public void save(Employee employee) {
em.persist(employee);
}
@Override
public Employee getById(int id) {
return em.find(Employee.class, id);
}
public void update(Employee employee) {
em.merge(employee);
}
@Override
public void deleteById(int id) {
em.remove(this.getById(id));
}
@Override
public List<Employee> getAll() {
CriteriaBuilder builder =em.getCriteriaBuilder();
final CriteriaQuery<Employee> query = builder.createQuery(Employee.class);
return this.em.createQuery(query).getResultList();
}
}
2.7測試
測試類
import com.journaldev.spring.jpa.dao.EmployeeDAO;
import com.journaldev.spring.jpa.model.Employee;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import javax.annotation.Resource;
import java.util.Random;
/**
* Created by zhaoguoyu on 2016/6/22.
*/
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:spring.xml")
public class SpringJPATest extends AbstractTransactionalJUnit4SpringContextTests {
@Resource
private EmployeeDAO employeeDAO;
@Test
public void testSave(){
Employee emp = new Employee();
int rand = new Random().nextInt(1000);
emp.setId(rand);
emp.setName("Pankaj");
emp.setRole("Java Developer");
employeeDAO.save(emp);
}
@Test
public void testUpdate(){
Employee emp = new Employee();
int rand = new Random().nextInt(1000);
emp.setId(rand);
emp.setName("Pankaj");
emp.setRole("Java Developer");
employeeDAO.save(emp);
emp.setName(emp.getName()+"_update");
employeeDAO.update(emp);
}
}
OR
import com.journaldev.spring.jpa.dao.EmployeeDAO;
import com.journaldev.spring.jpa.model.Employee;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.Random;
/**
* Created by zhaoguoyu on 2016/6/22.
*/
public class Main {
public static void main(String[] args) {
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring.xml");
final EmployeeDAO employeeDAO = ctx.getBean(EmployeeDAO.class);
Employee emp = new Employee();
int rand = new Random().nextInt(1000);
emp.setId(rand);
emp.setName("Pankaj");
emp.setRole("Java Developer");
employeeDAO.save(emp);
Employee employee = employeeDAO.getById(rand);
employee.setName(employee.getName() +"_update");
employeeDAO.update(employee);
}
}
有一點需要說明。默認使用的日誌是logback.號稱比log4j更優秀的一款。
默認的日誌配置logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<layout class="ch.qos.logback.classic.PatternLayout">
<Pattern>
%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
</Pattern>
</layout>
</appender>
<logger name="org.hibernate" level="debug" additivity="false">
<appender-ref ref="STDOUT" />
</logger>
<root level="error">
<appender-ref ref="STDOUT" />
</root>
</configuration>
總結
本文主要講解了Spring對JPA的支持,和演示了整合過程。其中JPA的內容還有很多,不可能在本文全部講完。本系列主要是爲大家提供以遞進的方式,通過前後的演示對比,感覺Spring DATA API的強大。
通過JPA的整合,實現了訪問數據庫,完全不需要寫SQL。這樣的好處之一:實現了SQL的透明,可以無縫實現不同數據庫廠商和數據庫版本間的切換。Spring 對JPA的支持還沒有結束
本文出自 “簡單” 博客,請務必保留此出處http://dba10g.blog.51cto.com/764602/1791946