JPA之hibernate4.2.4之简单测试

jpa是sun官网提出的java持久层规范,但是它不是一个持久层产品,它的实现还需要持久层产品的支持,例如hibernate,toplink等orm产品.jpa与hibernate的关系,就例如jdbc与oracle的jdbc驱动实现一样,一个是接口、规范,一个是具体的实现.

现在利用jpa接口编程,利用hibernate作为底层实现,操作oracle 11g,实现简单的增删改查

1.新建一个java工程,名为JpaHibernateOracleTest,然后将需要的jar包拷贝到工程下,如下:

这个用到的jar包在官网下载包里面都有前面博客曾有介绍 http://blog.csdn.net/undergrowth/article/details/9963529 只是多了一个ojdbc6.jar 这个是连接oracle数据库需要用到的jar oracle官网也有http://www.oracle.com/technetwork/cn/database/enterprise-edition/jdbc-112010-094555-zhs.html

2.建立jpa的配置文件因为jpa在加载时默认会在类路径下的META-INF/ 目录下查找名为persistence.xml的配置文件进行加载

所以在src目录下新建META-INF文件夹然后在建立persistence.xml的文件

修改配置文件在下载hibernate的解压包里面 hibernate-release-4.2.4.Final\documentation\quickstart\en-US\html_single\index.html 里面就有关于jpa配置的模板还有一些其他的配置属性不清楚的查看前面博客有介绍http://blog.csdn.net/undergrowth/article/details/9963529

将persistence.xml配置文件修改如下:

<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="under">
        <properties>
        <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>
        <property name="hibernate.connection.username" value="under_test" />
         <property name="hibernate.connection.password" value="under_test" />
         <property name="hibernate.connection.url" value="jdbc:oracle:thin:@localhost:1521:ganew" />
         <property name="hibernate.hbm2ddl.auto" value="update" />
         <property name="hibernate.show_sql" value="true" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" />
        </properties>
    </persistence-unit>
</persistence>

目前hibernate 4.2.4只支持oracle10g 虽然我用的是oracle11g 但是这里写成10g 同样可以照常工作如果改成11g的话 hibernate不识别会报错

3.使用注解的方式编写实体类具体如下:

Student.java

package com.undergrowth;

import java.util.Date;

import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EnumType;
import javax.persistence.Enumerated;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Lob;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
//Entity表明Student类为一个实体类  Table的name属性用于指定生成的表名
@Entity  
@Table(name="studentInfo")
public class Student {
	//Id用于指定id属性为实体类的主键 
	//GeneratedValue用于表示主键自动产生 
	//因为连接的是oracle数据库 所以使用序列方式产生主键 
	@Id @GeneratedValue(strategy=GenerationType.SEQUENCE)
	private Integer id;
	//Column的length指定name字段可以容纳多少个字符 nullable表示不可以为空
	@Column(length=20,nullable=false)
	private String name;
	//以日期的格式建立该字段 
	@Temporal(TemporalType.DATE) @Column(nullable=false)
	private Date birthday;
	@Column(nullable=false)
	private Integer age;
	//EnumType.STRING表示存储的是枚举常量的字符串值
	@Enumerated(EnumType.STRING) @Column(nullable=false,length=8)
	private Gender sex;
	//Lob表示大字符对象  lazy使用延迟加载
	@Lob @Basic(fetch=FetchType.LAZY)
	private String describe;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public Gender getSex() {
		return sex;
	}
	public void setSex(Gender sex) {
		this.sex = sex;
	}
	public String getDescribe() {
		return describe;
	}
	public void setDescribe(String describe) {
		this.describe = describe;
	}
	//用于给反射使用
	public Student(){}
	public Student(String name, Date birthday, Integer age, Gender sex,
			String describe) {
		super();
		this.name = name;
		this.birthday = birthday;
		this.age = age;
		this.sex = sex;
		this.describe = describe;
	}
	
}

枚举类:

Gender.java

package com.undergrowth;

public enum Gender {
	男,女
}

4.建立junit测试代码

package com.junit;

import static org.junit.Assert.*;

import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.Test;

public class JunitTest {

	@Test
	public void test() {
		//通过配置文件中的<persistence-unit name="under">持久单元名,获取实体管理器工厂
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("under");
		//关闭实体管理器工厂
		factory.close();
	}

}

在test测试方法中加入以上两句话就可测试环境是否已经成功搭建并且建立表结构也是在创建实体管理器工厂的时候

如果没有问题在oracle数据库中应该看到studentinfo的表结构如下

产生主键的序列:

现在接着修改测试的test函数实现增删改查

修改如下:

添加记录

package com.junit;

import static org.junit.Assert.*;

import java.text.ParseException;
import java.text.SimpleDateFormat;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.Test;

import com.undergrowth.Gender;
import com.undergrowth.Student;

public class JunitTest {

	@Test
	public void test() {
		//通过配置文件中的<persistence-unit name="under">持久单元名,获取实体管理器工厂
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("under");
		//获取管理器实体
		EntityManager manager=factory.createEntityManager();
		
		
		try {
			addStudent(manager);
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//关闭管理器实体
		manager.close();
		//关闭实体管理器工厂
		factory.close();
	}

	private void addStudent(EntityManager manager) throws ParseException {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=new Student("undergrowth", new SimpleDateFormat("yyyy-MM-dd").parse("1999-1-2"), 20, Gender.男, "读书");
		manager.persist(student);
		//提交事务
		manager.getTransaction().commit();
	}

}

控制台输出:

Hibernate: select hibernate_sequence.nextval from dual
Hibernate: insert into studentInfo (age, birthday, name, sex, id, describe) values (?, ?, ?, ?, ?, ?)

通过控制台输出可以看到 hibernate底层使用了插入语句

oracle 数据效果

剩下的删除、更新、查询如下:

package com.junit;

import static org.junit.Assert.*;

import java.text.ParseException;
import java.text.SimpleDateFormat;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.Test;

import com.undergrowth.Gender;
import com.undergrowth.Student;

public class JunitTest {

	@Test
	public void test() {
		//通过配置文件中的<persistence-unit name="under">持久单元名,获取实体管理器工厂
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("under");
		//获取管理器实体
		EntityManager manager=factory.createEntityManager();
		
		
		/*try {
			addStudent(manager);
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}*/
		//调用更新
		updateStudent(manager);
		//关闭管理器实体
		manager.close();
		//关闭实体管理器工厂
		factory.close();
	}

	private void addStudent(EntityManager manager) throws ParseException {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=new Student("undergrowth", new SimpleDateFormat("yyyy-MM-dd").parse("1999-1-2"), 20, Gender.男, "读书");
		manager.persist(student);
		//提交事务
		manager.getTransaction().commit();
	}
	
	private Student selectStudent(EntityManager manager) {
		// TODO Auto-generated method stub
		//通过实体类的主键找到实体类
	   Student student=manager.find(Student.class, 270);
	   return student;
	}
	
	private void updateStudent(EntityManager manager)  {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=selectStudent(manager);
		student.setName("刘德华"); //处于事务管理关联并且实体类处于托管状态 才可以更新到数据库中
		//提交事务
		manager.getTransaction().commit();
	}

}

控制台输出:

Hibernate: select student0_.id as id1_0_0_, student0_.age as age2_0_0_, student0_.birthday as birthday3_0_0_, student0_.describe as describe4_0_0_, student0_.name as name5_0_0_, student0_.sex as sex6_0_0_ from studentInfo student0_ where student0_.id=?
Hibernate: update studentInfo set age=?, birthday=?, name=?, sex=?, describe=? where id=?

oracle 效果图:

删除:

package com.junit;

import static org.junit.Assert.*;

import java.text.ParseException;
import java.text.SimpleDateFormat;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.junit.Test;

import com.undergrowth.Gender;
import com.undergrowth.Student;

public class JunitTest {

	@Test
	public void test() {
		//通过配置文件中的<persistence-unit name="under">持久单元名,获取实体管理器工厂
		EntityManagerFactory factory=Persistence.createEntityManagerFactory("under");
		//获取管理器实体
		EntityManager manager=factory.createEntityManager();
		
		
		/*try {
			addStudent(manager);
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}*/
		//调用更新
		//updateStudent(manager);
		//删除
		deleteStudent(manager);
		//关闭管理器实体
		manager.close();
		//关闭实体管理器工厂
		factory.close();
	}

	private void addStudent(EntityManager manager) throws ParseException {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=new Student("undergrowth", new SimpleDateFormat("yyyy-MM-dd").parse("1999-1-2"), 20, Gender.男, "读书");
		manager.persist(student);
		//提交事务
		manager.getTransaction().commit();
	}
	
	private Student selectStudent(EntityManager manager) {
		// TODO Auto-generated method stub
		//通过实体类的主键找到实体类
	   Student student=manager.find(Student.class, 270);
	   return student;
	}
	
	private void updateStudent(EntityManager manager)  {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=selectStudent(manager);
		student.setName("刘德华"); //处于事务管理关联并且实体类处于托管状态 才可以更新到数据库中
		//提交事务
		manager.getTransaction().commit();
	}
	
	private void deleteStudent(EntityManager manager)  {
		// TODO Auto-generated method stub
		//打开事务
		manager.getTransaction().begin();
		Student student=selectStudent(manager);
		manager.remove(student); //处于事务管理关联并且实体类处于托管状态 才可以更新到数据库中
		//提交事务
		manager.getTransaction().commit();
	}


}

控制台:

Hibernate: select student0_.id as id1_0_0_, student0_.age as age2_0_0_, student0_.birthday as birthday3_0_0_, student0_.describe as describe4_0_0_, student0_.name as name5_0_0_, student0_.sex as sex6_0_0_ from studentInfo student0_ where student0_.id=?
Hibernate: delete from studentInfo where id=?

对于查询的话除了find以外还可使用getReference

对于更新与删除能够与数据库同步的原因在于

第一:实体对象处于实体对象管理器之下,即实体对象处于托管状态

第二: 实体管理器与事务关联

二者缺一实体对象都没有办法与数据库同步

以上即是jpa的简单实现记录学习的脚步好晚了睡觉了

posted on 2013-10-04 01:09 liangxinzhi 阅读(163) 评论(0) 编辑收藏举报

刷新页面返回顶部

liangxinzhi

JPA之hibernate4.2.4之简单测试

导航

公告