JPA相关课程代码

最新推荐文章于 2025-06-07 10:30:00 发布

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完整测试项目可在这里下载：http://download.youkuaiyun.com/detail/liangrui1988/6542729

部分代码：

META-INF

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<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_1_0.xsd"
   version="1.0">
   <persistence-unit name="rui" transaction-type="RESOURCE_LOCAL">
   <!--  全局事务配置
      <jta-data-source>java:/DefaultDS</jta-data-source> -->
      <properties>
        <!-- hibernate config org.hibernate.dialect.HSQLDialect
        org.hibernate.dialect.MySQLDialect
        -->
         <property name="hibernate.dialect" value="org.hibernate.dialect.OracleDialect"/>
         <property name="hibernate.hbm2ddl.auto" value="update"/>
         <property name="show_sql" value="true"/>         
 
         <!-- database config -->
         <property name="hibernate.connection.driver_class" value="oracle.jdbc.driver.OracleDriver"/>
         <property name="hibernate.connection.username" value="juxun"/>
         <property name="hibernate.connection.password" value="rui"/>
         <property name="hibernate.connection.url" value="jdbc:oracle:thin:@127.0.0.1:1521:ABC"/>
         
      
       <!--   <property name="hibernate.max_fetch_depth" value="3"/> -->
       
      </properties>
   </persistence-unit>
</persistence>

ManyToMany

package com.rui.ManyToMany;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;

import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Parameter;

@Entity
@GenericGenerator(name = "stuId", strategy = "sequence",parameters=@Parameter(name="sequence",value="preson_id"))
public class Student {
	
	private Integer id;
	private String name;
	private Set<Teacher> teacher=new HashSet<Teacher>();
	
	
	@Id
	@GeneratedValue(generator="stuId")
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	@ManyToMany(cascade={CascadeType.REFRESH})
	//@JoinTable(name="stu_tea")
	@JoinTable(name="stu_tea",inverseJoinColumns=@JoinColumn(name="tea_id")
	,joinColumns=@JoinColumn(name="stu_id"))
	public Set<Teacher> getTeacher() {
		return teacher;
	}
	
	public void setTeacher(Set<Teacher> teacher) {
		this.teacher = teacher;
	}
	
	//添加学生和老师的关系	
	public void addTeacher(Teacher te){
		this.teacher.add(te);		
	}	
	//解除学生跟老师的关系
	public void removeTeacher(Teacher te){
		if(this.teacher.contains(te)){
			this.teacher.remove(te);
		}
	}
	

}

package com.rui.ManyToMany;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;

import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Parameter;

@Entity
@GenericGenerator(name = "teaId", strategy = "sequence",parameters=@Parameter(name="sequence",value="preson_id"))
public class Teacher {
	
	private Integer id;
	private  String name;	
	private Set<Student> student=new HashSet<Student>();
	
	@Id
	@GeneratedValue(generator="teaId")
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	@Column(length=10,nullable=false)
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	//被维护端 mappedBy  (Teacher)老师被学生维护 (Student)
	@ManyToMany(cascade={CascadeType.REFRESH},mappedBy="teacher")
	public Set<Student> getStudent() {
		return student;
	}
	public void setStudent(Set<Student> student) {
		this.student = student;
	}
	
	
	//为hash分区
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((id == null) ? 0 : id.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Teacher other = (Teacher) obj;
		if (id == null) {
			if (other.id != null)
				return false;
		} else if (!id.equals(other.id))
			return false;
		return true;
	}
	
	
	
	

}

package com.rui.ManyToMany;

import static org.junit.Assert.*;

import java.util.HashSet;
import java.util.Set;

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

import org.junit.Test;

import com.rui.ManyToOne.Order;
import com.rui.ManyToOne.OrderItem;

public class ManyToManyTest {

	@Test
	public void test() {
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
		 EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();
			
			Teacher te=new Teacher();
			te.setName("刘老师");
			Teacher te2=new Teacher();
			te.setName("李老师");
			em.persist(te);
			//给学生分两个老师
			Student stu=new Student();
			stu.setName("小明");
			//stu.getTeacher().add(te);//学生加老师
			//stu.getTeacher().add(te2);
			
			em.persist(stu);//保存学生
			
			em.getTransaction().commit();
			
			em.close();
			emf.close();
		System.out.println("ok....");
	}
	
	
	/**
	 * 建立关系
	 */
	@Test
	public void addRe(){
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
		 EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();
		
		Student st=em.find(Student.class,46);//获取一个学生
		
		//刷新对象 获得老师 并建立关系
		st.addTeacher(em.getReference(Teacher.class,47));
		
		em.getTransaction().commit();
		
		em.close();
		emf.close();
	System.out.println("ok....");
	}
	
	
	/**
	 * 删除关系
	 */
	@Test
	public void removeRe(){
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
		 EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();		
		Student st=em.find(Student.class,46);//获取一个学生		
		st.removeTeacher(em.getReference(Teacher.class,45));//刷新对象 并建立关系		
		em.getTransaction().commit();		
		em.close();
		emf.close();
	System.out.println("ok....");
	}

	
	/**
	 * 删除老师
	 */
	@Test
	public void deleteTeacher(){
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
		 EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();
		//先解除关系才能删除老师		
		Student st=em.find(Student.class,46);//获取一个学生			
		st.removeTeacher(em.getReference(Teacher.class,45));
		//删除老师
		em.remove(em.getReference(Teacher.class,45));	
		em.getTransaction().commit();		
		em.close();
		emf.close();
	System.out.println("ok....");
	}
	
	
	

	/**
	 * 删除学生
	 */
	@Test
	public void deleteStudent(){
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
		 EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();
		
		Student st=em.find(Student.class,46);//获取一个学生			
		
		//删除 学生 关系维护端 有权利操作外健
		em.remove(st);	
		em.getTransaction().commit();		
		em.close();
		emf.close();
	System.out.println("ok....");
	}
}

ManyToOne

==========================================

package com.rui.ManyToOne;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;

@Entity
public class OrderItem {
	
	private Integer id;
	private String productName;//产品名称
	private Float sellPrice;//销售价格
	private Order order;//订单
	
	@Id
	//@Column(name="ids",length=8)
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getProductName() {
		return productName;
	}
	public void setProductName(String productName) {
		this.productName = productName;
	}
	public Float getSellPrice() {
		return sellPrice;
	}
	public void setSellPrice(Float sellPrice) {
		this.sellPrice = sellPrice;
	}
	//optional =true 可选 ，存放的值可以为null(外健)
	@ManyToOne(cascade={CascadeType.REFRESH,CascadeType.MERGE}
	,optional=false)
	@JoinColumn(name="order_id") //关联字段  外健id
	public Order getOrder() {
		return order;
	}
	public void setOrder(Order order) {
		this.order = order;
	}
	
	

}

package com.rui.ManyToOne;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name="orders")
public class Order {
	private String orderId;
	private Float amount;
	private Set<OrderItem> item=new HashSet<OrderItem>();
	
	@Id
	@Column(name="order_id",length=8)
	public String getOrderId() {
		return orderId;
	}
	public void setOrderId(String orderId) {
		this.orderId = orderId;
	}
	@Column(nullable=false)
	public Float getAmount() {
		return amount;
	}
	public void setAmount(Float amount) {
		this.amount = amount;
	}
	/**
	 * alter table OrderItem
	 * add constraint pk_order foreign key order
	 * reference order(orderId)
	 * 一个订单对应多个订单项
	 * 多个订单项对应一个订单
	 * @return
	 */
	//那个类出现了mappedBy 就是关系被维护端  
	//order 指定这个属性来维据关系 
	@OneToMany(cascade={CascadeType.REFRESH,CascadeType.PERSIST,CascadeType.MERGE,CascadeType.REMOVE}
	 ,fetch=FetchType.LAZY,mappedBy="order")
	public Set<OrderItem> getItem() {
		return item;
	}
	public void setItem(Set<OrderItem> item) {
		this.item = item;
	}
	
	public void addOrderItem(OrderItem oi){
		
		oi.setOrder(this);//送来的订单项对象里加入 订单
		this.item.add(oi);//添加订单   里的订单项
	}
	
	
	
	
	

}

package com.rui.ManyToOne;

import static org.junit.Assert.*;

import java.util.UUID;

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

import org.junit.Test;

public class OneToManyTest {
	@Test
	public void test() {
		EntityManagerFactory emf=Persistence.createEntityManagerFactory("rui");
	  EntityManager em= emf.createEntityManager(); 
		em.getTransaction().begin();
		
		Order order=new Order();
		order.setOrderId("888");//UUID.randomUUID().toString()
		order.setAmount(90F);
		
		OrderItem oi=new OrderItem();
		oi.setId(20);
		oi.setProductName("ipone");
		oi.setSellPrice(5888F);
		//oi.setOrder(order);
		
		OrderItem oi2=new OrderItem();
		oi2.setId(21);
		oi2.setProductName("ipone6");
		oi2.setSellPrice(6888F);
		
		//订单里加入订单项
		order.addOrderItem(oi);
		order.addOrderItem(oi2);
		//插入订单
		em.persist(order);
		em.getTransaction().commit();
		
		emf.close();
	System.out.println("ok....");
	}

}

==================

复合主健

package com.rui.compositePK;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;

@Entity
public class AriLine {
	
	private AriLinePK id;//这里把复合主健看成一个整体 用一个类来描述它
	private String name;
	
	
	public AriLine(){}
	
	public AriLine(String stratCity,String endCity,String name){
		this.id=new AriLinePK(stratCity,endCity);
        this.name=name;		
	}
	
	@EmbeddedId //可嵌入的类 id
	public AriLinePK getId() {
		return id;
	}
	public void setId(AriLinePK id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
	
	
	

}