Hibernate一对多双向关联

一种商品类别下有多个商品，多个商品对应同一个商品类别,这种关系就是一对多双向关联。

 

商品类：

package com.pojo;/** * Product entity. * * @author MyEclipse Persistence Tools */public class Product implements java.io.Serializable {private static final long serialVersionUID = -7963752710605063544L;private int id;private String productname;private String remark;// 多对一private Category category;public int getId() {return id;}public void setId(int id) {this.id = id;}public Category getCategory() {return category;}public void setCategory(Category category) {this.category = category;}public Product() {}public String getProductname() {return this.productname;}public void setProductname(String productname) {this.productname = productname;}public String getRemark() {return this.remark;}public void setRemark(String remark) {this.remark = remark;}}

 

商品类别：

package com.pojo;import java.util.HashSet;import java.util.Set;/** * Category entity. * * @author MyEclipse Persistence Tools */public class Category implements java.io.Serializable {private static final long serialVersionUID = -666185106951167028L;private int id;private String name;private String mark;// 集合，一对多private Set<Product> products = new HashSet<Product>();public int getId() {return id;}public void setId(int id) {this.id = id;}public Set<Product> getProducts() {return products;}public void setProducts(Set<Product> products) {this.products = products;}public Category() {}public String getName() {return this.name;}public void setName(String name) {this.name = name;}public String getMark() {return this.mark;}public void setMark(String mark) {this.mark = mark;}}

 

XML配置文件，一对多的关系：

<?xml version="1.0" encoding="utf-8"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><!-- Mapping file autogenerated by MyEclipse Persistence Tools--><hibernate-mapping> <class name="com.pojo.Category" table="CATEGORY" schema="ZM"> <id name="id" type="java.lang.Integer"> <column name="ID" precision="8" scale="0" /> <generator class="increment" /> </id> <property name="name" type="java.lang.String"> <column name="NAME" length="100" /> </property> <property name="mark" type="java.lang.String"> <column name="MARK" length="100" /> </property> <!-- 一对多，一种商品类型有多个商品 --> <set name="products" cascade="all" outer-join="true"> <key column="producttypeid" foreign-key="id"></key> <one-to-many class="com.pojo.Product" /> </set> </class></hibernate-mapping>

 

多个商品对应一个商品类别：

 

<?xml version="1.0" encoding="utf-8"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><!-- Mapping file autogenerated by MyEclipse Persistence Tools--><hibernate-mapping> <class name="com.pojo.Product" table="PRODUCT" schema="ZM"> <id name="id" type="java.lang.Integer"> <column name="ID" precision="8" scale="0" /> <generator class="increment" /> </id> <property name="productname" type="java.lang.String"> <column name="PRODUCTNAME" length="100" /> </property> <property name="remark" type="java.lang.String"> <column name="REMARK" length="100" /> </property> <!-- 多对一，多个商品对应一个分类 --> <many-to-one name="category" class="com.pojo.Category" outer-join="true" > <column name="producttypeid"></column> </many-to-one> </class></hibernate-mapping>

 

 

测试类：

 

package com.test;import java.util.List;import java.util.Set;import org.hibernate.Session;import com.pojo.Category;import com.pojo.Product;import com.util.HibernateManager;public class Test1 {/** * beckham Dec 14, 2009 7:30:06 PM */public static void main(String[] args) {Test1.delete();}public static void addType() {Session session = HibernateManager.openSession();Category c = new Category();c.setName("电脑");c.setMark("这是电脑类别");try {session.save(c);HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}public static void addPro() {Session session = HibernateManager.openSession();// 获取类型Category c = (Category) session.load(Category.class, new Integer(1));// 商品1Product p = new Product();p.setProductname("摩托罗拉v8");p.setRemark("很好的手机");// 商品2Product p1 = new Product();p1.setProductname("摩托罗拉A1200");p1.setRemark("非常好的手机");// 一对多关联Set<Product> set = c.getProducts();set.add(p);set.add(p1);// 直接保存商品类别，商品自动级联就保存session.save(c);try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}public static void loadPro() {Session session = HibernateManager.openSession();Product p = (Product) session.load(Product.class, new Integer(1));System.out.println("类别编号:" + p.getCategory().getId());System.out.println("类别名称:" + p.getCategory().getName());System.out.println("类别描述:" + p.getCategory().getMark());System.out.println("商品编号" + p.getId());System.out.println("商品名称:" + p.getProductname());System.out.println("商品描述：" + p.getRemark());try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}@SuppressWarnings("unchecked")public static void loadProList() {Session session = HibernateManager.openSession();// 先获取类型List<Product> list = session.createQuery("from Product").list();for (Product p : list) {System.out.println("类别编号:" + p.getCategory().getId());System.out.println("类别名称:" + p.getCategory().getName());System.out.println("类别描述:" + p.getCategory().getMark());System.out.println("商品编号" + p.getId());System.out.println("商品名称:" + p.getProductname());System.out.println("商品描述：" + p.getRemark());System.out.println("<br/>");}try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}// 修改商品类型，级联操作public static void updateCate() {Session session = HibernateManager.openSession();Category c = (Category) session.load(Category.class, new Integer(1));Set<Product> products = c.getProducts();for (Product p : products) {if (p.getId() == 1) {p.setProductname("诺基亚6300");p.setRemark("very good");}}session.update(c);try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}// 修改商品类型，级联操作public static void updatePro() {Session session = HibernateManager.openSession();Product p = (Product) session.load(Product.class, new Integer(1));Category c = p.getCategory();p.setProductname("三星");p.setRemark("很实用的手机");session.update(c);try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}// 删除某一类别，并级联删除该类别下面的所有商品public static void delete() {Session session = HibernateManager.openSession();Category c = (Category) session.load(Category.class, new Integer(1));//级联删除session.delete(c);try {HibernateManager.closeSession();} catch (Exception e) {e.printStackTrace();HibernateManager.rollbackTransaction();}}}