《hibernate的一对多的关系》

淡淡的烟草味﹌ 2022-04-12 13:58 173阅读 0赞

**1.entity**

package com.zy.three.entity;
    
    import java.util.HashSet;
    import java.util.Set;
    
    public class Order {
    	
    //	order_id int primary key auto_increment,
    //	order_no varchar(50) not null
    	
    	private Integer order_id;
    	private String order_no;
    	
    	private Set<OrderItem> orderItem = new HashSet<>();
    	
    	private Integer initOrderItem = 0; //0:代表懒加载，1:代表强制加载
    	
    	public Set<OrderItem> getOrderItem() {
    		return orderItem;
    	}
    	public void setOrderItem(Set<OrderItem> orderItem) {
    		this.orderItem = orderItem;
    	}
    	
    	public Integer getInitOrderItem() {
    		return initOrderItem;
    	}
    	public void setInitOrderItem(Integer initOrderItem) {
    		this.initOrderItem = initOrderItem;
    	}
    	
    	public Integer getOrder_id() {
    		return order_id;
    	}
    	public void setOrder_id(Integer order_id) {
    		this.order_id = order_id;
    	}
    	public String getOrder_no() {
    		return order_no;
    	}
    	public void setOrder_no(String order_no) {
    		this.order_no = order_no;
    	}
    	
    	public Order() {
    		super();
    	}
    	public Order(Integer order_id, String order_no) {
    		super();
    		this.order_id = order_id;
    		this.order_no = order_no;
    	}
    	
    	@Override
    	public String toString() {
    		return "Order [order_id=" + order_id + ", order_no=" + order_no + "]";
    	}
    	
    
    }

package com.zy.three.entity;
    
    public class OrderItem {
    	
    //	  order_item_id int primary key auto_increment,
    //	  product_id int not null,
    //	  quantity int not null,
    //	  oid int not null,
    	
    	private Integer order_item_id;
    	private Integer product_id;
    	private Integer quantity;
    	private Integer oid;
    	
    	private Order order;
    	
    	public Order getOrder() {
    		return order;
    	}
    	public void setOrder(Order order) {
    		this.order = order;
    	}
    	
    	public Integer getOrder_item_id() {
    		return order_item_id;
    	}
    	public void setOrder_item_id(Integer order_item_id) {
    		this.order_item_id = order_item_id;
    	}
    	public Integer getProduct_id() {
    		return product_id;
    	}
    	public void setProduct_id(Integer product_id) {
    		this.product_id = product_id;
    	}
    	public Integer getQuantity() {
    		return quantity;
    	}
    	public void setQuantity(Integer quantity) {
    		this.quantity = quantity;
    	}
    	public Integer getOid() {
    		return oid;
    	}
    	public void setOid(Integer oid) {
    		this.oid = oid;
    	}
    	
    	public OrderItem() {
    		super();
    	}
    	public OrderItem(Integer order_item_id, Integer product_id, Integer quantity, Integer oid) {
    		super();
    		this.order_item_id = order_item_id;
    		this.product_id = product_id;
    		this.quantity = quantity;
    		this.oid = oid;
    	}
    	
    	@Override
    	public String toString() {
    		return "OrderItem [order_item_id=" + order_item_id + ", product_id=" + product_id + ", quantity=" + quantity + ", oid=" + oid + "]";
    	}
    	
    
    }

**2.entity.hbm.xml**

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping>
        
    	<class name="com.zy.three.entity.Order" table="t_hibernate_order">
    	    
    		<id name="order_id" type="java.lang.Integer" column="order_id">
    		    
    			<generator class="increment"/> 
    		</id>
    		
    		
    		<property name="order_no" type="java.lang.String" column="order_no"></property>
    		
    		
    		<set name="orderItem" cascade="save-update" inverse="true">
    		     <key column="oid"></key>
    		     <one-to-many class="com.zy.three.entity.OrderItem"/>
    		</set>
    		
    	</class>
    </hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE hibernate-mapping PUBLIC 
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <hibernate-mapping>
        
    	<class name="com.zy.three.entity.OrderItem" table="t_hibernate_order_item">
    	    
    		<id name="order_item_id" type="java.lang.Integer" column="order_item_id">
    		    
    			<generator class="increment"/> 
    		</id>
    		
    		
    		<property name="product_id" type="java.lang.Integer" column="product_id"></property>
    		<property name="quantity" type="java.lang.Integer" column="quantity"></property>
    		<property name="oid" type="java.lang.Integer" column="oid"></property>
    		
    		
    		
    		<many-to-one name="order" class="com.zy.three.entity.Order" insert="false" update="false" column="oid"></many-to-one>
    		
    	</class>
    </hibernate-mapping>

**3.hibernate.cfg.xml**

<mapping resource="com/zy/three/entity/Order.hbm.xml"/>
    		<mapping resource="com/zy/three/entity/OrderItem.hbm.xml"/>

**4.dao**

package com.zy.three.dao;
    
    import java.util.List;
    
    import org.hibernate.Hibernate;
    import org.hibernate.Session;
    import org.hibernate.Transaction;
    
    import com.zy.three.entity.Order;
    import com.zy.three.entity.OrderItem;
    import com.zy.two.util.SessionFactoryUtil;
    
    public class OrderDao {
    	
    	/**
    	 * 增加订单方法
    	 * @param order
    	 */
    	public void addOrder(Order order) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		session.save(order); //操作数据库
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    	}
    	
    	/**
    	 * 查询
    	 * @param order
    	 * @return
    	 */
    	public Order get(Order order) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		Order os = session.get(Order.class, order.getOrder_id()); //操作数据库
    		
    		//如果查询订单的数据不为空，并且设置的是强制加载（0:代表懒加载，1:代表强制加载）
    		if(os != null && new Integer(1).equals(order.getInitOrderItem())) {
    			Hibernate.initialize(os.getOrderItem()); //强制加载第二张表的数据（订单项表）
    		}
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    		return os;
    	}
    	
    	/**
    	 * 查询所有
    	 * @return
    	 */
    	public List<Order> OrderList(Order order) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		List<Order> oList = session.createQuery("from Order").list(); //操作数据库
    		for (Order o : oList) {
    			//如果查询订单的数据不为空，并且设置的是强制加载（0:代表懒加载，1:代表强制加载）
    			if(o != null && new Integer(1).equals(order.getInitOrderItem())) {
    				Hibernate.initialize(o.getOrderItem()); //强制加载第二张表的数据（订单项表）
    			}
    		}
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    		return oList;
    	}
    	
    	/**
    	 * 删除
    	 * @param order
    	 */
    	public void delete(Order order) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		
    		Order os = session.get(Order.class, order.getOrder_id()); //操作数据库
    		for (OrderItem oi : os.getOrderItem()) {
    			session.delete(oi);
    		}
    		session.delete(os);
    		
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    	}
    	
    }

package com.zy.three.dao;
    
    import org.hibernate.Session;
    import org.hibernate.Transaction;
    
    import com.zy.three.entity.OrderItem;
    import com.zy.two.util.SessionFactoryUtil;
    
    public class OrderItemDao {
    	
    	/**
    	 * 增加订单项方法
    	 * @param order
    	 */
    	public void addOrderItem(OrderItem orderItem) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		session.save(orderItem); //操作数据库
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    	}
    	
    	/**
    	 * 查询订单项
    	 * @param orderItem
    	 * @return
    	 */
    	public OrderItem get(OrderItem orderItem) {
    		Session session = SessionFactoryUtil.getSession(); //获取session会话
    		Transaction transaction = session.beginTransaction(); //开启事物
    		OrderItem ois = session.get(OrderItem.class, orderItem.getOrder_item_id()); //操作数据库
    		transaction.commit(); //提交事物
    		session.close(); //关闭会话
    		return ois;
    	}
    
    }

**5.daoTest**

package com.zy.three.dao;
    
    import static org.junit.Assert.*;
    
    import java.util.List;
    
    import org.junit.Test;
    
    import com.zy.three.entity.Order;
    
    public class OrderDaoTest {
    	
    	private OrderDao orderDao = new OrderDao();
    	
    	/**
    	 * 增加订单
    	 */
    	@Test
    	public void addOrder() {
    		Order order = new Order();
    		order.setOrder_no("zyj");
    		orderDao.addOrder(order);
    	}
    
    	/**
    	 * 查询
    	 */
    	@Test
    	public void testGet() {
    		Order order = new Order();
    		order.setOrder_id(3);
    		order.setInitOrderItem(1); //是否强制加载
    		Order o = orderDao.get(order);
    		System.out.println(o.getOrder_id());
    		System.out.println(o.getOrder_no());
    		System.out.println(o.getOrderItem());
    	}
    	
    	/**
    	 * 查询所有
    	 */
    	@Test
    	public void OrderList() {
    		Order order = new Order();
    		order.setInitOrderItem(1); //是否强制加载
    		List<Order> orderList = orderDao.OrderList(order);
    		System.out.println("订单："+orderList+"\r");
    		for (Order o : orderList) {
    			System.out.println("订单项："+o.getOrderItem());
    		}
    	}
    	
    	/**
    	 * 删除订单
    	 */
    	@Test
    	public void testDelete() {
    		Order order = new Order();
    		order.setOrder_id(3);
    		orderDao.delete(order);
    	}
    	
    
    }

package com.zy.three.dao;
    
    import static org.junit.Assert.*;
    
    import org.junit.Test;
    
    import com.zy.three.entity.OrderItem;
    
    public class OrderItemDaoTest {
    	
    	private OrderItemDao orderItemDao = new OrderItemDao();
    
    	@Test
    	public void addOrderItem() {
    		OrderItem orderItem = new OrderItem();
    		orderItem.setProduct_id(30);
    		orderItem.setQuantity(303);
    		orderItem.setOid(3);
    		orderItemDao.addOrderItem(orderItem);
    	}
    	
    	@Test
    	public void testGet() {
    		OrderItem orderItem = new OrderItem();
    		orderItem.setOrder_item_id(2);
    		OrderItem item = orderItemDao.get(orderItem);
    		System.out.println(item);
    	}
    
    }