hibernate映射一对多，单向关系，初学例子二

最新推荐文章于 2021-04-11 12:47:59 发布

原创最新推荐文章于 2021-04-11 12:47:59 发布 · 767 阅读

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#hibernate #string #class #generator #image #bean

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本文介绍了一个使用Hibernate框架实现的订单与客户实体关联映射案例，包括实体类定义、映射文件配置及简单的测试代码。演示了如何进行一对多关系的数据持久化操作，并通过级联保存简化开发流程。

1。order bean

package bean;

import java.io.Serializable;

/**
*
* @author zwc
*
*/

@SuppressWarnings("serial")
public class Order implements Serializable{
private long id;
private String orderNumber;
private Customer customer;

public long getId() {
  return id;
}
protected void setId(long id) {
  this.id = id;
}
public String getOrderNumber() {
  return orderNumber;
}
public void setOrderNumber(String orderNumber) {
  this.orderNumber = orderNumber;
}
public Customer getCustomer() {
  return customer;
}
public void setCustomer(Customer customer) {
  this.customer = customer;
}
}

2。order.hbm.xml

3.customer bean

package bean;

import java.io.Serializable;
import java.sql.Timestamp;

/**
*
* @author zwc
*
*/

@SuppressWarnings("serial")
public class Customer implements Serializable{
private Long id;
private String firstName = "N";
private String lastName = "N";
private int phone;
private boolean married;
private char sex;
private byte[]image;
private Timestamp registeredTime;
private int count;

public Customer(){
  //empty
}

public Long getId() {
  return id;
}
public void setId(Long id) {
  this.id = id;
}
public String getFirstName() {
  return firstName;
}

public void setFirstName(String firstName) {
this.firstName = firstName;
}

public String getLastName() {
return lastName;
}

public void setLastName(String lastName) {
this.lastName = lastName;
}

protected String getName() {
  return firstName + "-" + lastName;
}
protected void setName(String name) {
  String [] names = name.split("-");
  if(names.length >= 1){
   this.firstName = names[0];
  }
  if(names.length >= 2){
   this.lastName = names[1];
  }
}
public int getPhone() {
  return phone;
}
public void setPhone(int phone) {
  this.phone = phone;
}
public boolean isMarried() {
  return married;
}
public void setMarried(boolean married) {
  this.married = married;
}
public char getSex() {
  return sex;
}
public void setSex(char sex) {
  this.sex = sex;
}
public byte[] getImage() {
  return image;
}
public void setImage(byte[] image) {
  this.image = image;
}
public Timestamp getRegisteredTime() {
  return registeredTime;
}
public void setRegisteredTime(Timestamp registeredTime) {
  this.registeredTime = registeredTime;
}

public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}

}

4.customer.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="bean">
<class name="bean.Customer" table="t_customer">
  <id name="id" column="id" type="long">
   <generator class="native"/>
  </id>
  <property name="name" column="name" type="string" not-null="true"/>
  <property name="phone" column="phone" type="integer"/>
  <property name="married" column="married" type="boolean"/>
  <property name="sex" column="sex" type="character"/>
  <property name="image" column="image" type="binary"/>
  <property name="registeredTime" column="registered_time" type="timestamp"/>

  <property name="count" formula="(select count(*) from t_customer as c)"/>
</class>
</hibernate-mapping>

5.测试类

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Timestamp;
import java.util.Iterator;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import bean.Customer;
import bean.Order;

/**
*
* @author zwc
*
*/
@SuppressWarnings("serial")
public class OperateOrder extends HttpServlet {
private Logger logger = Logger.getLogger(OperateOrder.class);

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request,response);
}

public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  response.setCharacterEncoding("UTF-8");
  request.setCharacterEncoding("UTF-8");
  response.setContentType("text/html;charset=UTF-8");
  PrintWriter out = response.getWriter();

  Configuration config = new Configuration();
  Session session = config.addClass(Order.class)
   .addClass(Customer.class)
   .buildSessionFactory()
   .openSession();
  Transaction t = session.beginTransaction();
  try {
   //Customer ic = (Customer) session.get(Customer.class, new Long(93));
   Customer ic = new Customer();
   ic.setFirstName("IC1");
   ic.setLastName("IC11");
   ic.setRegisteredTime(new Timestamp(System.currentTimeMillis()));
   session.save(ic);
   Order io = new Order();
   io.setOrderNumber("Insert123455789");
   io.setCustomer(ic);
   session.save(io);

注意：对于这里的保存，可以先保存“一对多”，是customer持久化，然后保存order

或者，用hibernate的级联保存 cascade="save-update" 用在order.hbm.xml 的 <many-to-one/>上

   t.commit();
  } catch (Exception e) {
   t.rollback();

注意：当保存失败，要回滚，这是一个，好的习惯！！！   logger.debug("保存Order失败");
  }
  Query query = session.createQuery("from Order");
  Iterator<Order> i = (Iterator<Order>) query.iterate();
  while(i.hasNext()){
   Order order = i.next();
   out.println(order.getCustomer().getFirstName()
     + "-" + order.getCustomer().getLastName()
     + "................" + order.getOrderNumber());
  }

}

}