Struts2学习笔记NO.1------结合Hibernate完成查询商品类别简单案例（工具IDEA）

2022-05-01 15:25:41

　　　　Struts2学习笔记一结合Hibernate完成查询商品类别简单案例（工具IDEA）

1.jar包准备

Hibernate+Struts2 jar包

struts的jar比较多,可以从Struts官方提供的demo中拿到必要的jar就行. 在apps/struts2-blank项目下

2.数据库准备

 /*

 Navicat MySQL Data Transfer

 Source Server         : GaGa

 Source Server Version : 50549

 Source Host           : localhost:3306

 Source Database       : day38hibernate

 Target Server Type    : MYSQL

 Target Server Version : 50549

 File Encoding         : 65001

 Date: 2018-01-26 21:04:36

 */

 SET FOREIGN_KEY_CHECKS=0;

 -- ----------------------------

 -- Table structure for t_category

 -- ----------------------------

 DROP TABLE IF EXISTS `t_category`;

 CREATE TABLE `t_category` (

   `cid` int(11) NOT NULL AUTO_INCREMENT,

   `cname` varchar(255) DEFAULT NULL,

   PRIMARY KEY (`cid`)

 ) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8;

 -- ----------------------------

 -- Records of t_category

 -- ----------------------------

 INSERT INTO `t_category` VALUES ('1', '水果');

 INSERT INTO `t_category` VALUES ('2', '电子产品');

 INSERT INTO `t_category` VALUES ('3', '食物');

 -- ----------------------------

 -- Table structure for t_product

 -- ----------------------------

 DROP TABLE IF EXISTS `t_product`;

 CREATE TABLE `t_product` (

   `pid` int(11) NOT NULL AUTO_INCREMENT,

   `pname` varchar(255) DEFAULT NULL,

   `price` double DEFAULT NULL,

   `cid` int(11) DEFAULT NULL,

   PRIMARY KEY (`pid`),

   KEY `FKq8yr5sflwtcj3jqp58x0oy7lx` (`cid`),

   CONSTRAINT `FKq8yr5sflwtcj3jqp58x0oy7lx` FOREIGN KEY (`cid`) REFERENCES `t_category` (`cid`)

 ) ENGINE=InnoDB AUTO_INCREMENT=121 DEFAULT CHARSET=utf8;

 -- ----------------------------

 -- Records of t_product

 -- ----------------------------

 INSERT INTO `t_product` VALUES ('1', '葡萄', '8', '1');

 INSERT INTO `t_product` VALUES ('2', '李子', '4.5', '1');

 INSERT INTO `t_product` VALUES ('3', '柚子', '16.8', '1');

 INSERT INTO `t_product` VALUES ('4', '樱桃', '14.8', '1');

 INSERT INTO `t_product` VALUES ('5', '橙子', '5.8', '1');

 INSERT INTO `t_product` VALUES ('6', '苹果', '6', '1');

 INSERT INTO `t_product` VALUES ('7', '西瓜', '2', '1');

 INSERT INTO `t_product` VALUES ('8', '梨子', '3.5', '1');

 INSERT INTO `t_product` VALUES ('9', '蓝莓', '10', '1');

 INSERT INTO `t_product` VALUES ('10', '香蕉', '2', '1');

 INSERT INTO `t_product` VALUES ('11', 'iPhone6s', '6500', '2');

 INSERT INTO `t_product` VALUES ('12', 'iPhone4s', '3000', '2');

 INSERT INTO `t_product` VALUES ('13', 'Mac', '18000', '2');

 INSERT INTO `t_product` VALUES ('14', '战神', '6600', '2');

 INSERT INTO `t_product` VALUES ('15', 'iPhone5s', '4300', '2');

 INSERT INTO `t_product` VALUES ('16', 'iPhone7', '8000', '2');

 INSERT INTO `t_product` VALUES ('17', '拯救者', '8000', '2');

 INSERT INTO `t_product` VALUES ('18', 'iPhone6', '5000', '2');

 INSERT INTO `t_product` VALUES ('19', 'iPhone5', '3600', '2');

 INSERT INTO `t_product` VALUES ('20', 'iPhone4', '2500', '2');

 INSERT INTO `t_product` VALUES ('21', '羊肉', '56', '3');

 INSERT INTO `t_product` VALUES ('22', '猪肉', '17', '3');

 INSERT INTO `t_product` VALUES ('23', '鱼', '7', '3');

 INSERT INTO `t_product` VALUES ('24', '上海青', '3.5', '3');

 INSERT INTO `t_product` VALUES ('25', '牛肉', '22', '3');

 INSERT INTO `t_product` VALUES ('26', '白菜', '4', '3');

 INSERT INTO `t_product` VALUES ('27', '辣条', '2', '3');

 INSERT INTO `t_product` VALUES ('28', '面包', '6', '3');

 INSERT INTO `t_product` VALUES ('29', '鸡肉', '8.6', '3');

 INSERT INTO `t_product` VALUES ('30', '方便面', '3.5', '3');

数据库准备

3.配置文件准备

　　1）Category映射文件配置

 <?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.gaga.bean.Category" table="t_category">

         <id name="cid" column="cid">

             <generator class="native"/>

         </id>

         <property name="cname" column="cname"/>

         <!--配置多方(Set)

             一,通过Set标签配置多方

                 1.1name属性: 一方类里面Set集合的变量名

           -->

         <set name="products" fetch="select" lazy="false">

             <!--1.2 column: 外键的列名  -->

             <key column="cid"/>

             <!--1.3  class: 对方类的全限定名  -->

             <one-to-many class="com.gaga.bean.Product"/>

         </set>

     </class>

 </hibernate-mapping>

Category映射文件配置

　　2）Product映射文件配置

 <?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.gaga.bean.Product" table="t_product">

         <id name="pid" column="pid">

             <generator class="native"/>

         </id>

         <property name="pname" column="pname"/>

         <property name="price" column="price"/>

         <!--一, 配置一方

              name属性: 多方类里面一方对象的属性名

              class属性: 一方类的全限定名

              column属性: 外键的列名

          -->

         <many-to-one name="category" class="com.gaga.bean.Category" column="cid" />

     </class>

 </hibernate-mapping>

Product映射文件配置

4.配置核心文件hebernate.cfg.xml

 <?xml version="1.0" encoding="UTF-8"?>

 <!DOCTYPE hibernate-configuration PUBLIC

     "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

     "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

 <hibernate-configuration>

     <session-factory>

         <!--一, 必配(驱动, 数据库的路径, 用户名, 密码 , 方言)  -->

         <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>

         <property name="hibernate.connection.url">jdbc:mysql:///day38hibernate</property>

         <property name="hibernate.connection.username">root</property>

         <property name="hibernate.connection.password">123</property>

         <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

          <!--二, 选配  -->

          <!--2.1 显示sql语句  -->

          <property name="hibernate.show_sql">true</property>

          <!--2.2 格式化sql  -->

          <property name="hibernate.format_sql">true</property>

          <!--2.3 配置hibernate自动创建表  -->

          <property name="hibernate.hbm2ddl.auto">update</property>

          <!--2.4 集成c3p0  -->

          <property name="hibernate.connection.provider_class">org.hibernate.c3p0.internal.C3P0ConnectionProvider</property>

          <property name="hibernate.c3p0.max_size">10</property>

           <!--2.6 打开session和本地线程绑定  -->

         <property name="hibernate.current_session_context_class">thread</property> 

          <!--三, 导入映射文件 resource映射文件的路径  resource属性就是映射文件的路径  -->

          <mapping resource="com/gaga/bean/Category.hbm.xml"/>

          <mapping resource="com/gaga/bean/Product.hbm.xml"/>

     </session-factory>

 </hibernate-configuration>

核心配置文件

5.Struts2.xml配置

 <?xml version="1.0" encoding="UTF-8"?>

 <!DOCTYPE struts PUBLIC

         "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"

         "http://struts.apache.org/dtds/struts-2.3.dtd">

 <struts>

     <package name="category" extends="struts-default" namespace="/">

         <action name="category_*" class="com.gaga.servlet.CategoryAction" method="{1}">

             <result name="success">list.jsp</result>

             <result name="error">msg.jsp</result>

         </action>

     </package>

 </struts>

Struts2.xml

6.utils导入

package com.gaga.utils;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

/**

 *作用:

 *1. 提供session

 *2. 保证SessionFactory全局只有一个

 *

 */

public class HibernateUtils {

    private static  Configuration configuration = null;

    private static  SessionFactory sessionFactory = null;

    /**

     * 保证SessionFactory全局只有一个

     */

    static{

         //1. 创建配置对象, 进行配置

         configuration = new Configuration();

         configuration.configure();

         //2. 构建session工厂(相当于连接池)  内置连接池 ---> c3p0 dbcp 阿里druid  光连接池

         sessionFactory = configuration.buildSessionFactory();

    }

    private HibernateUtils() {

    }

    //每次都是获得的新的session,数据库操作完成之后需要close

    public static Session openSession(){

         //3. 获得session (相当于连接)

         Session session = sessionFactory.openSession();

        return session;

    }

     //4. 从本地线程获得Session(前提是你已经在核心配置文件里面配置了 <property name="hibernate.current_session_context_class">thread</property>)

    //从本地线程获得的session(第一次没有, 获得新的存到本地线程里面,下一次直接从本地线程获得 ), 不需要close

    public static Session getCurrentSession(){

        Session session = sessionFactory.getCurrentSession();

        return session;

    }

}

7.编写Action类

package com.gaga.servlet;

import com.gaga.bean.Category;

import com.gaga.service.CategoryService;

import org.apache.struts2.ServletActionContext;

import javax.servlet.http.HttpServletRequest;

import java.util.List;

public class CategoryAction {

    public String findAll() {

        //1. 获得请求参数

        //2. 调用业务

        try {

             System.out.println("CategoryAction接受了请求");

            CategoryService categoryService = new CategoryService();

            List<Category> list = categoryService.findAll();

            //3. 把list存到域里面, 转发页面

            ServletActionContext.getRequest();

            HttpServletRequest request = ServletActionContext.getRequest();

            request.setAttribute("list", list);

            return "success";

        } catch (Exception e) {

            e.printStackTrace();

            HttpServletRequest request = ServletActionContext.getRequest();

            request.setAttribute("msg", "错误");

            return "error";

        }

    }

}

8.编写service层

 package com.gaga.service;

 import com.gaga.bean.Category;

 import com.gaga.dao.CategoryDao;

 import java.util.List;

 public class CategoryService {

     public List<Category> findAll() {

         CategoryDao categoryDao = new CategoryDao();

         return categoryDao.findAll();

     }

 }

9.编写dao层

 package com.gaga.dao;

 import com.gaga.bean.Category;

 import com.gaga.utils.HibernateUtils;

 import org.hibernate.Session;

 import org.hibernate.Transaction;

 import java.util.List;

 public class CategoryDao {

     public List<Category> findAll() {

         Session session = HibernateUtils.getCurrentSession();

         Transaction transaction = session.beginTransaction();

         List<Category> list = null;

         list = session.createCriteria(Category.class).list();

         transaction.commit();

         System.out.println("CategoryDao结果list:---"+list);

         return list;

     }

 }

10.前端jsp页面布置

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<!-- saved from url=(0044)http://localhost:8080/day41C_Product/product -->

<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

<style>#BAIDU_DSPUI_FLOWBAR,.adsbygoogle,.ad,div[class^="ad-widsget"],div[id^="div-gpt-ad-"],a[href*="cpro.baidu.com"],a[href*="@"][href*=".exe"],a[href*="/?/"][href*=".exe"],.adpushwin{display:none!important;max-width:0!important;max-height:0!important;overflow:hidden!important;}</style></head>

<body>

	<center>

		<h1>类别信息</h1>

		<table border="1px" width="500px" cellspacing="0">

				<tbody>

			<c:forEach items="${list }" var="c">

				<tr>

					<td colspan="3" style="color: red; font-size: 30px">分类名称:${c.cname }</td >

				</tr>

				<tr>

					<td>商品ID</td>

					<td>商品名称</td>

					<td>商品价格</td>

				</tr>

				 <c:forEach items="${c.products}" var="p">

					<tr>

						<td>${p.pid }</td>

						<td>${p.pname }</td>

						<td>${p.price }</td>

					</tr>

				</c:forEach>

			</c:forEach>

		</tbody></table>

	</center>

</body></html>

11.发布到Tomcat，结果显示

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