友佳书屋实训项目（一）

杨校

发布于 2021-10-13 16:10:40

7770

文章被收录于专栏：Java技术分享圈Java技术分享圈

友佳书屋

1.功能演示

一、类目

分析实体

类目，单词为 Category 实体的名称就定义下来了 |— 属性： categoryId（用于确定的唯一性）；类目名称 categoryName；类目描述 categoryDescription

1.1 实体类:

   1, 定义属性变量
   2，使用快捷键Alt+Insert 生成getter和setter方法
   3， 使用快捷键Alt+Insert 生成toString方法，便于打印查看具体数据
   4，使用快捷键Alt+Insert  生成构造方法
    4.1， 有参数的构造方法
    4.2， 无参数的构造方法

public class Category {

   private int categoryId;
   private String categoryName;
   private String categoryDescription;
   
   //  有参数构造方法  要id
   public Category(int categoryId, String categoryName, String categoryDescription) {
       this.categoryId = categoryId;
       this.categoryName = categoryName;
       this.categoryDescription = categoryDescription;
   }
//  有参数构造方法  不要id
   public Category(String categoryName, String categoryDescription) {
       this.categoryName = categoryName;
       this.categoryDescription = categoryDescription;
   }
//  无参数的构造方法: Alt+Insert  再去选择 Override Methods  默认Object()方法  直接回车
   public Category() {
       super();
   }

   @Override
   public String toString() {
       return "Category{" +
               "categoryId=" + categoryId +
               ", categoryName='" + categoryName + '\'' +
               ", categoryDescription='" + categoryDescription + '\'' +
               '}';
   }

   public int getCategoryId() {
       return categoryId;
   }

   public void setCategoryId(int categoryId) {
       this.categoryId = categoryId;
   }

   public String getCategoryName() {
       return categoryName;
   }

   public void setCategoryName(String categoryName) {
       this.categoryName = categoryName;
   }

   public String getCategoryDescription() {
       return categoryDescription;
   }

   public void setCategoryDescription(String categoryDescription) {
       this.categoryDescription = categoryDescription;
   }
}

1.2 编写Service层

Service层有接口和实现类

（1）先去编写接口，接口的命名规范为 [实体类的名称+ Service],本接口为CategoryService，实现类为CategoryServiceImpl （2）考虑该接口内哪些功能，功能对应的是方法。功能如下: 增加类目删除类目修改类目查询所有类目根据类目编号categoryId查询类目对应的是五个方法：增加类目方法，参数列表是:Category category; 返回值类型为int 删除类目方法，参数列表是:int categoryId; 返回值类型为int 修改类目方法，参数列表是:Category category; 返回值类型为int 查询所有类目方法，无参数返回值类型为List<Category>; 【因为查询的所有类目，不再是单一的一个类目，需要有容器存储所有类目对象，该容器合适的是集合，便于查询的是ArrayList集合。{ArrayList特性是查询快、增删慢 | LinkedList特性是查询慢、增删快}】根据类目编号查询方法，参数列表是:int categoryId; 返回值类型为Category; 【因为查询的是一个类目，所有就是对象存储。】

代码如下:

package cn.javabs.service;

import cn.javabs.entity.Category;
import java.util.List;

public interface CategoryService {
    
    int addCategory(Category category);

    int delCategory(int categoryId);

    int editCategory(Category category);

    List<Category> findAllCategory();

    Category findCategoryById(int   categoryId);

}

接口的实现类: 无需代码编写，可利用idea软件进行代码生成，步骤如下: (1) 放在接口名称后，按快捷键 Alt+Enter

选中 Implement Interface 回车，需要补充包名.impl再去点击OK

继续选择OK 效果如图:

1.3 编写Dao层

Dao层有接口和实现类

（1）先去编写接口，接口的命名规范为 [实体类的名称+ Dao],本接口为CategoryDao，实现类为CategoryDaoImpl （2）考虑该接口内哪些功能，功能对应的是方法。功能如下: 增加类目删除类目修改类目查询所有类目根据类目编号categoryId查询类目对应的是五个方法：增加类目方法，参数列表是:Category category; 返回值类型为int 删除类目方法，参数列表是:int categoryId; 返回值类型为int 修改类目方法，参数列表是:Category category; 返回值类型为int 查询所有类目方法，无参数返回值类型为List<Category>; 【因为查询的所有类目，不再是单一的一个类目，需要有容器存储所有类目对象，该容器合适的是集合，便于查询的是ArrayList集合。{ArrayList特性是查询快、增删慢 | LinkedList特性是查询慢、增删快}】根据类目编号查询方法，参数列表是:int categoryId; 返回值类型为Category; 【因为查询的是一个类目，所有就是对象存储。】

在CategoryServiceImpl实现类内编写实例化操作，步骤如下：（1）在类内编写实例化{也就是new} CategoryDao categoryDao = new CategoryDaoImpl(); 对象名称是categoryDao 写完会发现，CategoryDao 、CategoryDaoImpl 呈后红色状态，暂不需要处理，可继续编写。（2）利用对象去完成增删改查操作添加类目方法：return categoryDao.add(Category) ; 删除类目方法：return categoryDao.del(CategoryId) ; 修改类目方法：return categoryDao.edit(Category) ; 获取所有类目方法：return categoryDao.getAllCategory() ; 根据编号查询类目方法：return categoryDao.getCategoryById(CategoryId) ; 写完以上方法，仍会呈现红色的状态

（3）解决报错问题 ①将光标放在CategoryDao后，按快捷键 Alt+Enter,选择 Create Interface CategoryDao

修改包名为dao，然后Ok回车

	② 将光标放在add后，按快捷键 Alt+Enter,选择 Create method  add in CategoryDao 	然后回车

③ 将光标放在del后，按快捷键 Alt+Enter,选择 Create method del in CategoryDao 然后回车 ④ 将光标放在edit后，按快捷键 Alt+Enter,选择 Create method edit in CategoryDao 然后回车 ⑤ 将光标放在getAllCategory后，按快捷键 Alt+Enter,选择 Create method getAllCategory in CategoryDao 然后回车 ⑥ 将光标放在getCategoryById后，按快捷键 Alt+Enter,选择 Create method getCategoryById in CategoryDao 然后回车 ⑦ 将光标放在CategoryDaoImpl实现类后，按快捷键 Alt+Enter,选择 Create class CategoryDaoImpl

修改包名为dao.impl，然后OK

（4）回到CategoryDaoImpl实现类内，会发现报错：

解决办法: 将光标放在CategoryDao后，按快捷键 Alt+Enter,选择 implment methods 然后回车、再回车。

截至到目前，需进一步编写CategoryDaoImpl实现类内的功能代码，却发现缺少数据源连接池，接下来进行创建数据库连接池，这里采用的是阿里巴巴数据源Druid,具体内容点此查看。

1.4 创建工具类

下载jar包

package cn.javabs.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class DruidUtil {
    public static DataSource dataSource;

    static {

        try {
            InputStream is = DruidUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");

            Properties pro = new Properties();

            pro.load(is);

            dataSource = DruidDataSourceFactory.createDataSource(pro);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

    }
    
    public static DataSource getDataSource(){
        return dataSource;
    }

    
    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }

}

在src下创建配置文件:jdbc.proeprties

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/bookmarket
username=root
password=sorry

1.5 完善CategoryDaoImpl

package cn.javabs.dao.impl;

import cn.javabs.dao.CategoryDao;
import cn.javabs.entity.Category;
import cn.javabs.util.DruidUtil;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import java.sql.SQLException;
import java.util.List;

public class CategoryDaoImpl implements CategoryDao {

    QueryRunner qr = new QueryRunner(DruidUtil.getDataSource());

    @Override
    public int add(Category category) {
        try {
            return qr.update("insert into category(categoryName,categoryDescription) values(?,?)",
                       category.getCategoryName(),category.getCategoryDescription());
        } catch (SQLException e) {
            throw new RuntimeException(e);//  转成运行时异常抛出
        }
    }

    @Override
    public int del(int categoryId) {
        try {
            return qr.update("delete from  category where categoryId = ?",categoryId);
        } catch (SQLException e) {
            throw new RuntimeException(e);//  转成运行时异常抛出
        }
    }

    @Override
    public int edit(Category category) {
        try {
            return qr.update("update category set categoryName = ?,categoryDescription = ? where categoryId = ?",
                    category.getCategoryName(),category.getCategoryDescription(),category.getCategoryId());
        } catch (SQLException e) {
            throw new RuntimeException(e);//  转成运行时异常抛出
        }
    }

    @Override
    public List<Category> getAllCategory() {
        try {
            return qr.query("select * from category",new BeanListHandler<Category>(Category.class));
        } catch (SQLException e) {
            throw new RuntimeException(e);//  转成运行时异常抛出
        }
    }

    @Override
    public Category getCategoryById(int categoryId) {
        try {
            return qr.query("select * from category where  categoryId = ?",new BeanHandler<Category>(Category.class),categoryId);
        } catch (SQLException e) {
            throw new RuntimeException(e);//  转成运行时异常抛出
        }
    }
}

1.6 编写 CategoryServlet

package cn.javabs.web.servlet;

import cn.javabs.entity.Category;
import cn.javabs.service.CategoryService;
import cn.javabs.service.impl.CategoryServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.invoke.VolatileCallSite;
import java.util.List;

@WebServlet("/categoryServlet")
public class CategoryServlet extends HttpServlet {

    CategoryService cs = new CategoryServiceImpl();

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

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //  解决乱码
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");

        // 接受参数、用于判断是找哪个方法
        String op = request.getParameter("op");

        switch (op){
            case "addCategory":
                addCategory(request, response);
                break;
            case "delCategory":
                delCategory(request, response);
                break;
            case "editCategory":
                editCategory(request, response);
                break;
            case "categoryList":
                categoryList(request, response);
                break;
            case "updateCategory":
                updateCategory (request, response);
                break;

            default:
                System.out.println("没有找到对应的参数！请查证");
        }
    }
    //    修改之数据回显
    private void updateCategory(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String id = request.getParameter("id");
        String categoryName = request.getParameter("categoryName");
        String categoryDescription = request.getParameter("categoryDescription");
        int categoryId = Integer.parseInt(id);

        Category category = new Category(categoryId, categoryName, categoryDescription);
        int row = cs.editCategory(category);
        if (row>0){
            request.setAttribute("msg","修改类目成功！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }else{
            request.setAttribute("msg","修改类目失败！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }
    }

    private void categoryList(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Category> list = cs.findAllCategory();
        if (list.size() > 0&& list != null) {
            request.setAttribute("list", list);
            request.getRequestDispatcher("categoryList.jsp").forward(request,response);
        }else{
            request.setAttribute("msg","尚未查询到相关类目！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }

    }

//    数据回显
    private void editCategory(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String id = request.getParameter("id");
        int categoryId = Integer.parseInt(id);
        Category category = cs.findCategoryById(categoryId);
        if (category != null){
            request.setAttribute("category", category);
            request.getRequestDispatcher("editCategory.jsp").forward(request,response);
        }else{
            request.setAttribute("msg","修改类目失败，请查证！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }
    }

    private void delCategory(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String id = request.getParameter("id");
        int categoryId = Integer.parseInt(id);
        int row = cs.delCategory(categoryId);
        if (row>0){
            request.setAttribute("msg","删除类目成功！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }else{
            request.setAttribute("msg","删除类目失败！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }
    }

    /**
     * 添加类目
      * @param request
     * @param response
     */
    private void addCategory(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String categoryName = request.getParameter("categoryName");
        String categoryDescription = request.getParameter("categoryDescription");

        Category category = new Category(categoryName, categoryDescription);

        int row = cs.addCategory(category);

        if (row>0){
            request.setAttribute("msg","添加类目成功！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }else{
            request.setAttribute("msg","添加类目失败！");
            request.getRequestDispatcher("message.jsp").forward(request,response);
        }
    }
}

1.7页面布局级设计

1.7.1添加页面

<%--
  Created by IntelliJ IDEA.
  User: Mryang
  Date: 2021/10/11
  Time: 14:18
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>添加图书类目</title>
</head>
<body>
						<form action="/categoryServlet?op=addCategory" method="post">
						    类目名称：<input type="text" name="categoryName" id="categoryName"> <br/>
						    类目描述：<input type="text" name="categoryDescription" id="categoryDescription">  <br/>
						    <input type="submit" value="添加类目">
						</form>
</body>
</html>

1.7.2查询页面

<%--
  Created by IntelliJ IDEA.
  User: Mryang
  Date: 2021/10/11
  Time: 14:22
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!--不要遗忘这条指令-->
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
					<table>
					    <tr>
					        <td>编号</td>
					        <td>名称</td>
					        <td>描述</td>
					        <td>操作</td>
					    </tr>
					
					
					    <c:forEach items="${list}" var="item">
					        <tr>
					            <td>${item.categoryId}</td>
					            <td>${item.categoryName}</td>
					            <td>${item.categoryDescription}</td>
					            <td>
					                <a href="/categoryServlet?op=editCategory&id=${item.categoryId}">修改</a>
					                <a href="JavaScript:deleteCategory('${item.categoryId}')">删除</a>
					            </td>
					        </tr>
					    </c:forEach>
					
					</table>
</body>
</html>
				<script>
				    function deleteCategory(id) {
				      var sure =   confirm("您确定要删除此项吗？")
				        if (sure){
				            kk = "/categoryServlet?op=delCategory&id="  + id;
				        }
				    }
				</script>

1.7.3修改页面

<%--
  Created by IntelliJ IDEA.
  User: Mryang
  Date: 2021/10/11
  Time: 14:18
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改图书类目</title>
</head>
<body>
					<form action="/categoryServlet?op=updateCategory&id=${category.categoryId}" method="post">
					    类目名称：<input type="text" value="${category.categoryName}" name="categoryName" id="categoryName"> <br/>
					    类目描述：<input type="text" value="${category.categoryDescription}" name="categoryDescription" id="categoryDescription">  <br/>
					    <input type="submit" value="修改类目">
					</form>
</body>
</html>

1.8 编写MySQL数据库的代码

-- 创建数据库
create  database bookmarket;

-- 选中数据库
use bookmarket;

--  创建  类目 数据表
CREATE  table  category(

   categoryId int primary key auto_increment, --  auto_increment  自动递增
   categoryName varchar(50),
   categoryDescription varchar(250)

);

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原始发表：2021/10/11 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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