javaweb的三层模型

本节的内容在没有数据的情况下实现后台和界面的联调

使用的是下面的三个包

Books.java文件

package com.huxt.model;


public class Books {
    private double id;
    private String name;
    private int bookCount;
    private String author;


    @Override
    public String toString() {
        return "BooksDao{" +
                "id=" + id +
                ", name='" + name + ''' +
                ", bookCount=" + bookCount +
                ", author='" + author + ''' +
                '}';
    }

    public double getId() {
        return id;
    }

    public void setId(double id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getBookCount() {
        return bookCount;
    }

    public void setBookCount(int bookCount) {
        this.bookCount = bookCount;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }
}

BooksDao.java

package com.huxt.Dao;

import com.huxt.model.Books;
import java.util.ArrayList;


public class BooksDao {
    public ArrayList getAllBook(){
        ArrayList booksList = new ArrayList<>();
        String bookName[] = new String[]{"大学英语","高等数学","java高级程序设计","c++程序设计"};
        String bookAthor[] =  new String[]{"张三","李四","王五","王二"};
        for (int i = 0;i
            Books books = new Books();
            books.setId(Math.floor(Math.random()*12314));
            books.setName(bookName[i]);
            books.setAuthor(bookAthor[i]);
            books.setBookCount(55);
            booksList.add(books);

        }
        // 将装有书数据的集合返回给调用者
        return booksList;
    }
}

BookServlet.java

package com.huxt.servlet;

import com.huxt.Dao.BooksDao;
import com.huxt.model.Books;

import javax.servlet.RequestDispatcher;
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.util.ArrayList;


@WebServlet("/booksListServlet")
public class BooksListServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        BooksDao booksDao = new BooksDao();
        ArrayList allBook = booksDao.getAllBook();
        req.setAttribute("allBook",allBook);

        RequestDispatcher dispatcher = req.getRequestDispatcher("showBook.jsp");
        dispatcher.forward(req,resp);
    }
}

为了方便将jsp文件写在了web目录下

<%--
  Created by IntelliJ IDEA.
  User: win
  Date: 2022/4/15
  Time: 19:39
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>


    


<%--在给界面对数据进行展示--%>

        

    
图书信息表
    

        
图书条目
        
图书id
        
书名
        
作者
        
图书数量
    
    

            
${status.count}
            
${item.id}
            
${item.name}
            
${item.author} 
            
${item.bookCount}
        
    

运行效果如图所示