web尝试---信箱

功能

写信（增加）+读信（显示所有信件）

目录结构

数据库设计

刚开始设计了主键为id，但是后来不想用id这个属性了，但是代码写完了很麻烦不想改了。

感觉我这个id属性设置的简直多余！！！！

id重复了没法添加，但是用户怎么知道写的id是否重复呢，他也不应该看数据库挑一个没用过的id啊。

后端代码

dao层

里面有两个方法：增加+查询所有

package com.xx.note.dao;import com.xx.note.pojo.Note;
import com.xx.note.utils.JdbcBase;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class NoteDao {
    public void addNote(Note note) {
        try {
            Connection c = JdbcBase.getConnection();
            String sql = "INSERT INTO note (id, name, content, date) VALUES (?, ?, ?, ?)";
            PreparedStatement ps = c.prepareStatement(sql);
            ps.setInt(1, note.getId());
            ps.setString(2, note.getName());
            ps.setString(3, note.getContent());
            ps.setDate(4, note.getDate());

            ps.executeUpdate();

            ps.close();
            c.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public List<Note> getAllNotes() {
        List<Note> noteList = new ArrayList<>();
        try {
            Connection c = JdbcBase.getConnection();
            String sql = "SELECT * FROM note";
            PreparedStatement ps = c.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();

            while (rs.next()) {
                Note note = new Note();
                note.setId(rs.getInt("id"));
                note.setName(rs.getString("name"));
                note.setContent(rs.getString("content"));
                note.setDate(rs.getDate("date"));

                noteList.add(note);
            }

            rs.close();
            ps.close();
            c.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return noteList;
    }
}

pojo实体

4个属性，对应get，set等等方法，全参构造，空参构造...

package com.xx.note.pojo;

import java.sql.Date;

public class Note {
    private int id;
    private String name;
    private String content;
    private Date date;

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public Note(int id, String name, String content, Date date) {
        this.id = id;
        this.name = name;
        this.content = content;
        this.date = date;
    }

    public Note() {
    }

    @Override
    public String toString() {
        return "Note{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", content='" + content + '\'' +
                ", date=" + date +
                '}';
    }
}

service层

调用dao层的方法

package com.xx.note.service;

import com.xx.note.dao.NoteDao;
import com.xx.note.pojo.Note;

import java.util.List;

public class NoteService {
    private NoteDao noteDao = new NoteDao();

    public void addNote(Note note) {
        noteDao.addNote(note);
    }

    public List<Note> getAllNotes() {
        return noteDao.getAllNotes();
    }
}

servlet

有读信和写信两个功能，写了两个servlet。

NoteReadServlet

package com.xx.note.servlet;
import com.alibaba.fastjson.JSON;
import com.xx.note.pojo.Note;
import com.xx.note.service.NoteService;

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.List;

@WebServlet("/read")

public class NoteReadServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取笔记列表
        List<Note> notes = new NoteService().getAllNotes(); // 获取笔记的逻辑

        request.setAttribute("notes",notes);
        request.getRequestDispatcher("/read.jsp").forward(request,response);

        //json好使嘿嘿嘿
//        //将对象转换为json字符串
//        String json = JSON.toJSONString(notes);
//        //设置编码格式
//        response.setCharacterEncoding("utf-8");
//        response.getWriter().print(json);
    }
}

 NoteWriteServlet

提交后，提示成功，以html格式打印到网页

package com.xx.note.servlet;
import com.xx.note.pojo.Note;
import com.xx.note.service.NoteService;

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.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;

@WebServlet("/write")
public class NoteWriteServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        // 获取表单数据
        int id = Integer.parseInt(request.getParameter("id"));
        String name = request.getParameter("name");
        String content = request.getParameter("content");
        String dateStr = request.getParameter("date");

        System.out.println("测试一下嘿嘿嘿");

        // 将字符串日期转换为 Date 对象
        Date date = null;
        try {
            date = new SimpleDateFormat("yyyy-MM-dd").parse(dateStr);
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 这里可以将 Note 对象存入数据库或进行其他处理
        Note note = new Note();
        note.setId(id);
        note.setName(name);
        note.setContent(content);
//        note.setDate((java.sql.Date) date);
        note.setDate(new java.sql.Date(date.getTime()));

        NoteService noteService = new NoteService();
        //调用Service层增加方法（add），增加记录
        noteService.addNote(note);

        // 响应提交结果
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        out.println("<html><body>");
        out.println("<h1>提交成功啦!!!</h1>");
        out.println("<p>ID: " + note.getId() + "</p>");
        out.println("<p>Name: " + note.getName() + "</p>");
        out.println("<p>Content: " + note.getContent() + "</p>");
        out.println("<p>Date: " + new SimpleDateFormat("yyyy-MM-dd").format(note.getDate()) + "</p>");
        out.println("</body></html>");
    }
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);//Get请求和Post请求的处理是一样的，所以把request、response转交给Post方法就好
    }
}

utils工具类

放数据库驱动的几行代码

package com.xx.note.utils;

import com.xx.note.pojo.Note;
import com.xx.note.service.NoteService;

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.List;

public class JdbcBase {
    public static String DBDRIVER = "com.mysql.jdbc.Driver";
    public static String DBURL = "jdbc:mysql://localhost:3306/note?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai&autoReconnect=true&failOverReadOnly=false&allowPublicKeyRetrieval=true";
    public static String DBUSER = "root";
    public static String PASSWORD = "123456";
    public static Connection getConnection() throws Exception {
        Class.forName(DBDRIVER);
        return DriverManager.getConnection(DBURL, DBUSER, PASSWORD);
    }
    public static void main(String[] args) {
        try {
            Connection conn = JdbcBase.getConnection();
            System.out.println("数据库连接成功！！！");
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("数据库连接失败！！！");
        }
//        测试方法1好用
//        System.out.println(new NoteService().getAllNotes());
//        测试方法2是否好用
//        new NoteService().addNote(new Note());

    }
}

前端代码

用的jsp

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 86158
  Date: 2024/7/10
  Time: 10:09
  To change this template use File | Settings | File Templates.
--%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
    <title>来自星星的信箱📫</title>
<%--    <link rel="stylesheet" type="text/css" href="css/index.css"/>--%>
    <style>
        a{
            text-decoration: none;
        }
        a:hover{
            text-decoration: none;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Poppins', sans-serif;
        }
        .container {
            background: #ffbdc9;
            width: 100%;
            height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        nav {
            background: #fff;
            border-radius: 50px;
            padding: 10px;
            box-shadow: 0 25px 20px -20px rgba(0, 0, 0, 0.4);
        }
        nav ul li {
            list-style: none;
            display: inline-block;
            padding: 13px 35px;
            margin: 10px;
            font-size: 18px;
            font-weight: 500;
            color: #777;
            cursor: pointer;
            position: relative;
            z-index: 2;
            transition: color 0.5s;
        }
        nav ul li::after {
            content: '';
            background: #f44566;
            width: 100%;
            height: 100%;
            border-radius: 30px;
            position: absolute;
            top: 100%;
            left: 50%;
            transform: translate(-50%, -50%);
            z-index: -1;
            opacity: 0;
            transition: top 0.5s,opacity 0.5s;
        }
        nav ul li:hover{
            color: #fff;
        }
        nav ul li:hover::after{
            top: 50%;
            opacity: 1;
        }
    </style>

</head>

<body>
<%--<div class="bg">--%>
<div class="container">
    <nav>
        <ul>
            <li><a href="read">读信</a></li>
            <li><a href="loveheart.jsp">💗</a></li>
            <li><a href="write.jsp">写信</a></li>
        </ul>
    </nav>
</div>
<%--</div>--%>

</body>

</html>

read.jsp 

<%--
  Created by IntelliJ IDEA.
  User: 86158
  Date: 2024/7/12
  Time: 12:57
  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" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>

<%@ page import="java.util.List" %>
<%@ page import="com.xx.note.pojo.Note" %>
<html>
<head>
    <title>read</title>
    <style>
        table {
            border-collapse: collapse;
            margin: auto
        }
        table, td, th {
            border: 1px solid black;
        }
    </style>
</head>
<body>
<table>
    <tr>
        <th>寄信人</th>
        <th>内容</th>
        <th>日期</th>
    </tr>
    <c:forEach items="${notes}" var="note">
        <tr>
            <td>${note.name}</td>
            <td>${note.content}</td>
            <td>${note.date}</td>
        </tr>
    </c:forEach>
</table>

</body>
</html>

write.jsp 

注意form表单的action路径写完整。

<%--
  Created by IntelliJ IDEA.
  User: 86158
  Date: 2024/7/12
  Time: 12:57
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>write</title>
</head>
<body>
<form method="post" action="/node/write">
    <label for="id">ID:</label>
    <input type="number" id="id" name="id" required><br><br>

    <label for="name">Name:</label>
    <input type="text" id="name" name="name" required><br><br>

    <label for="content">Content:</label><br>
    <textarea id="content" name="content" rows="4" cols="50" required></textarea><br><br>

    <label for="date">Date:</label>
    <input type="date" id="date" name="date" required><br><br>

    <input type="submit" value="提交信息">
</form>
</body>
</html>

loveheart.jsp

爱写啥写啥

效果展示