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() {}@Overridepublic 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 {@Overrideprotected 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 {@Overrideprotected 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>");}@Overridepublic 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: 86158Date: 2024/7/10Time: 10:09To 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: 86158Date: 2024/7/12Time: 12:57To 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: 86158Date: 2024/7/12Time: 12:57To 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