留言板功能的實現

代碼實現

本文承接上文你品，你細品留言板功能的總結，本人新手有代碼可以優化的地方法，歡迎大家指出。

已上傳github，有需要的可以看一下

目錄展示

dao層：數據庫連接層
domain：實體類
service層：業務層
test層：測試代碼層
util層：工具層
web.servlet：主要是用來轉發頁面的

代碼邏輯

用戶登錄

login.jsp---> LoginServlet（獲取用戶的賬號及密碼進行校驗）-->
1.登錄成功，進入NewsListServlet
2.登錄失敗，進入login.jsp進行回顯

用戶註冊

regist.jsp --> RegistServlet（獲取用戶的賬號及密碼進行註冊）-->可以選擇進行登錄

留言板顯示

通過NewListServlet獲取到數據庫的list信息--> 在list.jsp中進行顯示

刪除留言

點擊刪除按鈕-->DelNewsservlet（調用service數據庫的刪除）-->NewsListServlet-->list.jsp

添加留言

點擊添加按鈕-->填充留言板內容-->AddNewsServlet-->NewsListServlet-->list.jsp

修改留言

這個相對來說就比較複雜一點了，首先要進行信息的回顯
更改按鈕--> FindNewsList-->update.jsp
修改留言 ： 確定按鈕-->UpdateNewsServlet-->NewsListServlet-->list..jsp

代碼實現

<%--
  Created by IntelliJ IDEA.
  User: 張振東
  Date: 2020/4/12
  Time: 21:19
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>留言板---登錄界面</title>

    <style>
        .td_left{
            padding-top: 50px;
            width: 100px;
            text-align: right;
            height: 45px;
        }
        .td_right{
            /*    本身就是表格，就是內邊距*/
            padding-left:50px ;
            padding-top: 50px;

        }
        #username,#password{
            width: 251px;
            height: 33px;
            border: 1px solid ;
            /*    邊框圓角*/
            border-radius: 5px;
            padding-left: 10px;
        }
        .rg_layout {
            width: 1000px;
            height: 700px;
            background: white;
            border: 8px solid #EEEEEE;
            /*div居中*/
            margin: auto;
            margin-top: 20px;

        }

        .rg_left {

            float: left;
            margin-top: 15px;
        }

        .rg_center {
            margin-left: 200px;
            margin-top: 10px;
            /*border: 1px solid #FF0000;*/
            float: left;
            width: 450px;
        }

        .rg_right {
            margin: 15px;

            float: right;
        }
        *{
            margin: 0px;
            padding: 0px;
            box-sizing: border-box;
        }
        .rg_left >p:first-child{
            color: red;
            font-size: 20px;

        }
        .rg_left >p:last-child{
            color: #A6A6A6;
            font-size: 20px;

        }
        .rg_right p{
            font-size: 15px;
        }
        .rg_right p a{
            color: pink;
        }
        #btn_submit{
            width: 150px;
            height: 50px;
            margin-top: 50px;
            border:1px solid yellow;
            background-color: yellow;

        }
    </style>
    <script>
        var error='<%=request.getParameter("error")%>';
        if(error=='yes'){
            alert("登錄失敗");
        }
    </script>
</head>
<body>
<div class="rg_layout">
    <div class="rg_left">
        <p>留言板用戶登錄</p>
        <p>USER LOGIN</p>
    </div>
    <div class="rg_center">
        <div class="rg_from">
            <form action="loginServlet" method="post">
                <table border="0">
                    <tr>
                        <td class="td_left"><label for="username">用戶名</label></td>
                        <td class="td_right"><input type="text" name="username" id="username" placeholder="請輸入賬號名稱"></td>
                    </tr>

                    <tr>
                        <td class="td_left"><label for="password">密碼</label></td>
                        <td class="td_right"><input type="password" name="password" id="password" placeholder="請輸入密碼"></td>
                    </tr>

                    <tr>
                        <td align="center" colspan="2"><input type="submit" value="登錄" id="btn_submit"></td>
                    </tr>
                </table>
            </form>
        </div>
    </div>
    <div class="rg_right">
        <p>還未註冊？<a href="regist.jsp">趕快去註冊</a></p></div>
</div>
<footer>
    <center>
        
        <font size=5px" color="#a9a9a9" face="楷體">©️1813004745張振東 </font><font color="red" size="5px"><a href="admin.jsp">管理後臺</a></font>
    </center>
</footer>
</body>
</html>

regist.jsp

<%--
  Created by IntelliJ IDEA.
  User: 張振東
  Date: 2020/4/12
  Time: 21:19
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>留言板---註冊界面</title>
    <style>
        .td_left{
            padding-top: 50px;
            width: 100px;
            text-align: right;
            height: 45px;
        }
        .td_right{
            /*    本身就是表格，就是內邊距*/
            padding-left:50px ;
            padding-top: 50px;

        }
        #username,#password{
            width: 251px;
            height: 33px;
            border: 1px solid ;
            /*    邊框圓角*/
            border-radius: 5px;
            padding-left: 10px;
        }
        .rg_layout {
            width: 1000px;
            height: 700px;
            background: white;
            border: 8px solid #EEEEEE;
            /*div居中*/
            margin: auto;
            margin-top: 20px;

        }

        .rg_left {

            float: left;
            margin-top: 15px;
        }

        .rg_center {
            margin-left: 200px;
            margin-top: 10px;
            /*border: 1px solid #FF0000;*/
            float: left;
            width: 450px;
        }

        .rg_right {
            margin: 15px;

            float: right;
        }
        *{
            margin: 0px;
            padding: 0px;
            box-sizing: border-box;
        }
        .rg_left >p:first-child{
            color: red;
            font-size: 20px;

        }
        .rg_left >p:last-child{
            color: #A6A6A6;
            font-size: 20px;

        }
        .rg_right p{
            font-size: 15px;
        }
        .rg_right p a{
            color: pink;
        }
        #btn_submit{
            width: 150px;
            height: 50px;
            margin-top: 50px;
            border:1px solid yellow;
            background-color: yellow;

        }

    </style>
    <script>
        var error1='<%=request.getParameter("error")%>';
        if(error1=='no'){
            alert("註冊成功");
        }
        if(error1=='yes'){
            alert("註冊失敗");
        }
    </script>
</head>
<body>
<div class="rg_layout">
    <div class="rg_left">
        <p>留言板用戶註冊</p>
        <p>USER REGISTER</p>
    </div>
    <div class="rg_center">
        <div class="rg_from">
            <form action="registServlet" method="post">
                <table border="0">
                    <tr>
                        <td class="td_left"><label for="username">用戶名</label></td>
                        <td class="td_right"><input type="text" name="username" id="username" placeholder="請輸入賬號"></td>
                    </tr>

                    <tr>
                        <td class="td_left"><label for="password">密碼</label></td>
                        <td class="td_right"><input type="password" name="password" id="password" placeholder="請輸入密碼"></td>
                    </tr>

                    <tr>
                        <td align="center" colspan="2"><input type="submit" value="註冊" id="btn_submit" ></td>
                    </tr>
                </table>
            </form>
        </div>
    </div>
    <div class="rg_right">
        <p>註冊成功？<a href="login.jsp">立即登錄</a></p></div>
</div>
</body>
</html>

LoginServlet

package cn.zzd.web.servlet;



import cn.zzd.dao.impl.UserDaoImpl;
import cn.zzd.domain.User;
import cn.zzd.service.UserService;
import cn.zzd.service.impl.UserServiceImpl;

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;


/**
 * @author 張振東
 * @version V1.0
 * @Title:
 * @Package
 * @Description: (用一句話描述該文件做什麼)
 * @date：
 */
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      //設置編碼
      req.setCharacterEncoding("utf-8");
      //獲取請求參數
      String username=req.getParameter("username");
      String password=req.getParameter("password");
      //封裝user對象
      User loginUser = new User();
      loginUser.setPassword(password);
      loginUser.setUsername(username);
      //獲取所有請求參數
      UserService userService = new UserServiceImpl();
      User user =userService.login(loginUser);
      if(user==null){
         //登錄失敗
         resp.sendRedirect("login.jsp?error=yes");
      }else{
         //登錄成功
         //存儲數據
         req.setAttribute("username",username);
         req.getRequestDispatcher("/newsListServlet?username="+username).forward(req,resp);
      }
   }

   @Override
   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      this.doGet(req,resp);
   }
}

RegistServlet：

package cn.zzd.web.servlet;

import cn.zzd.dao.impl.UserDaoImpl;
import cn.zzd.domain.User;
import cn.zzd.service.UserService;
import cn.zzd.service.impl.UserServiceImpl;

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;

/**
 * @author 張振東
 * @version V1.0
 * @Title:
 * @Package
 * @Description: (用一句話描述該文件做什麼)
 * @date：
 */
@WebServlet("/registServlet")
public class RegistServlet extends HttpServlet {
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//設置編碼
      request.setCharacterEncoding("utf-8");
      //獲取請求參數
      String username=request.getParameter("username");
      String password=request.getParameter("password");
      //封裝user對象
      User registUser = new User();
      registUser.setPassword(password);
      registUser.setUsername(username);
      //獲取所有請求參數
      UserService userService = new UserServiceImpl();
      int result =userService.regist(registUser);
      if(result!=0){
         response.sendRedirect("regist.jsp?error=no");
      }else{
         response.sendRedirect("regist.jsp?error=yes");
      }
   }



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

NewsListServlet：



package cn.zzd.web.servlet;

import cn.zzd.domain.News;
import cn.zzd.service.NewsService;

import cn.zzd.service.impl.NewsServiceImpl;


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;

/**
 * @author 張振東
 * @version V1.0
 * @Title:
 * @Package
 * @Description: (用一句話描述該文件做什麼)
 * @date：
 */
@WebServlet("/newsListServlet")
public class NewsListServlet extends HttpServlet {
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      NewsService service = new NewsServiceImpl();
      List<News> news = service.findall();
      request.setAttribute("news", news);
      //System.out.println(request.getParameter("username"));
      if ("1813004745".equals(request.getParameter("username"))||request.getParameter("username")==null) {
         request.getRequestDispatcher("/list2.jsp").forward(request, response);
      } else {
         request.getRequestDispatcher("/list.jsp?username=" + request.getParameter("username")).forward(request, response);

      }

   }

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

更多的代碼可以去我的github看看！！！

長路漫漫，JAVA爲伴！！！

帶你入手web入門小項目-留言板

留言板功能的實現

目錄展示

代碼邏輯

用戶登錄

用戶註冊

留言板顯示

刪除留言

添加留言

修改留言

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