查询用户功能实现

QuerryAllServlet

package Servlet;

import Bean.User;
import Dao.UserDao;

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.util.List;

@WebServlet("/QueryAllServlet")
public class QueryAllServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
        PrintWriter out=response.getWriter();
//        -----分割线-----
        List<User> list=new UserDao().getall();
        request.setAttribute("list",list);
        request.getRequestDispatcher("/queryall.jsp").forward(request,response);
    }

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

queryall.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Administrator
  Date: 2021/4/22
  Time: 10:35
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<script language="JavaScript">
    function  p_del() {
        var msg = "您真的确定要删除吗？\n\n请确认！";
        if(confirm(msg)==true){
            return true;
        }else {
            return false;
        }
    }
</script>
<body>
<form action="/QueryAllServlet" method="post">
    <input type="submit" value="查询所有数据"/>
</form>
<table border="1" width="600px" align="center">
    <tr>
        <td>用户名</td>
        <td>邮箱</td>
        <td>生日</td>
    </tr>
    <c:forEach items="${list}" var="user">
        <tr>
            <td>${user.username}</td>
            <td>${user.email}</td>
            <td>${user.birthday}</td>
            <td><a href="/DeleteServlet?uid=${user.id}" onclick="javascript:return p_del()">删除</a>
                 <a href="/UpdateQueryServlet?uid=${user.id}">修改</a>
            </td>
        </tr>
    </c:forEach>
</table>
<%--测试项目：按ID去查询前三个--%>
<%--<form action="/QueryAllServlet" method="post">--%>
    <%--<input type="submit" value="查询前三数据"/>--%>
<%--</form>--%>
<%--<table border="1" width="600px" align="center">--%>
    <%--<tr>--%>
        <%--<td>用户名</td>--%>
        <%--<td>邮箱</td>--%>
        <%--<td>生日</td>--%>
    <%--</tr>--%>
        <%--<c:if test="${list.id>3}" var="pd">--%>
            <%--<tr>--%>
                <%--<td>${pd.username}</td>--%>
                <%--<td>${pd.email}</td>--%>
                <%--<td>${pd.birthday}</td>--%>
            <%--</tr>--%>
        <%--</c:if>--%>

</table>
</body>
</html>