2020/11/5

一.在这里写一个遍历数据库数据的过程

public List<student> bianli () {
		String sql="select * from text3";
		Connection conn = DBUtil.getConn();
		Statement state = null;
		
		ResultSet rs = null;
		List<student> list = new ArrayList<>();
		try {
			state = conn.createStatement();
			rs = state.executeQuery(sql);
			student bean = null;
			while (rs.next()) {
				String sid = rs.getString("sid");
                String sname = rs.getString("sname");
                String ssex = rs.getString("ssex");
                String sclass=rs.getString("sclass");
                String szy = rs.getString("szy");
	            
	            bean=new student(sid,sname,ssex,sclass,szy);
				list.add(bean);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			DBUtil.close(state, conn);
		}
		return list;
	}

这是dao层

  private void login(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
    	req.setCharacterEncoding("utf-8");
    	String sid = req.getParameter("sid");
		String sname = req.getParameter("sname");
		HttpSession session = req.getSession();
		    
		Dao dao=new Dao();

		List<student> holds = dao.bianli();
		req.setAttribute("holds", holds);

		if(dao.judge(sid))
		{
			req.setAttribute("message", "登录成功！");
			req.getRequestDispatcher("lookall.jsp").forward(req,resp);	
		}
		else {
			req.setAttribute("message", "没有该学生！");
			req.getRequestDispatcher("denglu.jsp").forward(req,resp);
		}
    }

这里是

利用这个进行遍历，这里是servelt层，

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
	.a{
		margin-top: 20px;
	}
	.b{
		font-size: 20px;
		 160px;
		color: white;
		background-color: greenyellow;
	}
	.tb, td {
		border: 1px solid black;
		font-size: 22px;
	}
</style>
</head>
<body>
	<div align="center">
		<h1 style="color: red;">学生信息</h1>
<a href="denglu.jsp">返回主页面</a>
		<table class="tb">
			<tr>
				<td>学号</td>
				<td>姓名</td>
				<td>性别</td>
				<td>班级</td>
				<td>专业</td>
		
			</tr>
			<!-- forEach遍历出adminBeans -->
			<c:forEach items="${holds}" var="item" varStatus="status">
				<tr>
					<td>${item.sid}</td>
					<td><a>${item.sname}</a></td>
					<td>${item.ssex}</td>
					<td>${item.sclass}</td>
					<td>${item.szy}</td>
		<td><a href="Servlet?method=look&sid=${item.sid}">删除</a></td>
				</tr>
			</c:forEach>
		</table>
	</div>
</body>
</html>

从servelt到这个jsp中就可以遍历出；

二.jsp是使用的模板，自己对这里面的数据也是不太清楚

三.点击删除