三--3
edit：
<%@ page import="java.sql.*" pageEncoding="utf-8" errorPage="error.jsp"%>
<html>
<head>
<title>修改学生信息</title>
<link rel="stylesheet" type="text/css" href="css/style.css">
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
String id = request.getParameter("id");
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false", "root", "123456");
//Statement stmt = con.createStatement();
//ResultSet rs = stmt.executeQuery("select * from bookinfo where id=" + id);
PreparedStatement stmt = con.prepareStatement("select * from studentinfo where num=?");
stmt.setString(1, id);
ResultSet rs = stmt.executeQuery();
rs.next();
%>
<form action="editsave.jsp" method="post" onsubmit="return dosubmit();">
<h2>修改学生信息</h2>
<table style="50%">
<tr>
<th width="30%">学号：</th>
<td width="70%"><input name="stunum" type="text"
value="<%=rs.getInt(1)%>"></td>
</tr>
<tr>
<th>姓名：</th>
<td><input name="stuname" type="text"
value="<%=rs.getString(2)%>"></td>
</tr>
<tr>
<th>性别：</th>
<td>
<%
if(rs.getString(3).equals("男")){
out.print("<input type='radio' name='sex' value='男' checked>男");
out.print("<input type='radio' name='sex' value='女'>女");
}else{
out.print("<input type='radio' name='sex' value='男'>男");
out.print("<input type='radio' name='sex' value='女' checked>女");
}
%>
</td>
</tr>
<tr>
<th>出生日期：</th>
<td><input name="birthday" type="text"
value="<%=rs.getString(4)%>"></td>
</tr>
<tr>
<th>家庭住址：</th>
<td><input name="location" type="text"
value="<%=rs.getString(5)%>"></td>
</tr>
<tr>
<td colspan="2"><input type="hidden" name="id" value="<%=id%>">
<input type="submit" value="修改"> <input type="reset"
value="重置"></td>
</tr>
</table>
</form>
<%
rs.close();
stmt.close();
con.close();
%>
<script type="text/javascript" src="./js/dataCheck.js"></script>
</body>
</html>
editsave:
<%@ page import="java.sql.*" pageEncoding="utf-8" errorPage="error.jsp"%>
<html>
<head>
<title>修改完成</title>
<link rel="stylesheet" type="text/css" href="css/style.css">
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
String id = request.getParameter("id");
String stunum = request.getParameter("stunum");
String stuname = request.getParameter("stuname");
String sex = request.getParameter("sex");
String birthday = request.getParameter("birthday");
String location = request.getParameter("location");
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false", "root", "123456");
Statement stmt = con.createStatement();
String sql = "update studentinfo set num='" + stunum + "',name='" + stuname + "',sex='" + sex + "',birthday='" + birthday + "',location='"+location+
"' where num='" + Integer.valueOf(id)+"';";
int i = stmt.executeUpdate(sql);
if (i == 1) {
out.println("<h2>修改成功！</h2><br/>");
out.println("<a href='index.jsp'>返回首页</a>");
} else {
out.println("<h2>修改失败！</h2><br/>");
out.println("<a href='edit.jsp?id='" + stunum + ">重新添加</a>");
}
stmt.close();
con.close();
%>
</body>
</html>