我已经准备了一个用于插入、查看和删除数据的表单，现在我想添加选项来编辑该数据，但要么我按照错误的方式进行操作，要么我不知道该怎么做。
那么任何人都可以帮助我继续编辑输入的数据吗？我应该参考旧的html页面来编辑还是新页面或.. ?? 我知道我没有遵循 MVC 结构，但我想在单页中完成整个编码，所以等待帮助.. 谢谢。
这些是我的代码。
数据存储.html
<html>
<head>
<title>Data insertion form</title>
</head>
<body>
<form method= "get" action="/datainsert/DataInsertTable">
<h1><center>Enter the required information</center></h1>
<table>
<tr>
<td>Name</td>
<td> :- </td>
<td><input type="text" name="name"></input></td>
</tr>
<tr>
<td>Roll Number</td>
<td> :- </td>
<td><input type="text" name="roll"></input></td>
</tr>
<tr>
<td>Class </td>
<td> :- </td>
<td><input type="text" name="clas"></input></td>
</tr>
<tr>
<td>Mobile Number </td>
<td> :- </td>
<td><input type="text" name="mono"></input></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="Submit" width="16" onClick=alert("data stored.");></input></td>
</tr>
</table>
</form>
</body>
</html>
数据插入表.java
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class DataInsertTable extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
PrintWriter pwinsert = res.getWriter();
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
Statement st = null;
out.println("<html>");
out.println("<head>");
out.println("<title>User Data</title>");
out.println("<script language = JavaScript>");
out.println("<function f1() {>");
out.println("<{>");
out.println("<function f1() {>");
out.println("<alert('Select data');>");
out.println("<}>");
out.println("</script>");
out.println("</head>");
out.println("</head>");
out.println("<body>");
out.println("<center><u><h1>User Data</h1></u>");
out.println("<form name='form' >");
out.println("<table border="+2+ "> ");
out.println("<tr>");
out.println("<td> Select </td>");
out.println("<td> Name </td>");
out.println("<td> Roll No. </td>");
out.println("<td> Class </td>");
out.println("<td> Mobile Number </td>");
out.println("</tr>");
String nm = req.getParameter("name");
String roll = req.getParameter("roll");
String clas = req.getParameter("clas");
String mono = req.getParameter("mono");
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch(ClassNotFoundException ex) {
System.out.println("driver not loaded");
System.exit(0);
}
String URL = "jdbc:oracle:thin:@192.168.106.87:1521:ora11g";
String Username = "pratik";
String Password = "pratik";
//Insert
try {
con = DriverManager.getConnection(URL,Username,Password);
if(req.getParameter("choise")==null) {
ps = con.prepareStatement("INSERT INTO student (name, rollno, class, mobileno) VALUES (?, ?, ?, ? )");
ps.setString(1,nm);
ps.setString(2,roll);
ps.setString(3,clas);
ps.setString(4,mono);
int i = ps.executeUpdate();
pwinsert.println(i);
if(i!=0) {
pwinsert.println("data has been stored");
}
else {
pwinsert.println("data could not be stored");
}
}
}
catch(Exception e) {
pwinsert.println(e.getMessage());
}
String idr=null;
//Delete
//cond. nt neeeded (null)
if(req.getParameter("choise")!=null) {
nm = req.getParameter("choise");
idr = "DELETE from student WHERE name ='"+nm+"'";
try {
st=con.createStatement();
rs = st.executeQuery(idr);
}
catch (Exception e) {
e.getMessage();
System.out.println("Error " +e);
}
System.out.println("Data se deleted...");
}
//Update
/* String updt = "UPDATE student SET name ='"+nm +"',rollno='" + roll + "', class='"+ clas +"', mobileno='"+mono+"' WHERE name ='"+nm +"' ";
PreparedStatement ps1 = null;
try {
ps1=con.prepareStatement(updt);
} catch (SQLException e2) {
e2.printStackTrace();
}
int i = 0;
try {
i = ps1.executeUpdate();
} catch (SQLException e1) {
e1.printStackTrace();
}
if(i==1)
out.println("success");
else
out.println("failed");
*/
// edit
if(req.getParameter("choise")!=null) {
nm = req.getParameter("choise");
idr = "UPDATE student SET name = ?, rollno = ?, class = ?, mobileno = ? WHERE name = ?";
try {
st=con.createStatement();
int rs1 = st.executeUpdate(idr);
}
catch (Exception e) {
e.getMessage();
System.out.println("Error " +e);
}
System.out.println("Data Edited...");
}
else {
System.out.println("Select row..");
}
/* String upd = "UPDATE student SET name = ?, rollno = ?, class = ?, mobileno = ? WHERE name = ?";
PreparedStatement prest = null;
try {
prest = con.prepareStatement(upd);
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
prest.setString(1,"nm");
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
prest.setString(2,"roll");
} catch (SQLException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
prest.setString(3,"clas");
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
prest.setString(4,"mono");
} catch (SQLException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
prest.executeUpdate();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
System.out.println("Updating Successfully!");
*/
idr = "SELECT * FROM student WHERE name IS NOT NULL";
try {
st=con.createStatement();
rs = st.executeQuery(idr);
}
catch (Exception e) {
e.getMessage();
System.out.println("Error " +e);
}
try {
while (rs.next()) {
out.println("<tr>");
out.println("<td>" + "<input type=\"radio\" name=\"choise\" value=\"" + rs.getString(1) + "\" /> </br>" + "</td>");
out.println("<td>" + rs.getString(1) + "</td>" + "\t <td>" + rs.getInt(2) + "</td>" + "\t <td>" + rs.getString(3) + "</td>" + "\t <td>" + rs.getString(4));
out.println("</tr>");
}
out.println("<tr>");
out.println("<td> </td>");
{
out.println("<td>" + "<input type=\"submit\" value=\"Delete Data\" />" + "</td>");
if(req.getParameter("choise") != null) {
out.println("submitted.");
}
else {
out.println("<script>alert('Data stored into database')</script>");
}
}
// To Edit
out.println("<td>" + "<input type=\"button\" value=\"Edit \" onClick = f1() />" + "</td>");
out.println("<td> </td>");
out.println("<td> </td>");
out.println("</tr>");
}
catch (Exception e) {
e.getMessage();
System.out.println("Error" +e);
}
try {
rs.close();
}
catch (Exception e) {
e.getMessage();
System.out.println("Error" +e);
}
try {
st.close();
}
catch (Exception e) {
e.getMessage();
System.out.println("Error" +e);
}
out.println("</table>");
out.println("</form>");
out.println("</center>");
out.println("</body>");
out.println("</html>");
out.close();
}
}