更新/编辑从数据库输入的数据-Servlet [英] Update/Edit entered data from database - servlet
本文介绍了更新/编辑从数据库输入的数据-Servlet的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我已经准备好用于插入，查看和删除数据的表格 现在我想添加选项来编辑该数据，但是要么我遵循错误的方式来做，要么不知道该怎么做.
I have prepared a form for inserting, viewing and deleting data and now I want to add option to edit that data but either I am following wrong way to do it or I dont know how to do that.
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页面进行编辑还是新页面或.. ?? 我知道我还没有遵循MVC的结构，但是我想在单个页面中进行整个编码，所以需要帮助. 谢谢.
So can any one help me proceeding to edit the entered data ?? Should I give reference to old html page to edit or new page or .. ?? I know I haven't followed MVC structure but I wanted to do whole coding in single page so waiting for help.. Thank you.
这些是我的代码.
Datastore.html
Datastore.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>
DataInsertTable.java
DataInsertTable.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();
}
}
推荐答案
首先在页面HTML页面上创建一个隐藏字段，以标识要执行的操作
最初，其值应为空，并根据单击是否为插入更新或删除操作为所有可用操作分配一些唯一值.然后从servlet中将该字段获取为req.getParameter("<HIDDEN FIELD NAME>")，并基于此将您的代码分别放入if和else if块中以便仅运行该代码.
希望这会有所帮助
firstly on the page HTML page create one hidden field to identify which operation you want to perform
initially its value should be blank and based on click whether insert update or delete assign some unique values to all the available operations.and from your servlets get that field as req.getParameter("<HIDDEN FIELD NAME>")and based on that put your code in respective if and else if block so that only that code will run.
hope this will help
这篇关于更新/编辑从数据库输入的数据-Servlet的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
