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How to get input value from one jsp page to another jsp page?

I am trying to get a one-page input value to another page while clicking the order button.
while I will take a number of item value and click the order button, it will carry the value the order page. The page code is here,
<td><%=rs.getString("product_price")%></td>
<td> <input type="number" name="no_item" value="1" /></td>
<td class="text-center" width="250">
Order
Edit
Delete
</td>
The order page code is here,
<%
statement = connection.createStatement();
String u=request.getParameter("u");
String item_num =request.getParameter("no_item");
int num=Integer.parseInt(u);
String Data = "select * from products_tbl where id='"+num+"'";
rs = statement.executeQuery(Data);
String product_price;
while (rs.next()) {
%>
<input type="hidden" name="id" value='<%=rs.getString("id")%>'/>
<div class="form-group">
<h4 style="float:left; padding-right:8px;">Product Name:</h4> <h4> <%=rs.getString("product_name")%> </h4>
</div>
<div class="form-group">
<%
product_price = rs.getString("product_price"); int num1 = Integer.parseInt(product_price); %>
</div>
<%= item_num %>
<%= num1 %>
<%
}
%>

Onclick of order button add the input value in url query string. you have need to use java script in jsp page.
<script>
function order(page, id){
input_value = document.getElementById('no_item').value;
location.href= page+"?u="+id+"&no_item="+input_value;
}
</script>
Add the onclick function within order button.
<a onclick="order('order.jsp', '<%=rs.getString("id")%>')" class="btn btn-success">Order</a>
In order.jsp page you will get the input value.
request.getParameter("no_item");

Why is the delete function not working in my jsp file?

I have created a table to display data and there is a checkbox next to each of the data. I want to create a function where if the user click the checkbox of that data and press the delete button, the data will be remove from the table and the database. I have came up with the code but it doesn't remove the data. What is the problem with my code ?
Display on Webpage
HTML
<%
String id = request.getParameter("hiddenID");
String sql1="";
{
sql1 = "select * from exercise1";
PreparedStatement pstmt1=conn.prepareStatement(sql1);
ResultSet rs1 = pstmt1.executeQuery();
while(rs1.next()){
String arm = rs1.getString("Arm");
String time1 = rs1.getString("Time1");
out.println("<tr>");
out.println("<td style = 'width: 20%'>");
out.println(arm);
out.println("</td>");
out.println("<td style = 'width: 5%'>");
out.println(time1);
out.println("</td>");
%>
<td style="width: 5%"><input class="mychkbox" type="checkbox"
value="<%=id%>" form="multipleDele" name="DeleteChkbox" /></td>
<%
out.println("</tr>");
}
conn.close();
}
%>
This is my delete.jsp file
<%
String[] id = request.getParameterValues("DeleteChkbox");
int count=0;
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
// Step 2: Define Connection URL
String connURL = "jdbc:mysql://localhost/medicloud?user=root&password=root";
// Step 3: Establish connection to URL
conn = DriverManager.getConnection(connURL);
if (id != null)
{
for(int i=0;i<id.length;i++){
String sqlStr = "DELETE from exercise1 WHERE id=?";
PreparedStatement pstmt = conn.prepareStatement(sqlStr);
pstmt.setInt(1, Integer.parseInt(id[i]));
//pstmt.setInt(1, Integer.parseInt(id[i]));
int rec=pstmt.executeUpdate();
if (rec==1)
count++;
}
}
//System.out.println(functions);
%>
<form action="exercise.jsp" method="post">
<label><%=count%> record(s) deleted!!</label>
<input type="submit" value="Return" name="ReturnBtn" />
</form>
<%
conn.close();
} catch (Exception e) {
out.println(e);
}
%>

The id you are writing to the checkbox value is not coming from the database results. It is being retrieved in the JSP from a request parameter:
String id = request.getParameter("hiddenID");
... and then being written to every checkbox field:
<input class="mychkbox" type="checkbox" value="<%=id%>" form="multipleDele" name="DeleteChkbox" />
You aren't writing a different id for each checkbox.
As such, it probably is not the id of any of the database records, and therefore none of them are being deleted.
You should be reading the id of each record in your while loop when building the HTML.
I suspect you need something like this:
<input class="mychkbox" type="checkbox" value="<%=rs1.getString("id")%>" form="multipleDele" name="DeleteChkbox" />

Your image has three columns: arm exercises, number of times and action. The DeleteChkboox field will only tell you if the field is selected or not for a particular row. You need to get the ids that have been selected for deletion. Unchecked checkboxes will not show up in an array of checkboxes so your form has to take this into account. It needs to look something like
<form action = "...">
<input type="submit" value="delete">
<input type="submit" value="assign">
<table>
<c:forEach items="${ records }" var="r">
<tr>
<td>
${ r.exercise }
</td>
<td>
${ r.times }
</td>
<td>
<input type="checkbox" value="${ r.id }" name="userAction">
</td>
</tr>
</c:forEach>
</table>
</form>
Then you need to change your jsp so that you get the ids of the selected rows. Change the jsp part that iterates your ids to
<%
// get array of ids
String[] ids = request.getParameterValues("userAction");
int count=0;
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
// Step 2: Define Connection URL
String connURL = "jdbc:mysql://localhost/medicloud?user=root&password=root";
// Step 3: Establish connection to URL
conn = DriverManager.getConnection(connURL);
if (ids != null) {
for(int i=0; i < ids.length; i++) {
String sqlStr = "DELETE from exercise1 WHERE id=?";
PreparedStatement pstmt = conn.prepareStatement(sqlStr);
pstmt.setInt(1, Integer.parseInt(ids[i]));
int rec=pstmt.executeUpdate();
if (rec==1) {
count++;
}
}
}
}
%>
That aside, it's generally not the best of ideas to be running sql updates in jsps if you can help it. Consider moving this logic to a controller class and using the jsp layer for presentation only.
EDIT
As per your comment "it's not working", instead of looking at this particular problem (why doesn't the code you wrote remove the data) you have to look at the bigger picture: what is the problem you are trying to accomplish?
It looks something like this, in plain English:
Show a user a set of records
Allow the user to mark the records they'd like to delete (array of checkboxes); allow the user to submit this information (the record ids)
Process (delete) the submitted ids
Step 1
Iterate over a list of records in jsp, inside a <form> element
For each record, create a checkbox whose value is that record's id
Step 2
Add a delete button allowing the user to submit the form of ids
Step 3
Process the submitted information: get the list of ids submitted in the request, iterate over it and delete the records one by one
Which step are you stuck on?

Inserting into database from input by clicking a button

I have done the entire coding but data isnot getting inserted in the database
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection connection =
DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/userinfo?user=root&password=admin");
Statement statement = connection.createStatement() ;
resultset = statement.executeQuery("select * from item") ;
Now this is the part where i have done the connection and i think it is okay because in first part where i display values from database it is working
Now that i have done this in the next part i have taken input values from input boxes
<input type="submit" value="RECEIVE" style="width:100px; height:40px"
name="receive ">
now <%
PrintWriter pw = response.getWriter();
PreparedStatement pst = null;
if(request.getParameter("receive")!=null)
{
String dob=request.getParameter("datepicker");
String supplier=request.getParameter("supplier");
String type=request.getParameter("type");
String quantity=request.getParameter("quantity");
String queryString = "INSERT INTO stock_quantity values(?,?,?,?)";
pst = connection.prepareStatement(queryString);
pst.setString(2,dob);
pst.setString(3,supplier);
pst.setString(4,type);
pst.setString(5,quantity);
int i = pst.executeUpdate();
if(i!=0){
%>
<script language="javascript">
alert("Send sucess");
</script>
<%
}
else{
%>
<script language="javascript">
alert("Enter all data");
</script>
<%
}
}
%>
The data doesnt gets inserted.. Find the problem in the code

Don't make connection with db in first controller(in your case in jsp), just send your data to another controller, and there you can insert it to db. You can use either #Requestparam("param") to get single parameters, or #ModelAttribute("name") to get entire POJO object(where you will have your all parameteres).
So your html file would look like (in thymeleaf) you need to change some of thymeleaf things to jsp:
<form action="#" th:action="#{/save}" th:object="${yourObject}" method="post">
<div>
<label for="quantity">quantity:</label>
<input type="quantity" th:field="*{quantity}">
</div>
<button type="submit">Submit</button>
</form>
And your second controller:
#PostMapping("save")
public String reset(#ModelAttribute(value = "yourObject") YourPOJOClass request) {
//save to DB
}
If you want to accept parameters, not entire object, add name parameter to jsp/html
for example:
<div>
<label for="quantity">quantity:</label>
<input type="quantity" th:field="*{quantity}" name="quantity">
</div>
And in controller you can get this parameter like that:
#PostMapping("save")
public String reset(#RequestParam("quantity") String quantity)

How to pass a value from one jsp to another jsp page?

I have two jsp pages: search.jsp and update.jsp.
When I run search.jsp then one value fetches from database and I store that value in a variable called scard. Now, what I want is to use that variable's value in another jsp page. I do not want to use request.getparameter().
Here is my code:
<%
String scard = "";
String id = request.getParameter("id");
try {
String selectStoredProc = "SELECT * FROM Councel WHERE CouncelRegNo ='"+id+"'";
PreparedStatement ps = cn.prepareStatement(selectStoredProc);
ResultSet rs = ps.executeQuery();
while(rs.next()) {
scard = rs.getString(23);
}
rs.close();
rs = null;
} catch (Exception e) {
out.println(e.getLocalizedMessage());
} finally {
}
%>
How can I achieve this?

Using Query parameter
<a href="edit.jsp?userId=${user.id}" />
Using Hidden variable .
<form method="post" action="update.jsp">
...
<input type="hidden" name="userId" value="${user.id}">
you can send Using Session object.
session.setAttribute("userId", userid);
These values will now be available from any jsp as long as your session is still active.
int userid = session.getAttribute("userId");

Use sessions
On your search.jsp
Put your scard in sessions using session.setAttribute("scard","scard")
//the 1st variable is the string name that you will retrieve in ur next page,and the 2nd variable is the its value,i.e the scard value.
And in your next page you retrieve it using session.getAttribute("scard")
UPDATE
<input type="text" value="<%=session.getAttribute("scard")%>"/>

Use below code for passing string from one jsp to another jsp
A.jsp
<% String userid="Banda";%>
<form action="B.jsp" method="post">
<%
session.setAttribute("userId", userid);
%>
<input type="submit"
value="Login">
</form>
B.jsp
<%String userid = session.getAttribute("userId").toString(); %>
Hello<%=userid%>

How can I send data from one JSP page to another JSP page?
One of the best answer which I filtered out from above discussion.
Can be done in three ways:
using request attributes:
Set the value to send in request attribute with a name of your choice as request.setAttribute("send", "valueToSend") and retrieve it on another jsp using request.getAttribute("send");
using session attributes
Similar to above but using session object instead of request.
using application attributes
Same as 1 and 2 above but using application object in place of request and session.

Suppose we want to pass three values(u1,u2,u3) from say 'show.jsp' to another page say 'display.jsp'
Make three hidden text boxes and a button that is click automatically(using javascript).
//Code to written in 'show.jsp'
<body>
<form action="display.jsp" method="post">
<input type="hidden" name="u1" value="<%=u1%>"/>
<input type="hidden" name="u2" value="<%=u2%>" />
<input type="hidden" name="u3" value="<%=u3%>" />
<button type="hidden" id="qq" value="Login" style="display: none;"></button>
</form>
<script type="text/javascript">
document.getElementById("qq").click();
</script>
</body>
// Code to be written in 'display.jsp'
<% String u1 = request.getParameter("u1").toString();
String u2 = request.getParameter("u2").toString();
String u3 = request.getParameter("u3").toString();
%>
If you want to use these variables of servlets in javascript then simply write
<script type="text/javascript">
var a=<%=u1%>;
</script>
Hope it helps :)

Edit and update same textbox

I have a database Table where I can edit a value. I want to update the same, below is the code that I have tried.
The table code is as below
<table border="1px">
<tr>
<td><b>DBID</b></td>
<td><b>Query Raised</b></td>
<td><b>Time Raised</b></td>
<td><b>Query Answered</b></td>
<td><b>Time Answered</b></td>
</tr>
<%
try {
ps = con.prepareStatement("Select DBID, Query_Raised, TR, Query_Answered, TA from Scope1 where TR!='null'");
rs = ps.executeQuery();
while(rs.next()) {
%>
<tr>
<td><%=rs.getString("DBID")%></td>
<td><input type="Text" value="<%=rs.getString("Query_Raised")%>" name="Updat"></td>
<td><%=rs.getString("TR")%> </td>
<td><%=rs.getString("Query_Answered")%></td>
<td><%=rs.getString("TA")%></td>
<td><input type="Submit" value="Update"></td>
</tr>
<%
} // while loop ends here
rs.close();
con.close();
} catch(Exception e) {
out.println(e);
}
%>
</table>
and the update query that is used is:
String a = request.getParameter("Updat");
ps = con.prepareStatement("Update Scope1 Set Query_Raised = '" + a + "'");
int i = ps.executeUpdate();
if(i == 1) {
out.print("Done");
} else{
out.print("Erro");
}
I wanted to know the where condition that I should use to update the data in same page.
Thanks

I understand the first code part in the question is a JSP say update.jsp and the second part it seems is your servlet, say UpdateServlet.
So in your update.jsp on every row you have an <input type="text"> and submit button, but the <form> I think is only one which must be outside the <table>, so here goes my solution (choose any one):
Use multiple <form> tags for each row, like
<form action="whatever_action_you_have_which_calls_the_servlet"
name="form<%=rs.getString("DBID")%>"
id="formID<%=rs.getString("DBID")%>">
// Including name and id so that the different forms remain unique
<tr>
<td><%=rs.getString("DBID")%></td>
<td><input type="Text" value="<%=rs.getString("Query_Raised")%>" name="Updat"></td>
<td><%=rs.getString("TR")%> </td>
<td><%=rs.getString("Query_Answered")%></td>
<td><%=rs.getString("TA")%></td>
<td><input type="Submit" value="Update"></td>
</tr>
</form>
So when you click on submit it would submit the <form> for which the submit button was clicked and would submit only the input which was edited and voila! your servlet code also works fine.
You can have both the blocks of code in the same JSP, then use the <form> code snippet as described in point#1 and the second code snippet would be:
String a = request.getParameter("Updat");
if ( (a is not empty) or (a is not null) ) {
ps = con.prepareStatement("Update Scope1 Set Query_Raised = '" + a + "'");
int i = ps.executeUpdate();
if(i == 1) {
out.print("Done");
} else{
out.print("Error");
}
}
...
<form action="whatever_action_you_have_which_will_call_this_JSP" ...>
<tr> ... your code as in point#1
</tr>
</form>
Use ajax and other javascript DOM manipulative methods to accomplish this as said by Endy.
For this you will need to have JSP (to display) & Servlet (to update the code).
This might be a little more effort but you will learn Ajax and will be a little more close to real world.
By far jQuery ajax is the simplest to use.
Note:
Just for the record, I know you might be practicing but if you are planning to use it in a real project then please read ahead.
It is a bad-practice to use scriptlets in JSP (unless really required and that too if it is for view-level logic and not business or data-level logic) and even worse is to use JDBC code inside a JSP. So it would be really great if you could follow f_puras's advice.
If you are wondering why I should listen to your unsolicited advice then here is some food for thought:
How to avoid scriptlets in JSP
Scriptless JSPs
Why JSP = JDBC is bad
Hope this helps.

You can either use AJAX to post the data to a page that handles the updating, then return the result as a callback, see http://api.jquery.com/jQuery.post/.
Other solution is to forward user back to the page with the form after you have processed the submission.
Third solution is to submit the data to the same page and parse/update it there.