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Get value of <td> in Java - request.getParameter

Im trying to get the values of some td elements where the data consist of data from MySQL table. It displays the data fine in my browser (e.g. if i change type from "hidden" to "submit"), but when I try to get the value i only get null.
Here are my jsp and it displays the correct results in the browser.
<td>
<form action="history.jsp" method="get">
<input type="hidden" name="res" value="<%=his.getRes()%>"/>
</form>
</td>
When i try to print the values however, I only get "null" at of evey :
<%
String res = request.getParameter("res");
System.out.print(res);
%>
I'm still very new, so it's proberly a straight forward answer. Thank you in advance for the help.

I suggest that you change the name of your variable :
String newname = request.getParameter("res");
System.out.println(newname)

One can submit (=send) only one <form>. So one must assume there is just one single td with one <form>. Forms also may not be nested in an outer form.
It need some way to submit the form.
So experiment first with:
<td>
<form action="history.jsp" method="get">
<input type="text" name="res" value="<%=his.getRes()%>"/>
<input type="submit" value="Send"/>
</form>
</td>
This will show whether his.getRes() yielded something. And allows a manual submit in the browser.

Spring, Java, HTML: How can I populate an HTML form with values?

I want to write a part of a website that lets the user alter the data of a pre existing book. For that, I am trying to use a form which works fine. I just can't figure out how to get the form to display data in the editing fields so the user doesn't have to enter everything again but can simply change some details. My HTML code looks like this:
<form method="post" role="form" class="ui form" id="bookForm" th:action="#{/editBook}" th:object="${bookForm}">
<div class="field">
<label for="name">Book</label>
<input id="name" name="name" th:field="*{name}" th:errorclass="fieldError" type="text" required="required"/><br/>
</div>
I include some more code about errors and other things but this is basically where I want the form not only to pass values to my java file but also to take values about the book and display them in the editing fields.
I think I need to pass the book that the user wants to edit into this form but I'm not sure how. I have tried:
<input type="hidden" id="currentBook" name="currentBook" th:value="${currentBook}"/>
right before the "div" statement and then passing the "currentBook" into HTML with
model.addAttribute("currentBook", currentBook);
in my #GetMapping method of that website. I then changed the "input" statement in my field as well to
<input id="name" name="name" th:field="*{name}" th:value="${currentBook.name}" th:errorclass="fieldError" type="text" required="required"/><br/>
currentBook.name will give me the name of that book just not within this context. Does anyone know what I'm doing wrong and how it will work?
Thank you in advance!

How to generate edit modals for each element in the model?

I'm trying to use thymeleaf to generate edit and delete modals for each element in the model in my ModelAndView using th:each.
The modals are indeed created and have unique ids based on the id field of the elements. The problem I have is none of the values from elements are parsed into the inputs to enable the user to see the current values.
They are obviously there because the view also has a table which displays each element's values along with the anchors which toggle the modals.
Here's some example code of how I'm doing it:
<div th:each="f : ${foos}" th:id="um- + ${f.id}" class="modal fade"
tabindex="-1" role="dialog">
...
<form role="form" th:action="#{/foo/update}" th:object="${foo}" th:method="post">
<input type="hidden" th:field="*{id}" th:value="${f.id}"/>
<fieldset class="form-group">
<label for="bar">Bar</label>
<input th:field="*{bar}" th:value="${f.bar}" class="form-control"
id="bar" type="text" placeholder="Bar"/>
</fieldset>
...
</form>
...
</div>
How to generate edit modals for each element in the model? I'm not sure why thymeleaf is unable to get the values of the fields from the model elements.

That's not a great approach actually. In addition to it not working, doing using a loop obviously creates n modals for the collection.
The solution that worked best was to provide a single modal that would be populated and submitted with Ajax calls.
This no-frills Spring Boot app has all the relavant code.

How to send label parameter from JSP to servlet?

I have a jQuery dialogue box which contains values as checkboxes. On selecting the checkboxes I am storing the selected values into label. Next I have to send these values from label as parameter through form to servlet but I don't know how to complete it.
Here is my code:
<form action="CallTimer" method="GET">
<label class="button2">Set Date: </label>
<input type="text" name="date" id="date" size="4">
<input type="Submit" name="Submit" value="Submit" id="Submit">
<br/>
Select Reporting Level
<label class="button2" style="display:none" id="depart"> Department</label>
</form>
I am retrieving these parameters in my Servlet as:
String reportname=request.getParameter("depart");
System.out.println(reportname);
But it is returning null values. Please help me.
Thanks in advance.

You have to use hidden input field:
<input type="hidden" name="depart" />

You need to understand what gets passed on form submission and what is not. In a nutshell, only values of the input fields get sent to the server. You have several ways to solve your problem:
Write value to a hidden input field
Modify the query string (what gets sent after ? in your GET request) during form submission (using java script):
?...&depart=xxx

How to get the value of drop down list?

I want to get the value to of drop down list, to send back to server to match something.
Update:
Sorry, i has to be clear on my question. I am using javascript to get values in client side and sending those back to server with DWR & processing them with JAVA code.
<select><option selected="selected" value="1">EEE</option><option value="2">ECE</option><option value="3">IT</option><option value="4">CSE</option><option value="5">MECH</option></select>
'
<input id="id" type="text" size="5"/>
<input id="name" type="text" size="15"/>
<input id="age" type="text" size="5"/>
<input id="age" type="text" size="5"/>
'
I want to get the values(1,2,3,4,5) ALONG with the other Name, Id, Age values.
I can get field text using dwr.util.getValues().
How can I get that select option value?

Since you specify no server-side language, I assume you want in HTML/JS. So, use this code in javascript, assuming the ID of your combobox is combo1:
<script type="text/javascript">
var combo1 = document.getElementById("combo1");
var val = combo1.options[combo1.selectedIndex].text;
//this will show the value in a Dialog Box
alert(val);
</script>

<select id="id"> ...
var opts = dwr.util.byId("id").options;

Try giving your select element a name attribute:
<select name='department'>...