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?
Related
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)
i am having f.jsp which returns a lists of ages(1..100) and genders(m/f) and a button GO and put it in comboboxes and i have f_m.java which is servlet which took the selected items from comboboxes and select an certain item from database and put it in table in f.jsp .. now my problem is when trying to print the table in f.jsp and HTTP 500 appears so what can i do .. here is my code
f.jsp
<% List<String> sex = (List<String>)request.getAttribute("sexList"); %>
<% List<String> age = (List<String>)request.getAttribute("ageList"); %>
<form method ="GET" action="f_m" >
<html>
<body>
<table>
<tr>
<td>Gender:</td>
<td><select name="sex">
<%for(String item : sexList) { %>
<option value="<%=item%>"><%=item %></option><%}%>
</select>
</td>
<td>age:</td>
<td><select name="age">
<%for(String item : maritalStatus) { %>
<option value="<%=item%>"><%=item %></option><%}%>
</select>
</td>
<td><input type="submit" value="Go" name="Go"></td>
</tr>
</table>
</form>
</body>
</html>
and f_m.java
String gender = request.getParameter("sex");
String age = request.getParameter("age");
if(request.getParameter("Go") != null){
// i want to go to f.jsp to print the table
}
You must set the request attributes in the servlet before forwarding to the jsp. I suppose it could be something like :
// prepare the attributes
int ageList = new int[100];
int sexList = new String[]{"m", "f"};
for (int i=0; i<100; i++) { ageList[i] = i + 1; }
// put them in request
request.setAttribute("ageList", ageList);
request.setAttribute("sexList", sexList);
// and forward to the jsp.
request.getRequestDispatcher("f.jsp").forward(request, response);
You have two lists: sex and age. When you are trying to populate the select, you asked:
<%for(String item : sexList) { %>
Where is declared your sexList? May be you want to iterate through sex list? I mean, try:
<%for(String item : sex) { %>
And the same for second list:
<%for (String item : age) {%>
You must be more explicit what are you trying to do in your Servlet. I assume your main scope is to populate two selects in a form depending on two lists: sex and age. After this you want to take 2 selected values and pass them to servlet, the servlet will make a call to a database depending on these two values and will return a row from the table. After this you want to print this row in your f.jsp. If so, get the values from the select (and populate them right, like i mentioned below) in your servlet:
String sex = request.getParameter("sex");
String age = request.getParameter("age");
//method to call database, i.e List<Persons> list = DBHelper.checkSomething(sex, age);
if(...){
RequestDispatcher rd = request.getRequestDispatcher("f.jsp");
request.setAttribute("list", list);
rd.forward(request, response);
}
And i strongly recommend you to print your data based on a View. If you want to know more, read about MVC patterns.
The code for retrieving data from database into Drop Down List.
<%
DataSource data = new MysqlDataSource();
Connection con = data.getConnection("root","system");
System.out.println("Connected to MySQL");
PreparedStatement pre = con.prepareStatement("select * from library.booklist");
ResultSet result = pre.executeQuery();
%>
<tr>
<font color="black" size="5"> <td> Book List : </td> </font>
<td> <select name= "BookList" id="booklist" onchange="show()">
<option> - select - </option>
<%
while (result.next())
{
String name = result.getString("Book");
System.out.println("Output Done");
%>
<option value="<%=name%>"> <%=name%></option>
<%
}
%>
</select></td>
</tr>
<tr>
<%
/* my code for displaying quantity is below but it's not working. I am new to jsp, so don't know how to populate the textbox. */
String value = request.getParameter("BookList");
pre = con.prepareStatement("select Quantity from library.booklist where Book = ? ");
result = pre.executeQuery();
%>
<font color="black" size="5"><td> Quantity : </td>
<%
while (result.next())
{
int quantity = result.getInt("Quantity");
System.out.println("quantity dikha raha hai");
%>
<input name = "Quantity" type = "text" size = "25" readonly = "readonly" value = "<%=quantity%>"> <%=quantity%> </input>
<%
}
%>
</td>
</tr>
Edit
You need to pass your BookList parameter to your prepared statement:
String value = request.getParameter("BookList");
pre = con.prepareStatement("select Quantity from library.booklist where Book = ? ");
pre.setString(1, value); // <------
result = pre.executeQuery();
Otherwise your query does not know which Book to select.
Original
You haven't said what the actual problem is, but your HTML markup has problems that definitely aren't helping.
Don't use the <font> tag. It is not supported in
HTML5.
Your second <font> needs a closing </font>.
You have a closing </td> tag at the end with no opening <td>.
The <input> tag is a void element, meaning it does not accept content between opening and closing tags. Write it as <input type="text" name="Quantity" .../>
Clean up those things and your problem might be fixed, or at least more obvious.
Hello fellow stack overflowers.
I am stuck on a certain portion of a project and am looking for some advice.
I have a photo gallery page in jsp that is set up to display all the listings of photo albums and the photos within them based on the user's interest. It is currently set up so that whatever 'photo' option is selected will be redirected to another jsp with the outputstream decoding on that particular page. However, in order to see another photo or image, the user has to go 'back' to the photo galleries page and select another image for a new photo.
Is there a way to set up the galleries page so that all the photos can be dynamically displayed on the page OR is there possibly a way put some direction on the display.jsp page so that the user can simply click from one photo to the next?????
Code is below.
<div id="subSlideshow">
<table>
<tr>
<td id="subpageSlideshow">
<table>
<tr>
<td>
<h1 id="subpageTitle">Galleries</h1>
<form action="gallery" method="get">
<%try{
Connection conn = GalleriesConnection.connect();
Statement st = conn.createStatement();
String sql = "SHOW TABLES IN GALLERIES;";
ResultSet rs = st.executeQuery(sql);
while(rs.next()){%>
<input class="wineDiv" type="submit" name="gallery" value="<%=rs.getString(1).toLowerCase() %>" />
<%}
rs.close();
st.close();
GalleriesConnection.close(conn);
}
catch(Exception e){
}%>
</form>
<td>
</tr>
<tr>
<td>
<h1 id="subpageTitle">Images</h1>
<form action="pictures/display.jsp">
<%try{
Connection conn = GalleriesConnection.connect();
Statement st = conn.createStatement();
String sql = "SELECT PHOTO_NAME FROM "+gallery+" ;";
ResultSet rs = st.executeQuery(sql);
while(rs.next()){
String photoName = rs.getString(1);
%>
<input class="wineDiv" type="submit" name="photo" value="<%=photoName %>" />
<% }
rs.close();
st.close();
GalleriesConnection.close(conn);
} catch(Exception e){
}%>
</form>
</td>
</tr>
</table>
</td>
<td id="subpageInfo">
<h1 id="subpageTitle">Click on an image to see a larger view</h1>
<div id="slider">
<script src ="js/slides.js" type="text/javascript"></script>
<img id="1" src="pictures/winery_image1.jpg" />
<img id="2" src="pictures/winery_image2.jpg" />
<img id="3" src="pictures/winery_image3.jpg" />
<img id="4" src="pictures/winery_image4.jpg" />
<img id="5" src="pictures/winery_image5.jpg" />
</div>
<input class="previous" onclick="prev(); return false;" value="Previous Image" />
<input class="next" onclick="next(); return false;" value="Next Image" />
</td>
</tr>
</table>
</div>
All the action on the page is within this div. The first connection command retrieves all the table names in the database and spits the table names out on submit buttons. Additionally, the images currently listed in the subpageInfo are one of the desired spots on where I would like images from the database to be embedded. They make a nice little fadeOut() fadeIn() transition when the next and previous buttons are selected.
The second connection gets all the names of the photos and puts them in the form of submits as well. Selected photo names are sent to this page:
<%# page import="java.sql.*"%>
<%# page import="java.io.*"%>
<%
byte[] imgData = null;
%>
<jsp:scriptlet>
String photo = request.getParameter("photo");
</jsp:scriptlet>
<%
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:8889/GALLERIES","myusername","mypassword");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT PHOTO FROM PHOTOS WHERE PHOTO_NAME = '"+photo+"';");
while (rs.next()) {
Blob image = rs.getBlob(1);
imgData = image.getBytes(1,(int)image.length());
}
// display the image
response.setContentType("image/png");
OutputStream o = response.getOutputStream();
o.write(imgData);
o.flush();
o.close();
rs.close();
stmt.close();
con.close();
} catch (Exception e) {
out.println("Unable To Display image");
out.println("Image Display Error=" + e.getMessage());
return;
}
%>
This program does everything it is asked to do, but I am having some difficulty on making it more user friendly. The desired effect is either embed the images in the subpageInfo div or to have some directives on the display.jsp page to go from one image to the next.
As always any and all help is greatly appreciated.
If you want to present a set of pictures I'd go for:
http://lokeshdhakar.com/projects/lightbox2/
Or if you want to do everything yourself, use only one page - use the selection form you mentioned and after sumbition, reload the same page including a decoded image into it. You can setup a javascript so that everytime user selects another picture the form gets submited so user doesn't have to click submit.
But I suggest rethinking the whole thing. What's your goal? Is this approach the best one? I'm usually way too deep in technical stuff that I don't see the solution user expects. That's why I ask random people to help me out.
Also - scriptlets? ew! Use JSTL and prepare everything in the controller. Or use Primefaces, JSF, managed beans and all the stuff that was made for this purpose.
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.