I am trying to display data in JSP and i am wondering if there is a better way then what i have done. I am not really experienced in Java or JSP so the code i made is probably not the cleanest.
I will only be returning count from my database as shown below so i will not be returning huge amounts of data i just need the number of rows from the database to display in my divs.
Would appreciate any help if anyone has any ideas but functionally what i have at the moment works good and without any problems i am just worried about security and how messy the code is. I am using Hibernate framework for this project.
My method that returns data from database:
public Long findCount() {
Session session = openCurrentSession();
Query result = session.createQuery("SELECT COUNT(*) FROM Polica", Polica.class);
Long count = (Long)result.uniqueResult();
return count;
}
data.jsp this is where i display count from database currently there is only 1 but there will be multiple here so i am wondering also if there is a way to call specific one using ajax.
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<%#page import="digiwallboard.Service.PolicaService" %>
<%#page import="digiwallboard.Config.*" %>
<%#page import="digiwallboard.DAO.PolicaDAO2" %>
<%#page import="digiwallboard.DAO.PolicaDaoInterface" %>
<%#page import="digiwallboard.Entity.Polica" %>
<%#page import="java.util.*" %>
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<p><%=PolicaService.findCount() %></p>
</body>
</html>
And finally my ajax call:
function refresh() {
$.ajax({
url: "data.jsp",
type: 'GET',
success: function(res) {
$('.result').html(res);
}
});
}
Related
How about community, this error happened to me today and I would like to know if some of you ever happened to you and how to solve it. I am creating an application with servlets in java that the functionality is to have a button, where by clicking it sends me a json with 50 records through the URL so that I can generate an excel. Now, all good when it comes to 10 records, no problem happens, when you have more than 20 records in that json or so, that's where the error happens to me. Investigating I found that the error happens because the header I am sending is too long. Here is an example of what the header I'm sending is:
Url: localhost:8080/pruebas/vistas/excel/Reporte_Insertados.jsp?registros=[{"CODPER":"123456","NRO":"1","DNI":"45874587","APELLIDOS_NOMBRES":"ROJAS%20LOPEZ%20GUSTAVO","FECHA":"14/01/2020","MONTO":"150.50","OBSERVACION":"DADSADSA","RAZON_SOCIAL":"","ESTADO":"DATOS%20CORRECTOS","":""}...] so until you have 50 records.
So my question is: If any of you solve it or how could I do it from my servlet to allow the header to be long, since it is the problem for which it does not leave me and the error happens to me.
I leave code of my application. Thank you in advance community.
My Javascript code:
function exportarReporteInsertados(registrosInsertados){
let tabla_reporte_insertados = $("#tablaCargaMasiva").tableToJSON({});//Here grab all 50 records.
window.location = "excel/Reporte_Insertados.jsp?registros="+JSON.stringify(tabla_reporte_insertados)
}
My jsp code to receive the data
<%#page import="org.json.JSONObject"%>
<%#page import="java.text.SimpleDateFormat"%>
<%#page import="java.text.DateFormat"%>
<%#page import="java.util.Date"%>
<%#page import="org.json.JSONArray"%>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<%
String datos = request.getParameter("registros");
JSONArray jsonArray_datos = new JSONArray(datos);
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition", "attachment; filename=REPORTE_CARGA_MASIVA.xls");
%>
ERROR
enter image description here
#Felipo If you need to send a json, kindly refrain from adding it to the url. The url string has a character limit.Please look at : What is apache's maximum url length? . Also, according to convention in order to send a json via the request you need to add it to the request body instead of the url. Use an ajax request to send the data to the endpoint instead of passing it via the url.
Usually i can find solution provided by StackOverflow community in older questions. This time my brain stopped working, i guess...
All I'm trying to do is show a list of customers which I'm taking out of MySQL database. Everything is going fine, but when i'm passing the List from controller to view I can't use it in jsp file, as it appears to be out of scope(?).
If you could suggest any solutions / links / tutorials i would be really thankful
CustomerDAO:
public List<Customer> getAllCustomers()
{
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("library-manager");
EntityManager entityManager = entityManagerFactory.createEntityManager();
TypedQuery<Customer> query = entityManager.createQuery("select e from Customer e", Customer.class);
List<Customer> customers = query.getResultList();
entityManager.close();
entityManagerFactory.close();
return customers;
}
CustomersController:
#RequestMapping(value = "/getAllCustomers")
public ModelAndView getAllCustomers(){
List<Customer> customers = customerDAO.getAllCustomers();
return new ModelAndView("getAllCustomers", "customersList", customers);
}
At this point I have no clue how to access this List in my jsp file (getAllCustomers.jsp).
When I try to access it in Java block <% %>, then I get simple errors like:
"customers cannot be resolved to a variable"
getAllCustomers.jsp:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%# page import="db_objects.Customer" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h2>List of all customers:</h2>
<%
for(Customer customer : customers){
out.println(customer.getCustomerFirstName);
out.println(customer.getCustomerLastName);
out.println(customer.getCustomerContactNumber);
}
%>
</body>
</html>
I hope you will find some patience to help me a little bit here :)
edit
I got some information that my question may be the same as this one
I'm not sure if it's automatic system or not, but my question is not how to use for loop but how to pass a collection to jsp via ModelAndView.
edit2
I just figured it out what #RamPrakash meant. I will try his solution tomorrow.
But until then, maybe someone from different timezone could answer if using scriptlet instead of JSTL may cause that problem?
Thanks in advance!
In your jsp you are referring to the customers list by customers. This however is only a valid identifier in the context of the getAllCustomers method of your controller.
Try customersList instead and consult the JavaDoc of the ModelAndView
This question already has an answer here:
How do I pass current item to Java method by clicking a hyperlink or button in JSP page?
(1 answer)
Closed 7 years ago.
I have a facultylist.jsp page which displays List<Faculty> as a request attribute parameter in forEach loop and I want every item in this loop to be a link to specified faculty facultyview.jsp. How can I achieve that ?
facultylist.jsp:
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculties</title>
</head>
<body>
<h1>Faculties list</h1>
<ul>
<c:forEach var="faculty" items="${faculties}">
<li>${faculty.name}</li>
</c:forEach>
</ul>
</body>
</html>
facultyview.jsp:
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculty</title>
</head>
<body>
<h1>${faculty.name}</h1>
<ul>
<li>Faculty name: <c:out value="${requestScope.name}"></c:out></li>
<li>Total seats: <c:out value="${requestScope.total_seats}"></c:out></li>
<li>Budget seats: <c:out value="${requestScope.budget_seats}"></c:out></li>
</ul>
apply for this faculty
</body>
</html>
I don't know if its may help, but I'm using following technologies: tomcat, jsp, servlets and log4j.In my project I have one FrontController, which is a servlet that interacts with Command pattern - each Command returns a path to resource and action type: forward or redirect.
You can solve your issue by adding a query params to the link, edit with respect to the comment. Note that you cannot access directly the JSP pages that reside under WEB-INF folder. Also, to encode properly the paramters, better construct url like
<c:url value="facultyview.jsp" var="url">
<c:param name="name" value="${faculty.name}"/>
<c:param name="total_seats" value="${faculty.total_seats}"/>
<c:param name="budget_seats" value="${faculty.budget_seats}"/>
</c:url>
<li>${faculty.name}</li>
and than than in your facultyview.jsp read from the query params
<li>Faculty name: ${param.name}</li>
<li>Total seats: ${param.total_seats}</li>
<li>Budget seats:${param.budget_seats}</li>
This direct JSP communication should solve your immediate issue, but a truly proper way would be to pass an id of a faculty to servlet, fetch the faculty instance, place in the model and pass to the view.
in other way is just take the selected value from the drop down with a name and forward it to front controller servlet ,there use if else conditions and depends on the value you could forward the request to corresponding jsp or servlet
<select name="value"> in jsp
String value=req.getParameter("value"); in servlet
if()
else if()
If you have a field in Faculty entity simply:
${faculty.name}
#Mark: faculty represents an entity from database, i'm not sure if I want to change it adding another field, or you mean some other way ?
Add a field does not means you must change database, you can have a Helper entity that inherits from Faculty and have more fields you can need,
public class FacultyFormHelper extends Faculty implements Serializable {
private String URL;
and in your view:
${facultyHelper.name}
But, If you don't want to modify your database, either create a helper class, you may add onclick event to the <a>
<a onclick="goToURL(${faculty.id})">
Then retrieve the data... i'm not sure how you get the urls... from a variable in the view, ajax call or wherever you have this URL...
Good day!
I encountered the following error upon running my JSP program.
java.lang.IllegalStateException: PWC3991: getOutputStream() has already been called for this response
It seems like the html file inside my JSP doesn't work.
My code is as follows:
<%#page import = "java.util.*"%>
<%#page import = "javax.servlet.*"%>
<%#page import = "javax.servlet.http.*"%>
<%#page import= "session.*" %>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
Item item = (Item) request.getAttribute("invenItem");
if (item != null) {
out.println("<html><title>Inventory Item</title>");
out.println("<body><h1>Inventory Item Details:</h1>");
out.println("Stock ID : " + item.getStockID() + "<br/>");
out.println("Name : " + item.getItemName() + "<br/>");
out.println("Unit Price: " + item.getUnitPrice() + "<br/>");
out.println("On Stock : " + item.getOnStock() + "<br/>");
out.println("</body>");
out.println("</html>");
} else {
RequestDispatcher rd = request.getRequestDispatcher("DataForm.html"); //NOT WORKING
rd.include(request, response);
out.println("<br>Item not found...<br>");
rd = request.getRequestDispatcher("ItemEntry.html"); //NOT WORKING
rd.include(request, response);
}
%>
</body>
</html>
My html Files are located inside the folder WEB-INF. How can I make it work? DO i need to import it also? Thank you.
Don't use scriptlets (those <% %> things). JSP is a template technology for HTML. You don't need all those nasty out.println() things for HTML. Just write HTML plain in JSP.
So, instead of
<%
out.println("<html><title>Inventory Item</title>");
%>
just do
<html><title>Inventory Item</title>
(note that this results in invalid HTML, there should be only one <html> tag in a HTML page and only one <title> in the <head>, but that's a different problem, the w3 HTML validator should give a lot of hints and answers, also get yourself through some HTML tutorials)
JSP offers EL (Expression Language, those ${ } things) to access backend data, i.e. the data which is present as attribute in page, request, session and application scopes. It can be accessed using the attribute name.
So, instead of
<%
Item item = (Item) request.getAttribute("invenItem");
%>
use
${invenItem}
and instead of
<%
out.println("Stock ID : " + item.getStockID() + "<br/>");
%>
use
Stock ID: ${invenItem.stockID}<br/>
JSP also offers taglibs like JSTL to control the page flow and output.
So, instead of
<%
if (item != null) {
} else {
}
%>
use
<c:choose>
<c:when test="${invenItem != null}">
</c:when>
<c:otherwise>
</c:otherwise>
</c:choose>
JSP also offers <jsp:include> tag to include page fragments.
So, instead of
<%
RequestDispatcher rd = request.getRequestDispatcher("DataForm.html"); //NOT WORKING
rd.include(request, response);
%>
use
<jsp:include page="/WEB-INF/DataForm.jsp" />
(and rename it to .jsp)
And the exception will disappear.
See also:
JSP tag info page
How to avoid Java code in JSP files?
Java web development, what skills do I need?
Unrelated to the concrete problem, almost all of the links in this answer was already (in)directly given to you in your previous questions. Take them serious. To become a great programmer (as you ever stated in a question/comment), take some time to get yourself through those links (and the links in the links).
Firstly, try to avoid putting code onto your JSP page - it violates the MVC/separation of concerns paradigm that is a central part of JSP.
Second, plain old JSP's getting a bit old - using JSF/facelets/etc is recommended these days.
As for your actual problem, I'm not totally familiar with the technique you're employing, but the exception basically means that you've tried to send content after the latest point at which your able to (generally, after sending headers). In this case, I think what's happening is that you've already started sending the current page when you ask it to send a different page.
Simplest fix I can think of: rather than trying a conditional include based on results, just redirect to a different page.
The error indicates that the error lines of code cannot be called once something has been printed out to the output stream in jsp (including even the doctype declaration)
So you can try to put those pieces of code at the top of your page.
You can not use
out.print() and Requestdispatcher simultaneously....
It means after execution of out.print() there should not be any execution of statement with requestdispatcher.forward()....
So remove out.println() form else block.
i am creating a web project using JSP, and is trying to implement a simple search for users from my database using jquery autocomplete, however i am having trouble understanding how it works. i have little to no knowledge on jquery and ajax just to let you know. i have done the following code and am stuck.
<%#page contentType="text/html" pageEncoding="UTF-8" import="ewa.dbConnect,ewa.sendEmail,ewa.pwGen,ewa.hashPw,java.sql.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<link rel="stylesheet" type="text/css" href="css/jquery.autocomplete.css" />
<script src="js/jquery.autocomplete.js"></script>
<script type="text/javascript"
src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<input type="text" id="search" name="search"/>
<script>
$("#search").autocomplete("getdata.jsp");
</script>
</body>
</html>
getdata.jsp
<%#page contentType="text/html" pageEncoding="UTF-8" import="ewa.dbConnect,java.sql.*" %>
<%! dbConnect db = new dbConnect(); %>
<%
String query = request.getParameter("q");
db.connect();
Statement stmt = db.getConnection().createStatement();
ResultSet rs = stmt.executeQuery("SELECT username FROM created_accounts WHERE username LIKE "+query);
while(rs.next())
{
out.println(rs.getString("username"));
}
db.disconnect
%>
if i am not wrong i read from a website, the parameter q is default and is just there, however how do i display the data? how do i pass the values from getdata.jsp into the autocomplete?
You're calling the autocomplete script tag before jQuery has been included. So, not having jQuery to latch onto (as the jQuery object hasn't been defined), nothing from the jQuery autocomplete plugin will load.
You have
<script src="js/jquery.autocomplete.js"></script>
<script type="text/javascript"
src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
It should be
<script type="text/javascript"
src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script src="js/jquery.autocomplete.js"></script>
Reverse the order, and the Firebug errors you mentioned should disappear; I'm not sure it'll solve everything, but nothing will work until that's resolved.
I don't see jQuery UI being included (that one provides the autocomplete functionality)
http://jqueryui.com/demos/autocomplete/
So you need to include jquery.ui.autocomplete.js
(Or are you using the plugin autocomplete? if so, move to the jquery UI version)
Could also be that the data from getdata.jsp is malformed for the use in autocomplete.
How you tried debugging the javascript in a browser such as chrome or in firefox(with firebug)
I usual give (for jquery UI autocomplete) a JSON formatted answer, while I see your answer loop give a CR delimited list.
In getdata.jsp instead of produce:
jim<cr>
jack>cr>
jhon<cr>
try to return:
[{label: 'jim', value: 'jim'}, {label:
'jack', value: 'jack'}, {label:
'jhon', value: 'jhon'}]