I have used jsp's to passing request to the servlet or controllers. but we can also pass request from javascript using ajax and sending data using json.
what is the good approach and why? or does it depends on the situations? is yes, what kind of situations?
I am working on an independent project it is a simple little text based rpg that will run in a counsel window. I have an object for Character that is creating during a CreateCharacter method. I want the play to be able to enter a character that will open up a menu that displays things like the name and health and stuff of the character from the object created in CreateCharacter, but because I have it in a different class I don't know how to reference the object made in CreateCharacter.
I have it in 6 files
Character --- Object with getters/setters for things like name, age, race, class, ect MainMenu --- Displays title and promts for new game and quit CreateCharacter --- Walks through and sets all values in Character Stats --- Keeps the players stats (health, attack, ect) in an array Intro --- Beginning demo thing (not really important for this question) Menu --- Displays all current user stats (Having issues with this one)
When I hit the url at the first time my call goes to the spring controller and sets the userDetails objects in the modelAndView.addObject("userDetails", userDetails.getUserDetails()) and returns the userDetails.html page. if I click any link in the same page i want to pass same (userDetails) object thru javascript or jquery and calls the another(controller) method and returns the same (userDetails.html) page.
It means how can I pass the java object thru javascript or jquery and calls the controller. If I get the same object in my controller i can avoid calling the db again.
I am trying to pass an object of type Product p to my editProduct method, however trying to call p.getName(); doesn't work and throws a NullPointerException. The same kind of thing works for my displayRecord method (in a different class) and I can call .getName() on Product p, also passed as an argument to that method. Below is my editProduct class. The NullPointerExcepion is being thrown at line 61 (i.e., nameField.setText(p.getName());).
I don't know if I explained right, so here's a line thing of how the classes relate:
And as a side note: adding the line p = new Product(); fixes it and successfully runs the class (including the Save and Quit parts) but obviously I want it to specifically refer to the Product I pass to the method.
I'm asking a question because I don't understand how Product p could possibly be null, because the argument is passed through my DisplayRecord class, which also takes a Product p argument and works. In that class, I have declared Product prod = p; and prod is what I am passing to editProduct.
I am new to JSTL and JSP & I am running 2 seperate SQL queries from a java/jsp program and I need to display the results from both queries on one JSP page output.Currently I have java code that passes the 2 queries to a method along with passing the jsp files to output the query results
- the method dispatches the results to these 2 JSP pages using JSTL tags in hope for separate output results:
I need to have a way to display these 2 outputs into 1 jsp page: - currently one just overwrites the other.I also tried using the jstl core <c: tags in 2 separate methods on the same jsp page but the <c: tags just resulted in overwriting one another - The queries run and display fine except I cannot get them both to display correctly.using jstl and jsp for displaying multiple queries on the same page.example: the jsp file that runs the queries:
I want to validate the user session everyone when ever the request comes for any jsp page. I am able to validate the user in a filter for the first time. But i am confused what would happen when the request comes for other pages...how will i be able to get the same session from the server?
I have index.jsp in that page logout is available. while hitting the button . i want to invalidate all the session variable which i used. but it is not happening.
I'm new to JSP but I've to use it to grab data coming from an external site, pass data to a Bean, write data in a DB and redirect the user to another page. Follow the JSP page.
<%@page import="EJB.getResponse"%> <% long paymentID = Long.parseLong(request.getParameter("paymentid")); String responsecode = "9999"; getResponse g = new getResponse();
[Code] ....
This is the bean:
@ManagedBean @RequestScoped public class getResponse implements Serializable { private Long paymentId; private String result; private String auth;
[Code] ....
On the console I see the prints but I receive the NullPointerException
WARNING: StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception java.lang.NullPointerException at EJB.getResponse.printData(getResponse.java:72) at org.apache.jsp.notify_jsp._jspService(notify_jsp.java from :60) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
Basically I am making a paddleball game, like i'm sure everyone does in learning Java. I'm supposed to use different classes for each component, i.e. one for the ball, one for the paddle, and one for the display, then finally one as a 'controller' to implement mouselistener and stuff.
However, I can't quite grasp how to implement the paintComponent method. I know I can only have it in one class extended from JPanel, and I have the syntax for creating an object which I understand is something like this:
public void paintComponent(Graphics g){ //this is the rectangle my game will be played on, super.paintComponent(g); //a gray background to define boundaries for the ball g.setColor(Color.GRAY); g.drawRect(0, 0, Frame.getHeight(), Frame.getWidth());
However what I don't understand is, how do I then pass this graphics object to the ball and paddle to let them draw themselves? I found something that described it like this here
What I don't get is, if I use this, where would I put the drawRect and stuff to make the other shapes I need? in their class, under the entity.Draw(g) method? or in the display class where it calls the graphic object in the first place?
Last, how can I have my controller class refresh the displays of each of these with the timer I have implemented? Is there a simple way to call one refresh command and have it refresh the drawing of both the paddle and ball simultaneously, or would I need to call a separate refresh command for each object?
combo is the private CombinationLocker object I created within the Locker class. Do I need to pass the combo object on to the CombinationLock class? For reason, I do not comprehend, the combination password from the main class is not passing through to the CombinationLock class, and the combination values are all zero.
How to use the id parameter in my documents entity to download documents from a list of documents. Normally I use ListDataModel and the getRowData method. I would like to know how to achieve the same thing using an ordinary List object.
My list of documents is called List<CountryDocs> selectedDocs;
Clicking on the download link calls the following method in my managed bean:
@ManagedBean(name = "countryDocBean") @SessionScoped public class CountryDocBean { private List<CountryDocs> selectedDocs; public StreamedContent getDownloadedFile() {
[Code] ....
Debugging shows the value for the id is 0 and this results in a NullPointerException. I've tried several methods for grabbing the document id in my backing bean, but no luck yet. I also read about the the ViewParams and ViewAction method but they caused validation errors to do with the <f:metadata> tags. I don't know how to obtain this value using a normal List object.
I know that there are 9 implicit objects that are available in a JSP page , except the page implicit object every object has certain utility ,but i am not able to understand the usage of a 'page' implicit object.
I've read it is actually an object of the servlet which is obtained after compiling this JSP page ,moreover a reference of Object class hold this 'page' object so there are only those 11 legacy methods of Object class which anyone can invoke on it and even if the 'page' object is typecasted to our generated servlet class it will also be of no use until there are any instance methods or fields(which are not Thread-safe) declared through <jsp:declaration> tag ,and writing instance method through jsp:declaration will again bring us to the old discussion of avoiding java code from JSPs..
public Polygon polygonFrom(Point[] corners) { // method body goes here }
So from what I understand this is a constructor method for a Polygon object from the Polygon class. What I dont get is the name of the method polygonFrom()
Shouldn't a constructor for a Polygon just have the same name as the class? Because from earlier examples in the tutorial it seems to me that this is what has been done
For example:
public Bicycle(int startCadence, int startSpeed, int startGear) { gear = startGear; cadence = startCadence; speed = startSpeed; }
Java SE Runtime Environment build 1.8.0..This is part of the code:
public static int addAddress (String[] number, boolean[] front, double[] total) { int num = 0; double ffee = 0; /*boolean value = false;*/
[code]...
I have tried using the line of code commented out, /*boolean value = false;*/. However, another error is displayed. The compiler shows the following...
Inspection.java:33: error: incompatible types: boolean cannot be converted to boolean[] front[num]= defineFront(num, value); ^ Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output error...I know that boolean values are by default stored as false, once you create the array. However, I'm having trouble passing the variable to the method.
I got the correct output here. But now I want to generalize my method into a utility class so that I can reuse the same method for setting response data directly to respective beans as given below:-
My question is how will I pass the bean object in my utility class?
public static Object getResponseData(String response,[b]String bean[/b]) throws Exception { ObjectMapper mapper = new ObjectMapper(); mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false); JsonNode root = mapper.readTree(response);