[SOLVED] Does not redirect properly - Java Discussion Boards

Gabor Patch Generator

amirsharifzadeh20-Dec-14 22:01

amirsharifzadeh

20-Dec-14 22:01

I found the answer.

modified 21-Dec-14 22:26pm.

Re: Gabor Patch Generator

Richard MacCutchan20-Dec-14 22:14

Richard MacCutchan

20-Dec-14 22:14

Please read http://www.codeproject.com/Messages/3137511/Forum-Guidelines-PLEASE-READ.aspx[^].

How to Use Delimiters in my program(Does not work and Crashes)

Kaytlyn Grace Lau20-Dec-14 7:44

Kaytlyn Grace Lau

20-Dec-14 7:44

Hello, I am doing a project for school and I cannot figure out what is wrong.

int AB = 450;
    int BC = 140;
    int CD = 120;
    int DE = 320;
    int EF = 250;
    int FG = 80;
    String Place1, Place2, Place3, Place4, Place5, Place6, Place7, Place8, Place9, Place10;
    double MPG;
    double MPH;
    double Gallon;
    String Trip1;
    double Hour1;
    int Minute1;
    double Money1;
    int Dist1;
    String String;
    Scanner scan = new Scanner(new File("C:\\Users\\Evelyn\\workspace\\ACSL\\src\\testimput"));
    NumberFormat numfmt = NumberFormat.getCurrencyInstance();
    NumberFormat decfmt = new DecimalFormat("00");
    String delims = "[ ]+[,]";
    MPG = scan.nextDouble();
    Gallon = scan.nextDouble();
    MPH = scan.nextDouble();

    Place1 = scan.next();
    Place2 = scan.next();
    Place3 = scan.next();
    Place4 = scan.next();
    Place5 = scan.next();
    Place6 = scan.next();
    Place7 = scan.next();
    Place8 = scan.next();
    Place9 = scan.next();
    Place10 = scan.next();

For the program, there is a textfile that contains exactly:

Quote:
25, 3.79, 50
A, C
E, F
C, G
B, E
A, G

However, when I attempt to run it crashes.

Exception in thread "main" java.util.InputMismatchException
	at java.util.Scanner.throwFor(Unknown Source)
	at java.util.Scanner.next(Unknown Source)
	at java.util.Scanner.nextDouble(Unknown Source)
	at Prog_2014.main(Prog_2014.java:34)

Does anyone know how to fix this? What am I doing wrong and what must I add.

Re: How to Use Delimiters in my program(Does not work and Crashes)

Richard MacCutchan20-Dec-14 21:06

Richard MacCutchan

20-Dec-14 21:06

You have not set the comma as a delimiter in your scanner, so it is reading it as a part of the next field.

Re: How to Use Delimiters in my program(Does not work and Crashes)

Richard MacCutchan21-Dec-14 4:01

Richard MacCutchan

21-Dec-14 4:01

Try adding the following line before the first call to nextDouble.

Java

scan.useDelimiter("\\s*[,\\s*]\\s*");

modified 21-Dec-14 10:23am.

Re: How to Use Delimiters in my program(Does not work and Crashes)(SOLVED)

Kaytlyn Grace Lau21-Dec-14 9:18

Kaytlyn Grace Lau

21-Dec-14 9:18

Thank you so much! That's very useful. Would you mind explaining the logic and how that statement works so I will be able to do it in the future?

Re: How to Use Delimiters in my program(Does not work and Crashes)(SOLVED)

Richard MacCutchan21-Dec-14 22:44

Richard MacCutchan

21-Dec-14 22:44

Firstly, if you create a delimiter string (as you did in your code) you still need to apply it to the scanner so that the scanner applies it to every line it reads. The default for the scanner is to ignore all whitespace characters (as described in http://docs.oracle.com/javase/7/docs/api/java/lang/Character.html#isWhitespace(char)[^]). If that does not control the input data that you are working with then you need to set a custom delimiter, which can be a simple string of characters, or a regular expression pattern, as described in http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html[^].

The pattern I suggested ("\\s*[,\\s*]\\s*") breaks down as follows:

Actual pattern is: \s*[,\s*]\s*

\s*     : 0 or more whitespace characters (e.g. spaces, tabs etc)
[,\s*]  : a comma or 0 or more whitespace characters
\s*     : 0 or more whitespace characters (e.g. spaces, tabs etc)

I'm not an expert in RegEx patterns so I am sure this can be improved upon. But what you have in your input file is:

25.0, 37.1, 10

So the the basic pattern is:

0 or more whitespace characters
0 or more comma characters
0 or more whitespace characters
a number
0 or more whitespace characters

[SOLVED] Does not redirect properly

Django_Untaken14-Dec-14 20:52

Django_Untaken

14-Dec-14 20:52

Hello. I am trying to authenticate input from databse using JDBC and then redirect the user to another page accordingly. Here is my code for small servlet that does authentication

Java

public class ServletAuthUser extends HttpServlet
{
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
	{
	  try
	  {
		String sUserName = request.getParameter("username");
		String sPassword = request.getParameter("password");

		String sURL = "Jdbc:Odbc:ServletsDB_DSN";
		String sForName = "sun.jdbc.odbc.JdbcOdbcDriver";
		MyDatabase db = new MyDatabase(sURL, sForName);		
			
		boolean bIsUserValid = (sUserName.equals("admin") && sPassword.equals("admin")) ? true : false;//boolean bIsUserValid = db.AuthUser(sUserName, sPassword);
		db.CloseConnection();
			
		if(bIsUserValid == true)
        		response.sendRedirect("welcome.html");
		else
			response.sendRedirect("error.html");
}

And here is my welcome page.

HTML

<html>
	<head>
		<title>Welcome</title>
	</head>
	<body>
		<h1>Welcome ADMIN.</h1>
	</body>
</html>

I have tried recompiling the servlets and then restarted the apache server several times but my login servlets still shows me the old output that I tried little ago (another servlet which generates data using JDBC). Why is it still showing the same old output despite recompiling the servlet and restarting the server? Please ask for any info if you need. Thanks for any input.

EDIT
I was not writing the deployment descriptor properly.

modified 19-Dec-14 14:13pm.

Re: Does not redirect properly

Richard MacCutchan14-Dec-14 22:19

Richard MacCutchan

14-Dec-14 22:19

Are you sure that you have copied the new servlet to the server correctly?

JayantiSh13-Dec-14 12:08

JayantiSh

13-Dec-14 12:08

Hello friends,
I am new to Java having understanding of the basics. But, I have given a mini project to make the Login Frame on the eclipse platform and to verify the user login details and thereby showing his access rights on the other frame. I have to use Derby database for it.
I am really confused Frown | :(

as I have to submit it in next 3 days Cry | :((

It would be kind if anyone can help me.
Thanks

Re: Login Details Authentication

Richard MacCutchan13-Dec-14 21:33

Richard MacCutchan

13-Dec-14 21:33

It is unlikely that any response in this forum would be enough to help you, if you don't understand how to create a simple application such as you describe. For a start you will need to design your database and learn how to access it in Java; take a look at http://docs.oracle.com/javase/tutorial/jdbc/index.html[^]. As for the login screen, that is just a matter of adding a few labels, text boxes and buttons to a JFrame and accessing the information provided by the user. There are many useful samples in http://www.codeproject.com/KB/java/[^].

Re: Login Details Authentication

JayantiSh16-Dec-14 3:27

JayantiSh

16-Dec-14 3:27

thnks Richard Smile | :)

Re: Login Details Authentication

TorstenH.17-Dec-14 2:19

TorstenH.

17-Dec-14 2:19

What have you achieved so far?

The Eclipse IDE is a Eclipse RCP Application.
You can easily exchange the original login and build your thingy as a Eclipse RCP Plugin.

Lars Vogel has a lot of really good tutorials for you:
http://www.vogella.com/tutorials/EclipseRCP/article.html[^]

regards Torsten
I never finish anyth...

java

Member 109275319-Dec-14 1:48

Member 10927531

9-Dec-14 1:48

what is interface ?and why it is used?

Re: java

Richard MacCutchan9-Dec-14 6:11

Richard MacCutchan

9-Dec-14 6:11

You can find the answer quite easily by looking at any online documentation, that Google will find for you, See http://www.codeproject.com/Messages/3137511/Forum-Guidelines-PLEASE-READ.aspx[^].

Re: java

TorstenH.11-Dec-14 22:14

TorstenH.

11-Dec-14 22:14

The Java Tutorial - What Is an Interface?[^]

regards Torsten
I never finish anyth...

Passing JTextField Values to MouseListener Interface

Django_Untaken2-Dec-14 3:37

Django_Untaken

2-Dec-14 3:37

Hello. I am implementing action event in a class 1, database handling in class 2 while all the controls are instantiated in a 3rd class. Heirarchy becomes like this.

Java

// class for interacting with the database
class MyDatabase
{
  // add, update and delete functions here
}

// class for handling events
class ActionHandler implements ActionListener
{
  MyDatabase db = null;
  View m_View = null;

  public ActionHandler(View view)
  {
    m_View = view;
    db = new MyDatabase();    
  }
  public void actionPerformed(ActionEvent ae){
    if(ae.getSource() == MyView.AddButton) // HOW DI I GET VALUES HERE ???
      db.AddRecord();
  }
}

// class for making simple GUI for 3 JTextFields and 3 JButtons (add, update, delete)
class View
{
  ActionHandler action_handler = null;
  public View()
  {
    action_handler = new ActionHandler(this);
    // all the controls are created in this constructor.
    
    AddButton.addActionListener(action_handler);
  }
}

Question is: how do I pass my JTextField values from View class to ActionHandler class ? I don't think passing these values in the constructor of ActionHandler is good idea.

Re: Passing JTextField Values to MouseListener Interface

Richard MacCutchan2-Dec-14 5:27

Richard MacCutchan

2-Dec-14 5:27

You have a reference to the View object in your ActionHandler so you can access the view's properties and methods from there. Although I am not sure where MyView.AddButton fits in with the rest of your code.

Re: Passing JTextField Values to MouseListener Interface

Django_Untaken3-Dec-14 5:52

Django_Untaken

3-Dec-14 5:52

YESSS. Thanks. One more question: along with View class object if I pass an object of MyDatabase in ActionListener constrcutor as well...like this

Java

class ActionListenderHandler implements ActionListener
{
  MyDatabse MyDB = null; View myView;
  public ActionListenerHandler(View view, MyDatabase db)
  {
    myView = view;
    MyDB = db;
  }
}
class View
{
  MyDatabase db = null;
  public View()
  {
    db = new MyDatabase("..."); 
    actionListener = new ActionListenerHandler(this, db)

    //.....
    db.CloseConnection();
  }
}

After calling db.CloseConnection in View class, do I have to call myDB.CloseConnection in ActionListener class explicitly ? Thanks

Re: Passing JTextField Values to MouseListener Interface

Richard MacCutchan3-Dec-14 6:26

Richard MacCutchan

3-Dec-14 6:26

No, because MyDB in the ActionListenderHandler and db in the View, both refer to the same object, just by different names, as shown by the line of code:

Java

MyDB = db;

Authentication and Encryption

Anele Ngqandu2-Dec-14 2:26

Anele Ngqandu

2-Dec-14 2:26

Hello

I am experimenting with java, I need a tutorial that will help me with creating rights,since different roles will not have access to same areas of the application.
Also what is the best way to encrypt passwords?

Looking forward to your replies.
Thanks Thumbs Up | :thumbsup:

Act as though it were impossible to fail

Re: Authentication and Encryption

Richard Deeming2-Dec-14 2:38

Richard Deeming

2-Dec-14 2:38

Anele Ngqandu wrote:
Also what is the best way to encrypt passwords?

You don't - you store a salted hash of the password.
Salted Password Hashing - Doing it Right[^]

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Authentication and Encryption

Anele Ngqandu2-Dec-14 2:44

Anele Ngqandu

2-Dec-14 2:44

Thank you Sir

Act as though it were impossible to fail

Re: Authentication and Encryption

ZurdoDev2-Dec-14 2:41

ZurdoDev

2-Dec-14 2:41

Anele Ngqandu wrote:
Also what is the best way to encrypt passwords?

Just google for examples of encryption in java and you should find lots of examples.

Also, it is recommended that a password be hashed, as Richard mentions, and then store the hash but there are times where encryption is needed.

There are only 10 types of people in the world, those who understand binary and those who don't.

Re: Authentication and Encryption

Anele Ngqandu2-Dec-14 2:45

Anele Ngqandu

2-Dec-14 2:45

Act as though it were impossible to fail

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.