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Where is your import on .jsp page?
Should be
<%@page import="<PackageName>.DatabseDAO" %>
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I found the answer.
modified 21-Dec-14 22:26pm.
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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.
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You have not set the comma as a delimiter in your scanner, so it is reading it as a part of the next field.
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Try adding the following line before the first call to nextDouble.
scan.useDelimiter("\\s*[,\\s*]\\s*");
modified 21-Dec-14 10:23am.
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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?
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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
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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
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;
db.CloseConnection();
if(bIsUserValid == true)
response.sendRedirect("welcome.html");
else
response.sendRedirect("error.html");
}
And here is my welcome page.
<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.
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Are you sure that you have copied the new servlet to the server correctly?
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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  as I have to submit it in next 3 days 
It would be kind if anyone can help me.
Thanks
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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/[^].
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thnks Richard 
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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...
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what is interface ?and why it is used?
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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.
class MyDatabase
{
}
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)
db.AddRecord();
}
}
class View
{
ActionHandler action_handler = null;
public View()
{
action_handler = new ActionHandler(this);
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.
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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.
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YESSS. Thanks. One more question: along with View class object if I pass an object of MyDatabase in ActionListener constrcutor as well...like this
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
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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:
MyDB = db;
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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
Act as though it were impossible to fail
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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
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Thank you Sir
Act as though it were impossible to fail
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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.
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