JSP :: Accessing ServletConfig Initialization Parameters
May 12, 2014
I am trying a simple program to access ServletConfig initialization parameter in a jsp. But I am not clear how its working. This is web.xml
<web-app>
<servlet>
<servlet-name>Myservlet</servlet-name>
<jsp-file>/JjspInit.jsp</jsp-file>
<init-param>
<param-name>para</param-name>
<param-value>valu</param-value>
[Code] ....
Now If I hit /Allen it sets init parameter for both servlet MyServlet and jsp JjspInit. I don`t have any servlet all I have is a web.xml and a jsp page. But accessing JjspInit.jsp directly gives null.
How hiting the url /Allen prints valu. This code is on JjspInit.jsp .
So does that mean that in web.xml I have registered this jsp as the target for /Allen. And one more question directly accessing the jsp page shows null it means init parameter haven`t been set.
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Jan 24, 2015
I need to implement a URL which looks something like below one. The Notable thing is that its only one parameter i need to access and the value that's supposed to be held by the parameter is encrypted which may contains characters like & and =.
Example 1.
www.abc.com/disp?v=qww78agd=
The parameter v in above url contains value qww78agd=.
Supposing the encryption turns out the following way.
Example 2.
www.abc.com/disp?v=qww7&f=iuy68=
www.abc.com/disp?v=qww7&f==iuy68=
Then servlet will take v and f as two separate parameters, whereas i want to obatain qww7&f==iuy68= from parameter.I thought of taking up all key value pairs from request HashMap and concatenating the joints via & and =. But the problem is that two consecutive = signs as in second case of example 2, its treated as only one equal to in request key,value map. Hence, my other = sign(s) are lost.Is there any way such that i can get query string part as it is on my servlet and parse it using string processing on my own?
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Dec 20, 2014
I come from a C++ background and I recently started learning Java from "Thinking in Java" 4th Edition by Bruce Eckel.What's the difference between:
// explicit in class initialization
// saw this on page 126
class A {
}
public class B {
A obj1 = new A();
A obj2 = new A();
}
and
// non static instance initialization
// saw this on page 132
class A {
}
public class B {
A obj1;
A obj2;
{
obj1 = new A();
obj2 = new A();
}
}
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Apr 29, 2014
I am trying to make a game, for some reason i have begun to get a java.lang.StackOverflowError.
I am not exactly sure how i can fix it. only removing line 14 from infopannel1 (and everything that used that class.) seems to work. im not sure what else i can do to fix it. or why its resulting in stack overflow for that matter.
I am putting in a link for the files i wrote this using bluej (several classes have no relevance, errorv2, demonstration, folderreadertest, ReadWithScanner, saveloadtest, menutest,rannum, and menutestTester. are all irrelivent to my problem.)
[URL] .....
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Sep 17, 2014
I came across this code which proves that variable initialisation occurs before even constructors are called.However, I am confused over some things.
Firstly, from my understanding, when a new House object is created in this line House h = new House(); , the no-arg constructor of the House class is called.
Since the no-arg constructor House() is called, why are all the creation of Window objects being run first ? Shouldn't Java jump straight into the no-arg constructor House() ?
class Window {
Window(int marker) { System.out.println("Window(" + marker + ")"); }
}
class House {
Window w1 = new Window(1); // Before constructor
House() {
// Show that we’re in the constructor:
System.out.println("House()");
w3 = new Window(33); // Reinitialize w3
[code]...
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May 12, 2014
I am using netbeans 7.2, glassfish 3.1.2, JSF 2.1 and Primefaces 3.2. When I add more than three menu tabs, I get this error ui layout initialization error the center-pane element does not exist the center-pane is a required element. This is my template.xhtml code:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui">
[Code] ....
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Sep 9, 2014
public class SavingsAccount extends Account {
private static final double MIN_BALANCE = 100.00;
private static final double RATE = 0.035;
public SavingsAccount(Customer customer, double bal, String accountNum,
Transaction[] trans) {
super(customer, bal, accountNum, trans);
[code]....
When I execute this code there is an error in Transaction array initialization. Change the Saving account constructor from (String customer,double balance, String accountnumber,Transaction[] tr) to (String customer,double balance, String accountnumber,Transaction tr)
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Apr 2, 2015
What static initialization blocks do in java?
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Mar 20, 2015
I have a question related to q44 of Examlab.
public static void main(String... args) {
String i;
// String i = null; that would compile
if (i == null) {// this line does not compile as i was not initialized
System.out.print("A");
} else {
System.out.print("B");
i = "A";
main("A", "B");
}
}
Why does the above code not compile although the statement String i should lead to an initialisation of i to the value of null which is the default value for Strings.
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Feb 20, 2014
I remember reading Instance variables & local variables (in methods) are initialized to appropriate value by the compiler.
Is this true for static class variables and variables in nested classes ?
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Aug 15, 2014
if, instead of an ArrayList, can I do the following to initialize a Dyanmic array ? :
First, in my class, I have :
class Example{
private int rows;
private int columns;
private AnotherClass[][] 2DArray;
public Example(int rows, int columns){
this.rows = rows;
this.columns = columns;
[code]....
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Jan 13, 2015
I want to initialize my servlet based on the scope of my application.
For example, I have multiple admins with their respective email address.
I want to perform action within my servlet based on the given environment.
Would this be the right approach, if I set the admin email addresses in my web.xml as init-param:
<servlet>
<servlet-name>ServletName</servlet-name>
<servlet-class>com.mkyong.ServletDemo</servlet-class>
<init-param>
<param-name>admin1</param-name>
[Code] .....
Now if I am in the admin 1 environment, I would initialize my servlet with request parameter admin=1 and the servlet should load email address of admin 1 and similarly when in the environment 2, should load the servlet with admin 2.
call environment 1:
/servlet/Demo?admin=1
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException{
[Code] .....
I could do the same by putting the email address of the respective admin as request param value, but i don't want to the email address to appear in the url.
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Feb 11, 2014
if I declare
class Example
{
int x=10;
......
}
It is not showing any error but when I declare
class Example
{
int x;
x=10;
............
}
it showing compile time error ....
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Feb 18, 2014
int[][] array1 = {{1, 2, 3}, {}, {1, 2,3, 4, 5}};
it initializes 3 one dimentional array:
1 - {1, 2, 3}
2 - {}
3 - {1, 2,3, 4, 5}
but it only declares two dimensional arrays.
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May 11, 2014
consider:
class A {
final Object b;
public A(C c) {
try {
b = c.someMethodThatMayThrowSomeException();
} catch (SomeException e) {
b = null; // This line results in compiler error: "variable b might already have been assigned"
}
} // take away b=null line and you get "variable b might not have been initialized" on this line
}
Why? How could 'b' be assigned if the exception was thrown?
Btw, the workaround is to wrap the method call:
private final Object initB() {
try {
return c.someMethodThatMayThrowSomeException();
} catch (SomeException e) {
return null;
}
}
and use b = initB(); in the constructor. But that seems like it should be unnecessary.
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Nov 21, 2014
public class HashMapTest {
private static HashMap mp;
public static void main(String[] args) {
// TODO Auto-generated method stub
mp=new HashMap<String, String>();
}
}
This is My Code if I create Object in two place
1)Outside main() method but within class.
2)Inside main() method like above
Will these two approach makes any difference ?
I am asking a general senerio for creating any Type of Objects Primitives or References?
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Jan 29, 2015
I know that I can declare and initialize an member variable inside a class in a single statement but I can't do them on separate sentence. Why?
For example, I am allowed to do the following,
class A{
int a = 5;
// rest of the class
}
But I am not allowed to do this,
class A{
int a;
a = 5; // it doesn't compile even when the variable 'a' is static
// rest of the class
}
Why java don't allow me to do that?
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Jan 14, 2015
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package vecchiogiovane;
import java.io.*;
public class Vecchiogiovane {
/**
* @param args the command line arguments
*/
public static void main(String[] args) throws Exception{
[Code] .....
run:
run:
ins first name:
aldo
ins first age:
35
ins second name:
[Code] ....
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Apr 21, 2015
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package BaiVeNha;
import java.util.ArrayList;
import java.util.List;
import javax.swing.table.DefaultTableModel;
[Code] ....
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May 21, 2014
I've been trying to finish this blackjack program I have been making for my programming class, however, there are a few bugs I can't seem to iron out. It's a pretty short program, it's just that I'm an idiot and can't figure basic stuff like this out. Specifically, when I try and run it, I get this error:
Error occurred during initialization of VM
java.lang.OutOfMemoryError: unable to create new native thread
Java Code:
import static java.lang.System.*;
import java.applet.Applet;
import java.util.Scanner;
import java.io.*;
import java.util.Random;
import java.util.Date;
[Code] .....
So, obviously I'm doing something horribly wrong.
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Feb 7, 2015
I am passing input from the user to a method that will initialize an array of the data (scores in this case). The method is filling the entire array with the last input value.
array initializer method
Java Code:
public static float[] inputAllScores(float validScore) {
float[] diverScores = new float[7];
for (int i = 0; i < diverScores.length; i++) {
diverScores[i] = validScore;
}
return diverScores;
} mh_sh_highlight_all('java');
[Code] .....
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Aug 25, 2014
i would like from my bean to redirect after an operation is completed to the page faces/test.xhtml?id=2? Is there a way to do this?
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Dec 7, 2014
I have GameConsole class with gamePlay(). There are two objects in this class that I want to access from a class in another package.
package blackjackControls;
public class GameConsole {
Player dealer; //both of these objects I am trying to bring over into the blackjackGUI package
Deck playingDeck;
public void gamePlay(){
[code].....
The dealer and playingDeck objects are giving me an error of unresolved. the way it is written I also get a static error on line 37. I know that I have not yet written in the actionEvent statement in the button constructor.
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Oct 19, 2014
What I want to do is this, this is my first class:
public class Footballer {
int goals;
String surname= "";
String team="";
private static int counter=0;
private int dres;
}
(this is just the header of the class... And this is my second class, which contains an ArrayList of the first class:
public class FootballTeam{
String teamname="";
String league="";
ArrayList<Footballer> f;
}
And this is my third class which contains an ArrayList of the second class:
public class FootballLeague{
String leaguename="";
ArrayList<FootballTeam> ft;
}
What I want to do is, know how many of footballers are there in the league? Meaning how many of "f"s are in the "ft"... I remember from C++ it was easy, you just did it something like this: ft.f[i]; (where i is a position), then you'd go through each of them, if you wanted to do something with them, or just ask for it's length, if you needed to know how much footballers are there.
I'm trying this method to get the size of the array in the 2nd class, from the 3rd class (containing an ArrayList of classes of 2nd class, but no luck:
int counter=0;
for(int i=0;i<this.ft.size();i++) {
counter+=this.ft[i].f.size();
}
I'm getting this: Array required, but ArrayList<FootballTeam> found ---
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Feb 18, 2015
I've created a method to calculate the ratio of one vowel to another, but I was hoping to get some feedback on another way I could approach the problem. The first bit of code is to find the vowels and assign them to an array ( for me, it seemed the easier thing to do in order to easily access the data). In the other bit of code, I have a method with two arguments (the vowels) to calculate the ratio.
public void findVowels(StringBuilder message, String delimiter) {
subString = message.toString().toLowerCase().split(delimiter);
vowelCounter = new int[5][subString.length];
// Remove all whitespace
for (int index = 0; index < subString.length; index++) {
subString[index] = subString[index].replaceAll("s", "");
[code]....
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May 14, 2014
I do not think this is possible, but I'd like to confirm. If I have an HTML page that has an embedded Java applet, and that applet in turn renders an HTML document (within the applet window), is the HTML *within* the applet part of / accessible through the DOM for the parent page?
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