JSP :: Can't Get Local Variable Value In Value Attribute Of Input Tag
Feb 3, 2014
Here, I have just tried out to take a value from the database and storing it into local variable then I want to have that value in the value attribute of <input> tag but somehow, I can't get it..
Here, below is my code..
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "[URL]....">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () { int [] myInt; // A local, member variable (because "static" keyword is not there) declared } mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
I am reading input from a file that has following information:
line 1 = numbers of integers in array, line 2 = elements in array1, line 3 = elements in array2.
These lines constitute a test case. There are 1000 test cases in the input file.
So basically, I read the length of arrays, populate the arrays by reading from the file.
The code is below ( I have not included reading input code):
while(test_case<1000){ if (count == 1){ //count keeps track of lines in input file vec_length = Integer.parseInt (tokenizer.nextToken()); count++; continue; } if (count == 2){ //populates array1 vector1 = new int[vec_length]; for (int i = 0; i < vector1.length; i++) vector1[i] = Integer.parseInt (tokenizer.nextToken()); count++; continue; }
Array2 is populated using the same as above code. However when I use the following code:
for (int i=0; i<vec_length; i++) temp += vector1[i]*vector2[i];
I get " local variable vector1 and vector2 have not been initialized error". But both arrays have been initialized in the if{} block. Is it because initialization was local to if block?
As a studyproject I'm currently writing a class the allows me to get al fun dates (like when eastern is in a given year, what day a given date has, calculate the date of tomorrow).
While working on the following method:
public String getNextDate (int day, int month, int year) { String nextDate; int nextDay = getNextDay(day, month, year); int nextMonth = getNextMonth (day, month, year); int nextYear = getNextYear (day, month, year); return nextDate = "the day after " + month +"-" + day + "-" + year + " is " + nextMonth + "-" + nextDay + "-" + nextYear + "."; }
I get a notion in my lovely IDE (eclipse) reminding me I'm not using nextDate ("The value of the local variable nextDate is not used"). But I feel I really do use nextDay here. So either I'm making a coding(style) mistake giving me this notion or I should just ignore this notion.
I have a question regarding best practice in using local variables as my method return variable. I have a method like this:
myReturnObject getMyObject(String input) { myReturnObject myObject = null; try { myObject = helperObject.someOtherMethod().getObject(input); //getObject has return type myReturnObject } catch (Exception e) { //log any problems } return myObject; }
And I'm wondering if I rewrite like this if I'll see some performance optimization benefit:
myReturnObject getMyObject(String input) { try { return helperObject.someOtherMethod().getObject(input); //getObject has return type myReturnObject } catch (Exception e) { //log any problems } return null; }
myObject can be quite large -- so I'm wondering if I can omit the myReturnObject local variable instance if it'll save some work from the garbage collector.
Okay, so I know how to get user input and create a variable from the input, create a basic addition sum etc...
So I have this code:
package calc; import java.util.Scanner; class calc{ private static final double add = 0; private static final double subtract = 0; public static void main(String args[]){
[Code] .....
I'm basically trying to make it so that when the user enters tnum, tnum2, tnum3 and tnum4, their answer turns to the variable which has to be either true or false to make the boolean work. I don't know really how to do this. I want to make it so that if they enter yes, then that makes the boolean true and the numbers will multiply and create the answer variable. If they enter no then the boolean is false and it moves onto the next if statement. How can I do this?
I need the user to be able to input a number, and for the program to assign this value to an 'int' variable. I know how to do this with a 'string' variable:
Java Code:
String options = JOptionPane.showInputDialog(null, "In your decision, how many options do you have? " +" (NOTE: The maximum number of options = 5, and you must enter your answer as a numeral.)"); mh_sh_highlight_all('java');
But I need to know how to do this with an 'int' variable.
I am trying to make a program that calculates the change due in dollars and cents. The user inputs both the amount due and the amount tendered. My program only works with whole numbers?
so i'm following a java tutorial from the book and it has a few challenge questions. and i'm stucked on one. i think i just don't understand what is it that its asking me. heres the question, Write a statement that reads a user's input integer into the defined variable, and a second statement that prints the integer. assuming scanner is given, and i checked my heading code is ok.
Scanner scnr = new Scanner(System.in); int userNum = 0; System.out.println("What is the product of 8 time 2"); userNum = scnr.nextInt();
My project in eclipse..I get the error below when I run MyTagUser.jsp -
HTTP Status 500 - /jsp/MyTagUser.jsp(14,0) Attribute subTitle invalid for tag Header according to TLD org.apache.jasper.JasperException: /jsp/MyTagUser.jsp(14,0) Attribute subTitle invalid for tag Header according to TLD org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40) org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)...et
I've already tested with disabled="false", too, but only the Session attribute is saved as NULL, though it appears in the form field. The other fields are saved properly.
int length = Integer.parseInt(spec.getAttribute("maxLength")); [5/13/14 14:52:19:497 CDT] 00000028 SystemErr R java.lang.NumberFormatException: For input string: "" [5/13/14 14:52:19:497 CDT] 00000028 SystemErr R at java.lang.NumberFormatException.forInputString(Num berFormatException.java:63) [5/13/14 14:52:19:497 CDT] 00000028 SystemErr R at java.lang.Integer.parseInt(Integer.java:502) [5/13/14 14:52:19:497 CDT] 00000028 SystemErr R at java.lang.Integer.parseInt(Integer.java:531)
Jan 11, 2015 10:08:23 PM org.apache.catalina.session.StandardSession writeObject WARNING: Cannot serialize session attribute cart for session 2F9FF7A5ABC3620BD5B3BC0C4D46C558 java.io.NotSerializableException: org.apache.tomcat.jdbc.pool.DisposableConnectionFacade at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1183) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
We've implemented the Whitelist and there's an application I need to use the Force attribute with, however, I'm unable to get this to work. As I read it, this code says use Java 1.6_24 for Example.com and any other applications are blocked from running. There are three versions of Java installed - 1.6_24, 1.7_65 & 1.8_25. The Java console shows 1.8_25 being called.
Here's the ruleset.
<ruleset version="1.1+"> <rule> <id location=https://example.com /> <action permission="run" version="1.6_24" force="true" /> </rule> <rule> <id /> <action permission="block"> <message> This application is blocked due to Java restrictions, please contact the Service Desk for assistance.</message> </action> </rule></ruleset>
I also tried
<action force="true" permission="run" version="1.6.0_24" /> and also <action force="true" version="1.6.0_24" permission="run" />.
The Java console is still showing version 1.8.0_25.
I'm looking to figure out if it's possible to do the following:
HttpSession session = request.getSession(); session.setAttribute('name', 'Jane_Doe'); // more code here session.setAttribute('name', 'John_Doe');
Obviously, you can use the HttpSessionAttributeListener to determine which attribute has changed. However, it doesn't return the new value but rather the old one.
You can use the HttpSessionEvent listener to determine when a session object has been changed.
Is there a way you can determine when a session object changes (and it does NOT occur when the setAttribute method is called...) and determine the updated key:value pair?
i have a field that varies from 10 to 3000 VARCHAR in DB. A field called IDTEXT in a database that can be even a single word or up to a max of 3000. I want to display that in a form. Based on its size i want to very the size of the <h:inputTextarea>. How can i do it..will i be able to set row property from bean?
Being new to java I am a bit lost as to why my session attribute for this banking app wont add the deposits to the session var... it just keeps going back to the amount I set it to originally - so if I set the beginning balance to 3000 then deposit 100 it becomes 3100, but if I then try deposit another amount eg. a extra 200 it becomes 3200 not 3300 like it should be !!
import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; import java.net.*; import java.text.DecimalFormat; public class SessionBank extends HttpServlet
why my session attribute for this banking webapp wont add the deposits to the session var... it just keeps going back to the amount I set it to originally - so if I set the beginning balance to 3000 then deposit 100 it becomes 3100, but if I then try deposit another amount eg. a extra 200 it becomes 3200 not 3300 like it should be !!
you can also refer this link Local variables in java?Local variables in java?To meet temporary requirements of the programmers some times..we have to create variables inside method or bock or constructor such type of variables are called as Local Variables.
----> Local variables also known as stack variables or automatic variables or temporary variables
----> Local variables will be stored inside Stack.
-----> The local variables will be created while executing the block
in which we declared it and destroyed once the block completed. Hence the scope of local variables is exactly same as the block in which we declared it.
package com.javatask.in; class A{ public static void main(String args[]){ int i=0; // Local variable
