Random Access File - How To Retrieve Particular Set Of Data
May 4, 2015
I am creating a read/write, RandomAccessFile that I will use to store several student ID and gpa score. What I don't understand is how I should go about retrieving a particular set of data.
public class ReadWrite {
static Scanner keyboard = new Scanner(System.in);
static String fileName = "Stu.dat";
static RandomAccessFile raf;
public static void main(String [] args) throws FileNotFoundException, IOException {
[Code] .....
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Jul 10, 2014
I have a random access file stream. I have below code I want to written data that is currently pointed by pointer till the end and display that data on System.out Stream but it is not working my code is
//Create a Random Access File
java.io.RandomAccessFile random=new java.io.RandomAccessFile("D:/input.txt","rw");
//Position the pointer to a seek
try {
random.seek(300);
long pointer=random.getFilePointer();
System.out.println("Current Pointer is:"+pointer);
int a;
while((a=random.read())!=-1) {
System.out.println(a);
}
Where am I wrong? Although it is returning actual position of pointer in pointer using
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Jul 11, 2014
I'm trying to write data for three products to a random access file, but I have a problem. Each product has a code and a price. After writing them to my file, I want to get to the second field or product. I do this by getting the length for each record, and multiplying it by the field number I want to go to. I use the result for the seek() method of the RandomAccessFile object. It is giving me an EOFException, but when I use 0 for the seek method i get the data for the first poduct or field.
Java Code:
public static void main(String[] args) {
final int RECORD_LENGTH = 16;
try(RandomAccessFile productsOutput = new RandomAccessFile("C:UsersalfonsoDesktopBinaryTestRandom.ran", "rw")) {
String[] codes = {"java", "jsps", "txtp"};
double[] prices = {49.5, 19.9, 29.9};
for(int i = 0; i < codes.length; i++) {
[Code] .....
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Dec 8, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code] .....
And then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
These continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quantity after the second comma.....
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Dec 9, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data. Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code]...
these continue for about 40-50 entries, they are not seperated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name seperated with spaces, then price after a comma, then quanity after the second comma.....
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Dec 8, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
//Constructor
public Product( String pName, double price, int quanity )
[code]....
and then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
these continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quanity after the second comma.....
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Oct 26, 2014
I need to write a program that will create an inventory file as a random access file. The problem that I am having is that among the things I need to add to the random access file is a "car name". Since random access files are byte based I don't know how I could possibly write and then read a string value.
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Jul 12, 2014
I'm trying to save a picture from byte arrays using RandomAccessFile. The file appears but doesn't open (like its corrupted).
I'm using the bittorent protocol which gives a SHA-1 hash that I compare all the bytes with to verify the data. All the bytes pass the hash check and all the hashes are checked. So I'm pretty sure I'm getting all the bytes correctly.
Is there anything I can do that could tell what's going wrong?
public RUBTClient(final TorrentInfo2 tInfo, final String outFileName) {
...
this.outFileName = outFileName;
File destined = new File(outFileName);
try {
destined_file = new RandomAccessFile(destined, "rw");
destined_file.setLength(tInfo.file_length);
} catch (FileNotFoundException e1) {
[Code] .....
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Apr 2, 2014
I have retrieve the data in listbox from my database already and now again i want to select the data from this listbox and query on it , is it possible?
For Ex i have listbox as follows
<h4>Models For Selected Pattern:</h4>
</br>
<select Name="drop_model" multiple="true">
<%
try {
Class.forName(driver).newInstance();
conn = DriverManager.getConnection(url,username,userPassword);
Statement stmt = conn.createStatement();
[Code] ....
In this listbox some values are retrieved from database as
<option value="xyz">xyz</option>
<option value="pqr">pqr</option>
<option value="abc">abc</option>
<option value="lmn">lmn</option>
I want to select this values from listbox and query on them....
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Dec 23, 2014
I am trying to retrieve data from my database by joining my tables. So far i have managed to join my four tables in my database and retrieve all the information in that table. Now what i want to do is create a prepared statement in java that allows me to retreive certain data. Here is my joining query.
SELECT student.idNumber,student.names, student.surname,
course.description,
coursemarks.mark,
class.form,class.id
FROM `student`
LEFT JOIN `coursemarks` on student.idNumber = coursemarks.studentid
LEFT JOIN `course` on course.courseid = coursemarks.courseid
LEFT JOIN `class`on student.idNumber = class.studentID;
What I want is to select all the data depending on the class passed and the form passed, e.g a person might decide to select a certain form only or a certain form and class
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Aug 31, 2014
I am creating a small application.I have a jsp font page.i have a jdbc connection code.I have a sample table in my database.i want to retrieve datas from the database and display them in the view page.
My questions are:
-Where do i have to write jdbc code?
-How can i display the retrieved data in the display page?
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Jan 22, 2014
We created one web application which runs on tomcat 7.0.35 using spring mvc 3.0 . Its working perfectly on 32-bit windows machine in IE 8 on Windows 7 OS, when we tried to run this on 64-bit windows 2008 Server, jquery is not working. Also I populate data from Pop-up JSP to parent JSP, and it works 3/10 times only and does not work always.
We used the following jquery plugins in our project
jquery 1.8.3
jquery.ui.custom.1.9.2
jquery.ui.custom.min-1.9.
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Apr 1, 2015
I want to retrieve the data from this table given below and insert that data in the database in the next servlet
package com.sk;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
[Code] .....
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Aug 26, 2014
We have implemented SSO based on cookies.
1. user clicks the link in our app (www.app1.com) , cookie set up done (respose.addCookie)
2. request will redirect to (third party software, cant change anything)
3..Here if the SSO enabled, it will redirect to the another URL (www.issues.app1.com) .
4,Have to get the cookie(User details) set in #1 here and validate.
Its working fine .But if we change the www.app1.com to www.abc.com , SSO is not working. We cant change www.issues.app1.com.
How to share the cookie in cross domain across 3 apps ? because middle app , we dont have control over it.
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Oct 3, 2014
I've been unable to figure out how to access an objects data from another class. I ended up missing a lesson in java and haven't been able to catch up on this topic on my own through my textbook.
Error: has private access
Code:
public class TestCoffeeDrinker {
public static void main(String[] args) {
Coffee latte = new Coffee("Starbucks Tall Latte", 2.85);
Coffee mocha = new Coffee("Starbucks Grande Mocha", 3.95);
Coffee mcdonalds = new Coffee("McDonalds McCafe", 0.99);
System.out.println(mcdonalds.toString());
[Code]...
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Apr 23, 2014
I want to keep count of how many students are in my array. the array i made up of objects from other classes. like the class Student how do i do this. i have tried contains but better way it to to a loop to go through the array and determine if each object is a particular type but i don't know how to do this. here is the code
import java.util.*;
import java.util.ArrayList;
public class Driver {
public static void main(String[] args){
/* Comments required
PersonFileReader pfr = new PersonFileReader("person.dat");
ArrayList<Person> testData = pfr.readData();
Database db = new Database(testData);
[Code] .....
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Mar 29, 2014
I need my java program to insert data into my access database. I get no errors in my code, but it never inserts, deletes the data in my database. Here is my code:
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
public class INS extends Frame implements ActionListener{
Frame f;
Label l1, l2;
TextField t1, t2;
Button b1, b2, b3, b4, b5;
Connection c;
[Code] ....
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May 6, 2014
I have been asked to write a program with 3 classes(an interface, a store and a product class) and I have been going ok until I need to display data on the interface that is held in the product class. At the moment the code will compile fine but when I run the program and try to use the writeOutput() method I get a stack overflow error.
I realise now that it is because of a non-terminating recursive call, however I can not think of a solution on how to fix the problem. And just to clarify, what I am aiming to do is have the MatesTerminal class display the data for name that is stored in the Product class(I have no way of determining which product to display at this time, so I would like to be able to display the data for all three products if possible). Anyway this is what I have so far:
The method from the MatesTerminal Class:
private void writeOutput() {
int productChoice;
Scanner console = new Scanner(System.in);
[Code].....
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Feb 11, 2015
I'm new to java and trying to insert data from a cachedrowset into MS Access database, Below is the error code that I get after running my program.
java.sql.SQLException: Parameter-Set has missing values.
The SQL test table that I am using.
Java Code:
create table book (
TITLE_ID CHAR(3 BYTE)
TITLE_NAME VARCHAR2(40 BYTE)
TYPE VARCHAR2(10 BYTE)
PUB_ID CHAR(3 BYTE)
PAGES NUMBER(38,0)
PRICE NUMBER(5,2)
SALES NUMBER(38,0)
PUBDATE DATE
CONTRACT NUMBER(38,0)
); mh_sh_highlight_all('java');
SQL table values with blanks:
Java Code: TITLE_ID TITLE_NAME TYPE PUB_ID PAGES PRICE SALES PUBDATE CONTRACT
T01Java history P0111121.99 566 01-AUG-001
T02Oracle history P0311419.95 9566 01-APR-981
T03SQL computer P0212239.95 25667 01-SEP-001
T04C++ psychologyP0451112.99 13001 31-MAY-991
T05Python psychologyP041016.95 201440 01-JAN-011
[code]....
Below is the piece of java code that I am using.
Java Code:
public void insertAccessTable(Connection connection, CachedRowSet CRS_insertAccess) throws Exception
{
try
{
RowSetMetaData metaData = (RowSetMetaData)CRS_insertAccess.getMetaData();
ArrayList<ArrayList<String>> TwoDimArrList = new ArrayList<ArrayList<String>>();
TwoDimArrList.add(new ArrayList<String>());
TwoDimArrList.add(new ArrayList<String>());
ArrayList<String> ColArrList = new ArrayList<String>();
for (int column = 1; column <= metaData.getColumnCount(); column++) {
[code]....
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May 11, 2014
I have following methods, which I call from the Event Dispatcher Thread:
public void setTitle(String title) {
Platform.runLater(() -> stage.setTitle(title));}
public String getTitle() {
return stage.getTitle(); // <- Access from outside JFX App Thread ok?}
Is it thread-safe, when the getter-Method just return the value like the example show? Or must I create a Runnable, so stage.getTitle() is called inside the Java Application Thread? How I return the value then?
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Nov 21, 2014
So let's say i have an executable jar and inside that jar is a bunch of files. How do I access files within my jar?
Assuming like, a main class is currently running and that is what's inside the manifest file as the main class inside that executable jar..
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Apr 9, 2015
I would like to understand how does multipart/form-data works during file upload scenario's, Does it chunks the data from client to server while transferring the files ?
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Mar 21, 2015
By using FileReader, FileWriter and their constituents, I am creating a file to contain employee information ( name, age, hours, etc. ). The user is to input all of the data on a single line and we were asked to implement StringTokenizer to assign that data to the file. I have never used the StringTokenizer before, but I have a rough idea how it is to function. I used pw.println to test what I have so far, now I would like to let the user build the initial file with the "first employees" of the company, and then view the file, and then go back and append new employee data to that same file. My question is, how can I take the user input as a StringTokenizer and add that to the file?
In the for loop below, I thought I would see if it would work, but it does not. The loop only executes once and does not allow me to enter data.
public class Records {
public static void main(String [] args) throws IOException {
Scanner input = new Scanner(System.in);
FileWriter fw = new FileWriter("dbs3.java");
BufferedWriter bw = new BufferedWriter(fw);
PrintWriter pw = new PrintWriter(bw);
System.out.println("NEW EMPLOYEE DATA SHEET");
System.out.print("Number of new employees: ");
int number = input.nextInt();
[Code] ....
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Apr 23, 2015
I am trying to remove a line based on user input. myFile.txt looks like:
Matt
Brian
John
However when I enter "Brian" (to remove this line), It is deleted on the temp file (myTempFile.txt), but not renamed back to the original file (myFile).
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
[code]....
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Nov 30, 2014
I am splitting a zip file and want to name each fragment with a random name. I want to use java coding for generating this random file name.
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Feb 8, 2015
I am creating a program where it reads the data inside a file and then places this data into arrays. The file I created has numbers 1-30 in it, file named, testing1.txt .
Java Code:
public static void main(String[] args) {
// TODO Auto-generated method stub
// Variables Declaration Section
//******************************
BufferedReader br;
String sCurrentLine;
String str;
[Code] ....
My issue is that the 'str' value is not initialized, but if I initialize it, it ruins the code. I'm not sure what to do in the situation.
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