Writing Data To A File Using PrintWriter
Oct 25, 2014
I am creating a car simulator that simulators the odometer and fuel gauge on a car. I want to print the results to a text file but it seems to be printing only the last two lines instead of all of them. How can I make it so it doesn't overwrite the previous input?
Here's my main method:
public static void main(String[] args) throws FileNotFoundException {
CarInstrumentSimulator carInstrumentSimulator = new CarInstrumentSimulator();
FuelGauge gas = carInstrumentSimulator.new FuelGauge();
[Code].....
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Jun 13, 2014
Does printwriter always truncates the existing file to 0 size before adding any new data ??
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May 1, 2015
I thought you can use PrintWriter to write to the console but when I run the following code I only get "abc" printed to the console.
import java.io.*;
class Class1{
public static void main(String...abc) throws Exception{
PrintWriter writer = new PrintWriter(System.out);
writer.println("test");
System.out.println("abc");
}
}
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Dec 15, 2014
I need to write a program that, when a button is pressed, will add the user input to a table AND write it to a sequential data file. I have everything done accept for how to write the data sequentially(all input data on the same line in the file). The following is part of the code:
private void submitButtonActionPerformed(java.awt.event.ActionEvent evt) {
DefaultTableModel dtm = (DefaultTableModel)jTable1.getModel();
dtm.addRow(new Object[]{donorName.getText(),charityName.getText(),donationAmmount.getText()});
//Adds user input to the table
try
{
FileWriter writer = new FileWriter("FundraisingInformation.txt",true);//Creates file or adds to it
BufferedWriter bw = new BufferedWriter(writer);
[code].....
I would need the file output to be in the following format:
donorName charityName donationAmmount
As I said, using the .write(bw) i know how to make it look like:
donorName
charityName
donationAmmount
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May 25, 2014
My program creates a file but cannot write to it and i cannot figure out why.
How can i fix this code so that the FileOutputStream writes the String "Output" to the file HighScore.
public boolean ScoreWriter(int HighScore, int ScoreNum){
boolean writ = true;
System.out.println(HighScore + " " + ScoreNum);
try{
File ScoreFile = new File("HighScore");
if (!ScoreFile.exists()){
ScoreFile.createNewFile();
}else if (ScoreFile.exists()){
ScoreFile.delete();
ScoreFile.createNewFile();
[code].....
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Jul 16, 2014
When I am trying to read data from BufferedReader and writing into excel using FileOutputStream object with POI APIs then i am getting the data in excel file in bad formats. you can check the log file and excel file attached for more information.
Here my problem is I cannot use BufferedWriter in place of FileOutputStream because POI class XSSFWorkbook only have one write method and we can only pass FileOutputStream class object there.
public void readFile()throws IOException {
BufferedReader inputStream = null;
FileInputStream fis=null;
InputStreamReader isr = null;
//Blank workbook
XSSFWorkbook workbook = new XSSFWorkbook();
[Code] .....
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Oct 11, 2014
I'm having a bit of trouble with using the Scanner and the Printwriter. I start with a file like this (1 = amount of Houses in the file)
1
FOR SALE:
Emmalaan 23
3051JC Rotterdam
7 rooms
buyprice 300000
energylevel C
The user gets (let's say for simplicity) 3 options:
1. Add a House to the file,
2. Get all Houses which fullfil requirements (price, FOR SALE / SOLD etc.) and
3. Close the application.
This is how I start:
Scanner sc = new Scanner (System.in);
while (!endLoop) {
System.out.println("Make a choice);
System.out.println("1) Add House");
System.out.println("2) Show Houses");
System.out.println("3) Exit");
int choice = sc.nextInt();
Then I have a switch for all of the three cases. I keep the scanner open, so Java can get the user input (house = for sale or sold, price = ... etc). If the user chose option 1, and all information needed is inputted and scanned, the House will be written to the file (which looks like what I typed above).
For this, I use try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("Makelaar.txt", false)))). This works perfectly (at least so it seems.)
If the user chose option 1, and all requirements are inputted and scanned, the Houses will be read (scanner) from the file and outputted. For this I use the same Scanner sc. This also works perfectly (so it seems atleast).
My problem is as follows: If a House has been added, I can only read the House(s) which were already in the file. Let's say I have added 2 houses, and there were from the start 3 houses. If option 2 is chosen, the first 3 houses will be scanned perfectly. An exception will be caught for the remaining 2 (just added) Houses. How can I solve this? I tried to close the Scanner, and reopening it, but apparently Java doesn't agree with this
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Nov 7, 2014
This is a college course assignment that consists of classes TotalSales and TotalSalesTest.In the main program I have created a two dimensional array to output a columnar layout with cross-totals in 4 rows and 5 columns. This program outputs sales totals by row for each sales person(1 - 4) and output by column for products(1 - 5). I have created extra elements in the array to store total for rows and columns. So far both classes compiles. The problem is that although the PrintWriter creates a notepad file, it doesn't print to it. I don't seem to understand the input and output methods completely. I finished another program similar to this using basically the same try and catch that read the file and printed out a document in notepad. Here is the code and I'll try include the input file.
import java.util.Scanner;
import java.io.*;
public class TotalSales {
private int salesPerson; //declare class variable
private int productNumber;//declare class variable
[code]....
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Jun 24, 2015
I have a program which consist of several classes. The program reads a pom file and parses the data and then writes the data to a static table. The issue I'm having is with writing my LIB file data to my table. In the HtmlDataTable Class Im trying to write the files that are read in the lib directory to the table. My table currently consist of 3 columns (missing jar files,Lib Directory files, and POM file data) currently Im only able to write the missing jar files data to my table. In the HtmlDataTable class there is a for statement where I write the missing jar file data to my table. Im also trying to write the contents of the Lib directory within this statement as well. This is where I'm having my issue. My other classes consist of a SAX parser which parses the xml file, a class that creates my static table and a class that compares the jar files in my lib directory to the jar files in my pom file. . Theres a lot of code so I included the parts I felt were useful. If needed I can include the other classes as well.
public class ReadPomFile extends DefaultHandler {
public static void main(String[] args) {
try {
// obtain a SAX based parser to parse XML document
[Code].....
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Feb 17, 2015
You are given a file containing the names and addresses of company employees from many years ago that your manager has asked you to import into a database. You can use a CSV file and your database application to load the file, but the file your manager gave you was exported from an old, non-standard accounting system. Here is its format:
Fred|Flintstone
1212|Bedrock
Austin|Texas
Harry|Potter
1234|Hogwarts Road
[Code] .....
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Aug 20, 2014
If I am using the File object to read a file and PrintWriter object to write to a separate file, can I use them under one method. Or is the File one method and the PrintWriter another method?
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Apr 29, 2015
private static void getTablas(int num) {
//ciclos anidados
System.out.print("x");
//linea horizontal
for (int i = 1; i <= num; i++) {
System.out.printf("%3d ",i);
[Code] .....
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Mar 6, 2014
i have to write more than 100000 rows in a excel sheet (file size more than 20 MB) via java.
when i use XSSF, i am getting below Error.
java.lang.OutOfMemoryError: Java heap space
at org.apache.xmlbeans.impl.store.Saver$TextSaver.resize(Saver.java:1592)
at org.apache.xmlbeans.impl.store.Saver$TextSaver.preEmit(Saver.java:1223)
at org.apache.xmlbeans.impl.store.Saver$TextSaver.emit(Saver.java:1144)
[Code]....
when i use HSSF , i am getting the below Error.
java.lang.OutOfMemoryError: Java heap space
I have tried increasing the java heap size , by giving upto -Xms1500m -Xmx2048m
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Jul 10, 2014
I am using a FileOutputStream to write a file but it is not writing data to destination file from source
Here is my code
package org.kishor.outputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class WriteToaFile {
public static void main(String args[]) throws IOException
{
FileOutputStream fout = null;
[code]...
find a bug where i am wrong why data is not on output file?
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Sep 9, 2014
I've looked at multiple sources and everyone is saying different stuff. Which one should I be using? FileWriter/FileReader, other people was saying PrintWriter, and one even said : "Formatter" which is the one I'm doubting mostly. My purposes for writing files is for like saving maps, saving high scores, etc.
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Jan 10, 2014
I have accountsData.txt file in my default package, this is the file it should be writing to and reading from.
There is an ATM class, which has the main in it. From here the program is supposed to work like an atm, you type in your account number and can withdraw or deposit. It is supposed to then write the changes to the file.
//Read from a file.
public void loadAccounts(String inputFileName) throws IOException
{
Scanner fin = new Scanner(new File(inputFileName));
// Variables to store the values.[/color]
int account = 0;
double balance = 0.0;
[Code] .....
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Nov 29, 2014
I want a servlet to write a file inside WEB-INF folder
I tried these things
File file =new File("feedback.txt");
or
File file =new File("/feedback.txt");
or
File file =new File("WEB-INF/feedback.txt");
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Apr 20, 2014
I am trying to write a Float Array to a file but it is only writing the last line of the array to a file. I have also attached the entire assignment as a zip file with all required files. Here is the part of the code I am having issues with:
Java Code:
for (int i = 0; i < differenceArray.length; i++){
System.out.println ("Date: "+ dateArray[i] + " Opening: " + dataArray[i][2] + " Closing: "+ dataArray[i][5] + " Difference: " + differenceArray[i]);
try(FileWriter writer = new FileWriter("C: emp" + fileName + ".txt")){
writer.write(Float.toString(differenceArray[i]));
[Code] .....
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Jul 19, 2014
There are several ways in Java to create a text file and write to it. But which is the most effective way among them? Any example with code?
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Dec 4, 2014
I need to read lastname, firstname, and ssn from a text file and sort them based on oneof those three creiteria. Here is my person class:
public class Person implements Comparable {
private String lastName, firstName, ssn;
private static int sortBy = 1;
public static final int LASTNAME=1, FIRSTNAME=2, SSN=3;
public void setSortMethod(int method) {
if(method != LASTNAME && method != FIRSTNAME && method != SSN) {
throw new IllegalArgumentException();
} else {
[code]....
how to sort my info and store it into an array and then write that info into my new file.
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Jan 13, 2014
I was writing a method to read a file. I did not think it through and gave the return type as void and modifier as static but I am not sure if it has to be void. How do you decide the return type of the method? Is there a good rule of thumb in such cases? Also, does the use of static needs to be done sparingly?
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Jan 11, 2015
How to output text to a file, so I had to do my own research on google, but the results I found were confusing. I finally got my code to write to a file, but I cannot figure out how to append a new line. I know what part of the code is incorrect, but I don't know how to fix it. here is what I have right now:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Scanner;
public class highscore {
public static void main(String[] args) throws IOException {
[Code] ....
I can see the last two lines are telling the program to overwrite the first input with the second. Of course if I pick a different file name for the second output, I get another file with the second input, but I need to learn how to append as well.
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Feb 8, 2014
I'm writing a program to dynamically update an xml file to add, delete, and edit entries in the file. I've run into an issue with the add method because when I write into the file, a random letter is added before the line. EX:
I want to add "<item> ..." to the end of the list of entries, but when it is added, this is what is added "Z <item> ..."The spacing for the <item> is correct, however, I don't see where or why the Z is added.
public static void insertItem(Item i)
{
try {
String insert = " <item>";
String text = "";
Scanner in = new Scanner(file);
[code]....
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Aug 20, 2014
I obtained the following code online which purports to get the content of the JFrame:
public BufferedImage getScreenShot(
Component component) {
BufferedImage image = new BufferedImage(
winWidth,
[Code] .....
Then I write out the image with the following code:
BufferedImage screenShot = getScreenShot(c);
try{
File outputfile = new File(
[Code] .....
When I double-click on the resulting file, all the images show up as black rectangles in Windows Photo Viewer. Yet the associated buffered image displays correctly in the window. I've tried 'jpg, 'png', and 'bmp' extensions, with matching formats in the write. I am using Win-7 64-bit. and jdk8 with matching jre.
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May 29, 2014
I'm working on a project for class that asks me to record punch-in and punch-out times for employees. However, I am having difficulty figuring out where I am going wrong as none of the information will write to the text file in the ArrayList that I have created. The code is as follows:
import java.text.*;
import java.util.*;
import java.io.*;
import java.nio.file.*;
public class TimeClockApp {
// declare class variables
private static EmployeeDAO employeeDAO = null;
[Code] .....
I want to keep the coding as simple as possible as I am new to Java, and have spent hours upon hours trying to figure this all out. The console output looks like this:
Welcome to the Punch-In/Punch-Out Screen
Please choose an option below:
I. Punch In
O. Punch Out
Choice: i
PUNCH IN
--------
Enter Employee ID:
8
8Punch-In Date & Time: 2014/05/28 22:44:26
[]
Press enter to return to the main screen:
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Dec 20, 2014
I'm doing this assignment in which i have to write some products in csv file...but as u can see in csv file two products are same "Cooking Oil"..so any method that can add two same product's quantity and their amount and write them in file
import java.util.*;
import java.io.*;
public class SalesbyTransactionMonth{
private static final String fileName = "Data.txt";
private static final String fileName1 = "sales_by_trans_month.csv";
String line = "";
[Code] ....
Attached image(s)
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