Deleting a line from a text file & opening a project from another project

hi
im doing project on linux redhat 8.0 using java (jbuilder 8). I need to
open a project2 from behind a menu item in project1. I tried importing
the package of project2 and then initializing a constructor of main
class of project2 in project1(behind the "open project2" menu item) but
i dont know where to place the class files of project2 so im getting a
compilation error(when compiling project1) that unable to locate
imported package files.
is there any other way of doing this
like making an .exe file of project2??? if so, then pls tell me how.
Another problem is i want to delete a line of selected text from a text
file
using java. is there a method for that or any other way?
Anybodyyyy have any ideasss?
Alisha

Cross- and double-posted: http://forum.java.sun.com/thread.jspa?threadID=645244

Similar Messages

Delete specified line in a text file

can anyone help me??
how to remove specific line in a text file using java?? thank thanks

Read the file, write a new one, and when you write skip over the line you want to delete.

By Java how to delete some lines in a text file containg some character?

Hello All,
I am having a text file [Basically It is a Sql File]. its containing some commented lines.
All i need to do is, By using a java Method I have to delete All the commented lines in That file .....
For Example if My file is like following.
/**** Commented By Kannan *********/
Select * From Employee;
go
/******************** Commented by Others ********/
Select * From DevMembers;
go
/*** Ends here **********/
And the output file would be
Select * From Employee;
go
select * From DevMembers;
go
can Anyone Help me in this regards,
Akram Kannan

BufferedReader should probably wrap the FileReader if you will be reading line-by-line. Same with the Writer.
And a simple -
if ( "/*".equals(record.substring(0,1) ) ... should handle the comment locations bit.
Message was edited by:
abillconsl

Delete lines from a text file

i need to delete (or replace them with white space) a few lines from a text file. I have a text file with first few lines & last few lines containing "<"or ">". I need to delete/replace with white space, the entire line. i need to do this urgently
Could some one please tell me how to do this?

the file can be of size 8MB or more. i get this file
every week from a third party. So the size is not
constant. I need to remove/replace with white space,
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seperated values which i need to load to database
using sqlldr. But still not sure abt how to remove
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i need to read this file, replace the lines as i read
them and write the replaced string back to the file &
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P.S. It will probably be a mistake if you try to edit the original file in place.

Interactive Bar/pie chart and line graph, data from excel/text file -urgent

Hi,
I have a huge data in excell sheet which keeps updating every month. Data basically consists of service provider and there respective subscribers from various regions of the country over the years. The requirement is to give the viewers an interactive page where in they can make various combinations and can compare, cross examine data according to thier choice.
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The site is hosted on a red hat linux server. how can a connection to the excel spreadsheet be made or is it possible to read from the text file if the entire data is exported to a text file.
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I certainly wouldn't pay for the graphing package at the previous link. check out http://www.object-refinery.com/jfreechart/ for a free, open-source, much better looking graphing package.

Reading a Random Line from a Text File

Hello,
I have a program that reads from a text file words. I currently have a text file around 800KB of words. The problem is, if I try to load this into an arraylist so I can use it in my application, it takes wayy long to load. I was wondering if there was a way to just read a random line from the text file.
Here is my code, and the text file that the program reads from is called 'wordFile'
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
public class WordColor extends JFrame{
     public WordColor(){
          super("WordColor");
          setSize(1000,500);
          setVisible(true);
          add(new WordPanel());
     public static void main(String[]r){
          JFrame f = new WordColor();
class WordPanel extends JPanel implements KeyListener{
     private Graphics2D pane;
     private Image img;
     private char[]characterList;
     private CharacterPosition[]positions;
     private int charcounter = 0;
     private String initialWord;
     private File wordFile = new File("C:\\Documents and Settings\\My Documents\\Java\\projects\\WordColorWords.txt");
     private FontMetrics fm;
     private javax.swing.Timer timer;
     public final static int START = 20;
     public final static int delay = 10;
     public final static int BOTTOMLINE = 375;
     public final static int buffer = 15;
     public final static int distance = 4;
     public final static Color[] colors = new Color[]{Color.red,Color.blue,Color.green,Color.yellow,Color.cyan,
                                                                      Color.magenta,Color.orange,Color.pink};
     public static String[] words;
     public static int descent;
     public static int YAXIS = 75;
     public static int SIZE = 72;
     public WordPanel(){
          words = readWords();
          setLayout(new BorderLayout());
          initialWord = getWord();
          characterList = new char[initialWord.length()];
          for (int i=0; i<initialWord.length();i++){
               characterList[i] = initialWord.charAt(i);
          setFocusable(true);
          addKeyListener(this);
          timer = new javax.swing.Timer(delay,new ActionListener(){
               public void actionPerformed(ActionEvent evt){
                    YAXIS += 1;
                    drawWords();
                    if (YAXIS + descent - buffer >= BOTTOMLINE) lose();
                    if (allColorsOn()) win();
     public void paintComponent(Graphics g){
          super.paintComponent(g);
          if (img == null){
               img = createImage(getWidth(),getHeight());
               pane = (Graphics2D)img.getGraphics();
               pane.setColor(Color.white);
               pane.fillRect(0,0,getWidth(),getHeight());
               pane.setFont(new Font("Arial",Font.BOLD,SIZE));
               pane.setColor(Color.black);
               drawThickLine(pane,getWidth(),5);
               fm = g.getFontMetrics(new Font("Arial",Font.BOLD,SIZE));
               descent = fm.getDescent();
               distributePositions();
               drawWords();
               timer.start();
          g.drawImage(img,0,0,this);
     private void distributePositions(){
          int xaxis = START;
          positions = new CharacterPosition[characterList.length];
          int counter = 0;
          for (char c: characterList){
               CharacterPosition cp = new CharacterPosition(c,xaxis, Color.black);
               positions[counter] = cp;
               counter++;
               xaxis += fm.charWidth(c)+distance;
     private void drawThickLine(Graphics2D pane, int width, int thickness){
          pane.setColor(Color.black);
          for (int j = BOTTOMLINE;j<BOTTOMLINE+1+thickness;j++){
               pane.drawLine(0,j,width,j);
     private void drawWords(){
          pane.setColor(Color.white);
          pane.fillRect(0,0,getWidth(),getHeight());
          drawThickLine(pane,getWidth(),5);
          for (CharacterPosition cp: positions){
               int x = cp.getX();
               char print = cp.getChar();
               pane.setColor(cp.getColor());
               pane.drawString(""+print,x,YAXIS);
          repaint();
     private boolean allColorsOn(){
          for (CharacterPosition cp: positions){
               if (cp.getColor() == Color.black) return false;
          return true;
     private Color randomColor(){
          int rand = (int)(Math.random()*colors.length);
          return colors[rand];
     private void restart(){
          charcounter = 0;
          for (CharacterPosition cp: positions){
               cp.setColor(Color.black);
     private void win(){
          timer.stop();
          newWord();
     private void newWord(){
          pane.setColor(Color.white);
          pane.fillRect(0,0,getWidth(),getHeight());
          repaint();
          drawThickLine(pane,getWidth(),5);
          YAXIS = 75;
          initialWord = getWord();
          characterList = new char[initialWord.length()];
          for (int i=0; i<initialWord.length();i++){
               characterList[i] = initialWord.charAt(i);
          distributePositions();
          charcounter = 0;
          drawWords();
          timer.start();
     private void lose(){
          timer.stop();
          pane.setColor(Color.white);
          pane.fillRect(0,0,getWidth(),getHeight());
          pane.setColor(Color.red);
          pane.drawString("Sorry, You Lose!",50,150);
          repaint();
          removeKeyListener(this);
          final JPanel p1 = new JPanel();
          JButton again = new JButton("Play Again?");
          p1.add(again);
          add(p1,"South");
          p1.setBackground(Color.white);
          validate();
          again.addActionListener(new ActionListener(){
               public void actionPerformed(ActionEvent evt){
                    remove(p1);
                    addKeyListener(WordPanel.this);
                    newWord();
     private String getWord(){
          int rand = (int)(Math.random()*words.length);
          return words[rand];
     private String[] readWords(){
          ArrayList<String> arr = new ArrayList<String>();
          try{
               BufferedReader buff = new BufferedReader(new FileReader(wordFile));
               try{
                    String line = null;
                    while (( line = buff.readLine()) != null){
                         line = line.toUpperCase();
                         arr.add(line);
               finally{
                    buff.close();
          catch(Exception e){e.printStackTrace();}
          Object[] objects = arr.toArray();
          String[] words = new String[objects.length];
          int count = 0;
          for (Object o: objects){
               words[count] = (String)o;
               count++;
          return words;
     public void keyPressed(KeyEvent evt){
          char tempchar = evt.getKeyChar();
          String character = ""+tempchar;
          if (character.equalsIgnoreCase(""+positions[charcounter].getChar())){
               positions[charcounter].setColor(randomColor());
               charcounter++;
          else if (evt.isShiftDown()){
               evt.consume();
          else{
               restart();
          drawWords();
     public void keyTyped(KeyEvent evt){}
     public void keyReleased(KeyEvent evt){}
class CharacterPosition{
     private int xaxis;
     private char character;
     private Color color;
     public CharacterPosition(char c, int x, Color col){
          xaxis = x;
          character = c;
          color = col;
     public int getX(){
          return xaxis;
     public char getChar(){
          return character;
     public Color getColor(){
          return color;
     public void setColor(Color c){
          color = c;
}

I thought that maybe serializing the ArrayList might be faster than creating the ArrayList by iterating over each line in the text file. But alas, I was wrong. Here's my code anyway:
class WordList extends ArrayList<String>{
long updated;
WordList readWordList(File file) throws Exception{
WordList list = new WordList();
BufferedReader in = new BufferedReader(new FileReader(file));
String line = null;
while ((line = in.readLine()) != null){
    list.add(line);
in.close();
list.updated = file.lastModified();
return list;
WordList wordList;
File datFile = new File("words.dat");
File txtFile = new File("input.txt");
if (datFile.exists()){
ObjectInputStream input = new ObjectInputStream(new FileInputStream(datFile));
wordList = (WordList)input.readObject();
if (wordList.updated < txtFile.lastModified()){
    //if the text file has been updated, re-read it
    wordList = readWordList(txtFile);
    ObjectOutputStream output = new ObjectOutputStream(new FileOutputStream(datFile));
    output.writeObject(wordList);
    output.close();
} else {
//serialized list does not exist--create it
wordList = readWordList(txtFile);
ObjectOutputStream output = new ObjectOutputStream(new FileOutputStream(datFile));
output.writeObject(wordList);
output.close();
}The text file contained one random sequence of letters per line. For example:
hwnuu
nhpgaucah
zfbylzt
hwnc
gicgwkhStats:
Text file size: 892K
Serialized file size: 1.1MB
Time to read from text file: 795ms
Time to read from serialized file: 1216ms

Reading one line from a text file into an array

i want to read one line from a text file into an array, and then the next line into a different array. both arays are type string...i have this:
public static void readAndProcessData(FileInputStream stream){
     InputStreamReader iStrReader = new InputStreamReader (stream);
     BufferedReader reader = new BufferedReader (iStrReader);
     String line = "";
     try{
     int i = 0;
          while (line != null){
               names[i] = reader.readLine();
               score[i] = reader.readLine();
               line = reader.readLine();
               i++;
          }catch (IOException e){
          System.out.println("Error in file access");
this section calls it:
try{
     FileInputStream stream = new FileInputStream("ISU.txt");
          HighScore.readAndProcessData(stream);
          stream.close();
          names = HighScore.getNames();
          scores = HighScore.getScores();
     }catch(IOException e){
          System.out.println("Error in accessing file." + e.toString());
it gives me an array index out of bounds error

oh wait I see it when I looked at the original quote.
They array you made called names or the other one is prob too small for the amount of names that you have in the file. Hence as I increases it eventually goes out of bounds of the array so you should probably resize the array if that happens.

How can i delete a UserName from a text file using Strings or io.

hi i m trainee
i have been assigned to make java program which deletes a UserName and
his Passwor from a Text File
i m unable to do it using the code below
plz help
do reply
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java .applet.*;
import java.io.*;
class Del extends JFrame implements ActionListener
     String s2;
     JTextField CWDMUserDText = new JTextField();
     JButton CWDMSecDelButton = new JButton("DELETE");
     JLabel CWDMUserLabel = new JLabel("USER NAME");
     JPasswordField CWDMPassDText = new JPasswordField();
     JLabel CWDMPassLabel = new JLabel("PASSWORD");
     //String user,pass;
     /* CONSTRUCTOR*/
          Del()
               Container contentPane=getContentPane();
               contentPane.setLayout(null);
              setLocation(400,200);
               contentPane.add(CWDMUserDText);
               contentPane.add(CWDMSecDelButton);
               contentPane.add(CWDMUserLabel);
               contentPane.add(CWDMPassDText);
               contentPane.add(CWDMPassLabel);
              CWDMUserLabel.setBounds(20,70,100,25);
              CWDMPassLabel.setBounds(20,100,100,25);
               CWDMUserDText.setBounds(150,70,100,25);
               CWDMPassDText.setBounds(150,100,100,25);
               CWDMSecDelButton.setBounds(80,135,100,25);
               CWDMUserDText.addActionListener(this);
               CWDMPassDText.addActionListener(this);
               CWDMSecDelButton.addActionListener(this);
               contentPane.setBackground(Color.CYAN);
               setVisible(true);
               setDefaultCloseOperation(EXIT_ON_CLOSE);
     public void actionPerformed(ActionEvent ae)
              if(ae.getSource()==CWDMSecDelButton)
     //             user = CWDMUserDText.getText();
     //          pass = CWDMPassDText.getText();
     //          showarr();
               s2 = CWDMUserDText.getText();
               CWDMUserDText.setText("");
               CWDMPassDText.setText("");
               DelUser(s2);
          public static void main(String args[])
               Del myframe1= new Del();
               myframe1.setSize(300,200);
               myframe1.setVisible(true);
          public void DelUser(String s)
               //int a;
               try
                    FileReader fr = new FileReader("file.txt");
                    BufferedReader br = new BufferedReader(fr);
                   String s1;
                   int a;
                   int len = s.length();
                   System.out.println(len);
                   //s2 = CWDMUserDText.getText();
                    while ((s1=br.readLine()) !=null)
                         if((a=s1.indexOf(s))>0 && (a=s1.indexOf(s))!=0)
                              System.out.println(a);
                    fr.close();
               catch(FileNotFoundException e)
                    System.out.println("exception occured");
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                    System.out.println("io");
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Some tips:
1) If you are adding or deleting stuff from a text file you need to write a new, modified file and then, optionally, do something like:
rename the old file to whatever.bak or the like.
rename the new file to the old.
2) Don't depend on System.out so much on a GUI application. For example if you get an exception use javax.swing.JOptionPane to display an alert (and show the message from the exception). You can write the stack trace to System.out if you want.
3) Don't muck about with calculating bounds for screen objects, let a layout manager sort it out. I like BoxLayoutManager for most things like this.
4) For bonus points do your IO in a separate Thread. Generally you don't want anything happening in an actionPerformed method which significantly delays it's return. The method should launch a new Thread to do the job, and disable the button until the Thread finishes.

Read data from a text file, one line at a time.

I need to read data from a text file, and display each line in a String Indicator on Front Panel. It displays each line, but I get Error 4, End Of Line, unless I enter an extra line of data in the file that I don't need. I tried Read From Text File.vi, made by Nat Instr, and it gave the same error.

The Read from Text File.vi reads data from a text file line by line until the user stops the VI manually with the Stop button on the front panel, or until an error (such as "Error 4, End of file") occurs. If an error occurs, the Simple Error Handler.vi pops up a dialog that tells you which error occurred.
The Read from Text File.vi uses a while loop, but if you knew how many lines you wanted to read, you could replace the while loop with a for loop set to read that many lines from the file.
If you need something more dynamic because the number of lines in your files vary, then you could change the code of the Read from Text File.vi to the expect "Error 4, End of file" and handle it appropriately. This would require unbundling the error cluster that comes fro
m the Read File function with the Unbundle By Name function, so that you can expose the individual error "status" and error "code" values stored in the cluster. If the value of the error "code" is 4, then you can change the error "status" from true to false, and you can rebundle the cluster with the Bundle by Name function. Setting the error "status" to false instructs the Simple Error Handler to ignore the error. Otherwise, pass the original error cluster to the Simple Error Handler.vi, so that you can see what the error is.
Of course, if you're not interested in what the errors are, you could just remove the Simple Error Handler.vi, but then you wouldn't see any error messages.
Best of Luck,
Dieter
Dieter Schweiss
Applications Engineer
National Instruments

How to read every line from a text file???

How can i read every line from my text file ("eka.txt")
now it only reads the first line and prints it out.
What is wrong with this?
import java.io.*;
import java.util.*;
class Testi{
     public static void main(String []args)throws IOException {
     BufferedReader stdin=new BufferedReader(new InputStreamReader(System.in));
File inputFile = new File ("eka.txt");
FileReader fis =new FileReader(inputFile);
BufferedReader bis = new BufferedReader(fis);
String test=bis.readLine();
String tmp= "";
while((bis.readLine().trim() != null)) {
int spacefound=0;
int l=test.indexOf(" ");
     for(int i=0;i<test.length();i++){
     char c=test.charAt(i);
     if(c!=' ') tmp+=""+c;
     if(c==' ' && (spacefound<1) && !(tmp.equals(""))){
     tmp+=""+c;
     spacefound++;
     if(tmp.length()==l) {
     System.out.println(tmp);
     tmp="";
     spacefound=0;
     if(tmp.length()<l){
     for(int i=0;i<=(l-tmp.length());i++)
     tmp+=""+' ';
     System.out.println(tmp);

Try this code, Hope it servers your purpose.
import java.io.*;
import java.util.*;
class Testi {
     public static void main(String []args)throws IOException {
          BufferedReader stdin=new BufferedReader(new InputStreamReader(System.in));
          File inputFile = new File ("Eka.txt");
          FileReader fis =new FileReader(inputFile);
          BufferedReader bis = new BufferedReader(fis);
          String test=bis.readLine();
          while(test != null) {
               StringTokenizer st = new StringTokenizer(test," ");
               while(st.hasMoreTokens())
                    System.out.println(st.nextToken());
               test = bis.readLine();
}Sudha

How to read some lines from a text file using java.

hi,
i m new to java and i want to read some lines from a text file based on some string occurrence in the file. This file to be read in steps.
we only want to read the file upto the first Occurrence of "TEXT" string.
How to do it ,,,
Kinldy give the code
Regards,
Sagar
this is the text file
dfgjdjj
sfjhjkd
ghjkdg
hjkdgh TEXT
ikeyt
ujt
jk
tyk TEXT
rukl
r

Hendawy wrote:
Since the word "TEXT" is formed of 4 letters, you would read the text file 4 bytes by four bytes. Wrong on two counts. First, the file may not be encoded 1 byte per character. It could be utf-16 in which case it would be two byte per character. Second, even if it were 1 byte per character, the string "Text" may not start on a 4 byte boundary.
Consider a FileInputStream object "fis" that points to your text file. use fis.read(byte[] array, int offset, int len) to read every four bytes. Convert the "TEXT" String into a byte array "TEXT".getBytes(), and yous the Arrays class to compare the equality of the read bytes with your "TEXT".getBytes()Wrong since it relies on my second point and will fail when fis.read(byte[] array, int offset, int len) does not read 4 bytes (as is no guaranteed to). Check the Javadoc. Also, the file may not be encoded with the default character encoding.
The problem is easily solved by reading a line at a time using a BufferedReader wrapping an InputStreamReader wrapping a FileInputStream and specifying the correct character encoding.
Edited by: sabre150 on Apr 29, 2009 2:13 PM

Delete or update a line in a text file

Hi, I've got one problem and I hope anybody can help me.
I read a text file like this :
montext = 20204578
montext2 = 22132546
montext3 = 31321321
I want to know how I can delete or update a specific line in my text file.
thanks a lot.

I read a text file like this :
montext = 20204578
montext2 = 22132546
montext3 = 31321321
I want to know how I can delete or update a specific
line in my text file.Sure. read in the file with the Readers readLine()-method in a loop; if the line it read is the one that should be removed, don't add it (or use a counter variable, if you do it by numbers) to the output String.
If it's to be replaced, replace it at that moment, then add the new line to the string.
Write back the string into the old file (don't append) and you're done.
Answer provided by Friends of the Water Cooler. Please tell forum admin via 'Discuss the JDC Web Site' forum that off-topic threads should be supported
Thanks, Geoff, good idea!

How do i read complete line from a text file in j2me?????

how do i read complete line from a text file in j2me????? I wanna read file line by line not char by char..Even i tried with readUTF of datainputstream to read word by word but i got UTFDataFormatException.. Please solve my problem.. Thanks in advance..

That is not my problem . i already read it char by char.. i am getting complete line..But this process is taking to much time..So thats why i directly wanna read complete line or word to save time..

Read specified line from a text file

Hi,
I am trying to read a specific line from a text file. I don't want to read all of it but just this specific line... say line number 2. Is there a method built-in in java or should I code this myself?
Thanks and regards,
Krt_Malta

Krt_malta wrote:
I am trying to read a specific line from a text file. I don't want to read all of it but just this specific line... say line number 2. Is there a method built-in in java or should I code this myself?Is there anything in your use case that precludes using the offset of the start of the line rather than the line number?

Search for a word and return all the lines (row) from the text file..

Hi all,
I need a help on how to search a string from the text file and returns all the lines (rows) where the searched string are found. I have included the code, it finds the indexof the string but it does not return the entire line. I would appreciate your any help.
public class SearchWord
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Hi, you can use servlet class and use this method to get the whole line of searched string. You can override the HttpServlet to treat that class as servlet.
public class ReportAction extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//write your whole logic.
BufferedReader br = new BufferedReader(new FileReader("your file name"));
String line = "";
while(line = br.readLine() != null) {
    if(line.contains("your search string")) {
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}

Deleting a line from a text file & opening a project from another project

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