HOW TO WRITE AND READ FROM A TEXT FILE???
How can I read from a text file and then display the contents in a JTextArea??????
Also how can I write the contents of a JTextArea to a text file.
Extra Question::::::: Is it possible to write records to a text file. If you have not idea what I am talking about then ignore it.
Manny thanks,
your help is much appreciated though you don't know it!
Do 3 things.
-- Look through the API at the java.io package.
-- Search previous posts for "read write from text file"
-- Search java.sun.com for information on the java.io package.
That should clear just about everything up. If you have more specific problems, feel free to come back and post them.
Similar Messages
-
How to write and read array on ObjectOutputStream............??
Hello All...........,
I have done some code for applet and servlet communication in which i writes "String " as an object and gets reply from servlet as a string as follows:
// send data to the servlet
String input="hello there.....";
URLConnection con = getServletConnection();
OutputStream outstream = con.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outstream);
oos.writeObject(input);
oos.flush();
oos.close();
// receive result from servlet
InputStream instr = con.getInputStream();
ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
String result =(String) inputFromServlet.readObject();
outputField.setText(result);
//outputField.setText("good morning");
inputFromServlet.close();
instr.close();This code is same at servlet end.
But now i want to pass an int array.How to pass int[] as an object.
It is giving me error if i pass int array as int array[]={1,2,3}; oos.writeObject(array); Why is it so?
Can anybody tell me how to write and read int array[].
Thanks.
Shraddha.hello kaj,
I am trying to write as follows
while writting:
int array[]={1,2,3,4,5};
URLConnection con = getServletConnection();
OutputStream outstream = con.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outstream);
oos.writeObject(array);
oos.flush();
oos.close();
while reading:
InputStream instr = con.getInputStream();
ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
int result[] =(int []) inputFromServlet.readObject();
Thanks,
Really imp for me. -
How to read from a text file one character at a time?
Hello
I wish to read from a text file in a for loop and that on every iteration i read one charachter and proceed to the next one.
can anyone help me?
Lavilava wrote:
I wish to read from a text file in a for loop and that on every iteration i read one charachter and proceed to the next one.
can anyone help me?
Some additional comments:
You really don't want to read any file one character at a time, because it is highly inefficient. More typically, you read the entire file into memory with one operation (or at least a large chunk, if the file is gigantic) and then do the rest of the operations in memory. One easy way to analyze it one byte at a time would be to use "string to byte array" and then autoindex into a FOR loop, for example.
Of course you could also read the file directly as a U8 array instead of a string.
Message Edited by altenbach on 06-10-2008 08:57 AM
LabVIEW Champion . Do more with less code and in less time . -
How to write and read data in a specific memory location ??
Hi Everyone:
Does anyone know how to write and read data in a specific memory location by using Java ?
I need pointers, but I don't know how to do it ??
Thanks for answering
RodgerHi Everyone:
Does anyone know how to write and read data in a
specific memory location by using Java ?
I need pointers, but I don't know how to do it ??
Thanks for answering
RodgerWith Java you cannot write to a specific memory location. Java does not have pointers. If you really want to do it, you need to use JNI, i.e write the required functions in C (or other languages that support pointers) and make those functions available to Java (through JNI). This approach is not portable. You can have a look at http://java.sun.com/docs/books/tutorial/native1.1/index.html
Regards. -
Could we write and read from a external drive using a IPad?
√could we write and read from a external drive using a IPad?
No, the iPad doesn't work that way. The only thing you can access is camera cards (with the adaptor).
Matt -
Problem with ArrayLists and writing and reading from a .dat file (I think)
I'm brand new to this forum, but I'm sure hoping someone can help me with a problem I'm having with ArrayLists. This program was originally created with an array of objects that were displayed on a GUI with jtextFields, then cycling thru them via jButtons: First, Next, Previous, Last. Now I need to add the ability to modify, delete and add records. Both iterations of this program needed to write to and read from a .dat file.
It worked just like it was suppose to when I used just the array, but now I need to use a "dynamic array" that will grow or shrink as needed: i.e. an ArrayList.
When I aded the ArrayList I had the ArrayList use toArray() to fill my original array so I could continue to use all the methods I'd created for using with my array. Now I'm getting a nullPointerException every time I try to run my program, which means somewhere I'm NOT filling my array ???? But, I'm writing just fine to my .dat file, which is confusing me to no end!
It's a long program, and I apologize for the length, but here it is. There are also 2 class files, a parent and 1 child below Inventory6. This was written in NetBeans IDE 5.5.1.
Thank you in advance for any help anyone can give me!
LabyBC
package my.Inventory6;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import javax.swing.JOptionPane;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import java.io.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.lang.IllegalStateException;
import java.util.NoSuchElementException;
import java.util.ArrayList;
import java.text.NumberFormat;
// Class Inventory6
public class Inventory6 extends javax.swing.JFrame {
private static InventoryPlusColor[] inventory;
private static ArrayList inList;
// create a tool that insure the specified format for a double number, when displayed
private DecimalFormat doubleFormat = new DecimalFormat( "0.00" );
private DecimalFormat singleFormat = new DecimalFormat( "0");
// the index within the array of products of the current displayed product
private int currentProductIndex;
/** Creates new form Inventory6 */
public Inventory6() {
initComponents();
currentProductIndex = 0;
} // end Inventory6()
private static InventoryPlusColor[] getInventory() {
ArrayList<InventoryPlusColor> inList = new ArrayList<InventoryPlusColor>();
inList.add(new InventoryPlusColor(1, "Couch", 3, 1250.00, "Blue"));
inList.add(new InventoryPlusColor(2, "Recliner", 10, 525.00, "Green"));
inList.add(new InventoryPlusColor(3, "Chair", 6, 125.00, "Mahogany"));
inList.add(new InventoryPlusColor(4, "Pedestal Table", 2, 4598.00, "Oak"));
inList.add(new InventoryPlusColor(5, "Sleeper Sofa", 4, 850.00, "Yellow"));
inList.add(new InventoryPlusColor(6, "Rocking Chair", 2, 459.00, "Tweed"));
inList.add(new InventoryPlusColor(7, "Couch", 4, 990.00, "Red"));
inList.add(new InventoryPlusColor(8, "Chair", 12, 54.00, "Pine"));
inList.add(new InventoryPlusColor(9, "Ottoman", 3, 110.00, "Black"));
inList.add(new InventoryPlusColor(10, "Chest of Drawers", 5, 598.00, "White"));
for (int j = 0; j < inList.size(); j++)
System.out.println(inList);
InventoryPlusColor[] inventory = (InventoryPlusColor[]) inList.toArray
(new InventoryPlusColor[inList.size()]);
return inventory;
} // end getInventory() method
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
// <editor-fold defaultstate="collapsed" desc=" Generated Code ">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
IDNumberLbl = new javax.swing.JLabel();
IDNumberField = new javax.swing.JTextField();
prodNameLbl = new javax.swing.JLabel();
prodNameField = new javax.swing.JTextField();
colorLbl = new javax.swing.JLabel();
colorField = new javax.swing.JTextField();
unitsInStockLbl = new javax.swing.JLabel();
unitsInStockField = new javax.swing.JTextField();
unitPriceLbl = new javax.swing.JLabel();
unitPriceField = new javax.swing.JTextField();
invenValueLbl = new javax.swing.JLabel();
invenValueField = new javax.swing.JTextField();
restockingFeeLbl = new javax.swing.JLabel();
restockingFeeField = new javax.swing.JTextField();
jbtFirst = new javax.swing.JButton();
jbtNext = new javax.swing.JButton();
jbtPrevious = new javax.swing.JButton();
jbtLast = new javax.swing.JButton();
jbtAdd = new javax.swing.JButton();
jbtDelete = new javax.swing.JButton();
jbtModify = new javax.swing.JButton();
jbtSave = new javax.swing.JButton();
jPanel2 = new javax.swing.JPanel();
searchIDNumLbl = new javax.swing.JLabel();
searchIDNumbField = new javax.swing.JTextField();
jbtSearch = new javax.swing.JButton();
searchResults = new javax.swing.JLabel();
jbtExit = new javax.swing.JButton();
jbtExitwoSave = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Inventory Program"));
IDNumberLbl.setText("ID Number");
IDNumberField.setEditable(false);
prodNameLbl.setText("Product Name");
prodNameField.setEditable(false);
colorLbl.setText("Product Color");
colorField.setEditable(false);
colorField.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
colorFieldActionPerformed(evt);
unitsInStockLbl.setText("Units In Stock");
unitsInStockField.setEditable(false);
unitPriceLbl.setText("Unit Price $");
unitPriceField.setEditable(false);
invenValueLbl.setText("Inventory Value $");
invenValueField.setEditable(false);
restockingFeeLbl.setText("5% Restocking Fee $");
restockingFeeField.setEditable(false);
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(unitPriceLbl)
.addComponent(unitsInStockLbl)
.addComponent(colorLbl)
.addComponent(prodNameLbl)
.addComponent(IDNumberLbl)
.addComponent(restockingFeeLbl)
.addComponent(invenValueLbl))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(IDNumberField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(prodNameField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(colorField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(unitsInStockField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(unitPriceField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(restockingFeeField, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE)
.addComponent(invenValueField, javax.swing.GroupLayout.DEFAULT_SIZE, 176, Short.MAX_VALUE))
.addContainerGap())
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(IDNumberLbl)
.addComponent(IDNumberField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(prodNameLbl)
.addComponent(prodNameField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(colorField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(colorLbl))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(unitsInStockField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(unitsInStockLbl))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(unitPriceField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(unitPriceLbl))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(restockingFeeField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(restockingFeeLbl))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 10, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(invenValueField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(invenValueLbl))
.addContainerGap())
jbtFirst.setText("First");
jbtFirst.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtFirstActionPerformed(evt);
jbtNext.setText("Next");
jbtNext.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtNextActionPerformed(evt);
jbtPrevious.setText("Previous");
jbtPrevious.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtPreviousActionPerformed(evt);
jbtLast.setText("Last");
jbtLast.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtLastActionPerformed(evt);
jbtAdd.setText("Add");
jbtAdd.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtAddActionPerformed(evt);
jbtDelete.setText("Delete");
jbtModify.setText("Modify");
jbtModify.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtModifyActionPerformed(evt);
jbtSave.setText("Save");
jbtSave.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtSaveActionPerformed(evt);
jPanel2.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Search by:"));
searchIDNumLbl.setText("Item Number:");
jbtSearch.setText("Search");
searchResults.setFont(new java.awt.Font("Tahoma", 1, 12));
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addContainerGap()
.addComponent(searchIDNumLbl)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(259, 259, 259)
.addComponent(searchResults, javax.swing.GroupLayout.PREFERRED_SIZE, 213, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jbtSearch, javax.swing.GroupLayout.PREFERRED_SIZE, 83, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(searchIDNumbField, javax.swing.GroupLayout.PREFERRED_SIZE, 143, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(searchIDNumLbl)
.addComponent(searchIDNumbField, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(32, 32, 32)
.addComponent(searchResults, javax.swing.GroupLayout.PREFERRED_SIZE, 17, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(jPanel2Layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtSearch)))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
jbtExit.setText("Save and Exit");
jbtExit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtExitActionPerformed(evt);
jbtExitwoSave.setText("Exit");
jbtExitwoSave.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jbtExitwoSaveActionPerformed(evt);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, 248, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 44, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(jbtExitwoSave, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jbtExit)))
.addGroup(layout.createSequentialGroup()
.addComponent(jbtFirst)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtNext)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtPrevious)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtLast))
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGap(12, 12, 12)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jbtAdd)
.addComponent(jbtDelete)
.addComponent(jbtModify)
.addComponent(jbtSave))))
.addContainerGap())
layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {jbtFirst, jbtLast, jbtNext, jbtPrevious});
layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {jbtAdd, jbtDelete, jbtModify, jbtSave});
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(21, 21, 21)
.addComponent(jbtAdd)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtDelete)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtModify)
.addGap(39, 39, 39)
.addComponent(jbtSave))
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jbtFirst)
.addComponent(jbtNext)
.addComponent(jbtPrevious)
.addComponent(jbtLast))
.addGap(15, 15, 15)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, 80, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createSequentialGroup()
.addComponent(jbtExit)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jbtExitwoSave)))
.addContainerGap())
pack();
}// </editor-fold>
private void jbtExitwoSaveActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
private void jbtSaveActionPerformed(java.awt.event.ActionEvent evt) {
String prodNameMod, colorMod;
double unitsInStockMod, unitPriceMod;
int idNumMod;
idNumMod = Integer.parseInt(IDNumberField.getText());
prodNameMod = prodNameField.getText();
unitsInStockMod = Double.parseDouble(unitsInStockField.getText());
unitPriceMod = Double.parseDouble(unitPriceField.getText());
colorMod = colorField.getText();
if(currentProductIndex == inventory.length) {
inList.add(new InventoryPlusColor(idNumMod, prodNameMod,
unitsInStockMod, unitPriceMod, colorMod));
InventoryPlusColor[] inventory = (InventoryPlusColor[]) inList.toArray
(new InventoryPlusColor[inList.size()]);
} else {
inventory[currentProductIndex].setIDNumber(idNumMod);
inventory[currentProductIndex].setProdName(prodNameMod);
inventory[currentProductIndex].setUnitsInStock(unitsInStockMod);
inventory[currentProductIndex].setUnitPrice(unitPriceMod);
inventory[currentProductIndex].setColor(colorMod);
displayProduct(inventory[currentProductIndex]);
private static void writeInventory(InventoryPlusColor i,
DataOutputStream out) {
try {
out.writeInt(i.getIDNumber());
out.writeUTF(i.getProdName());
out.writeDouble(i.getUnitsInStock());
out.writeDouble(i.getUnitPrice());
out.writeUTF(i.getColor());
} catch (IOException e) {
JOptionPane.showMessageDialog(null, "I/O Exception writing data",
"", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} //end writeInventory()
private static DataOutputStream openOutputStream(String name) {
DataOutputStream out = null;
try {
File file = new File(name);
out =
new DataOutputStream(
new BufferedOutputStream(
new FileOutputStream(file)));
} catch (IOException e) {
JOptionPane.showMessageDialog(null, "I/O Error", "", JOptionPane.ERROR_MESSAGE);
System.exit(0);
return out;
} // end openOutputStream()
private static void closeFile(DataOutputStream out) {
try {
out.close();
} catch (IOException e) {
JOptionPane.showMessageDialog(null, "I/O Exception closing file",
"", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end closeFile()
private static DataInputStream getStream(String name) {
DataInputStream in = null;
try {
File file = new File(name);
in = new DataInputStream(
new BufferedInputStream(
new FileInputStream(file)));
} catch (FileNotFoundException e) {
JOptionPane.showMessageDialog(null, "The file doesn't exist",
"", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} catch (IOException e) {
JOptionPane.showMessageDialog(null, "I/O Error creating file",
"", JOptionPane.ERROR_MESSAGE);
System.exit(0);
return in;
private static void closeInputFile(DataInputStream in) {
try {
in.close();
} catch (IOException e) {
JOptionPane.showMessageDialog(null, "I/O Exception closing file",
"", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end closeInputFile()
private double entireInventory() {
// a temporary double variable that the method will return ...
// after each product's inventory is added to it
double entireInventory = 0;
// loop to control number of products
for (int index = 0; index < inventory.length; index++) {
// add each inventory to the entire inventory
entireInventory += inventory[index].setInventoryValue();
} // end loop to control number of products
return entireInventory;
} // end method entireInventory
private void jbtLastActionPerformed(java.awt.event.ActionEvent evt) {
currentProductIndex = inventory.length-1; // move to the last product
// display the information for the last product
displayProduct(inventory[currentProductIndex]);
private void jbtPreviousActionPerformed(java.awt.event.ActionEvent evt) {
if (currentProductIndex != 0) // it's not the first product displayed
currentProductIndex -- ; // move to the previous product (decrement the current index)
} else // the first product is displayed
currentProductIndex = inventory.length-1; // move to the last product
// after the current product index is set, display the information for that product
displayProduct(inventory[currentProductIndex]);
private void jbtNextActionPerformed(java.awt.event.ActionEvent evt) {
if (currentProductIndex != inventory.length-1) // it's not the last product displayed
currentProductIndex ++ ; // move to the next product (increment the current index)
} else // the last product is displayed
currentProductIndex = 0; // move to the first product
// after the current product index is set, display the information for that product
displayProduct(inventory[currentProductIndex]);
private void jbtFirstActionPerformed(java.awt.event.ActionEvent evt) {
currentProductIndex = 0;
// display the information for the first product
displayProduct(inventory[currentProductIndex]);
private void colorFieldActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
private void jbtModifyActionPerformed(java.awt.event.ActionEvent evt) {
prodNameField.setEditable(true);
prodNameField.setFocusable(true);
unitsInStockField.setEditable(true);
unitPriceField.setEditable(true);
private void jbtAddActionPerformed(java.awt.event.ActionEvent evt) {
IDNumberField.setText("");
IDNumberField.setEditable(true);
prodNameField.setText("");
prodNameField.setEditable(true);
colorField.setText("");
colorField.setEditable(true);
unitsInStockField.setText("");
unitsInStockField.setEditable(true);
unitPriceField.setText("");
unitPriceField.setEditable(true);
restockingFeeField.setText("");
invenValueField.setText("");
currentProductIndex = inventory.length;
private void jbtExitActionPerformed(java.awt.event.ActionEvent evt) {
DataOutputStream out = openOutputStream("inventory.dat");
for (InventoryPlusColor i : inventory)
writeInventory(i, out);
closeFile(out);
System.exit(0);
private static InventoryPlusColor readProduct(DataInputStream in) {
int idNum = 0;
String prodName = "";
double inStock = 0.0;
double pricBalusC -- The line that gives me my NullPointerException is when I call the "DisplayProduct()" method. Its a dumb question, but with NetBeans how do I find out which reference could be null? I'm not very familiar with how NetBeans works with finding out how to debug. Any help you can give me would be greatly appreciated.The IDE is com-plete-ly irrelevant. It's all about the source code.
Do you understand anyway when and why a NullPointerException is been thrown? It is a subclass of RuntimeException and those kind of exceptions are very trival and generally indicate an design/logic/thinking fault in your code.
SomeObject someObject = null; // The someObject reference is null.
someObject.doSomething(); // Invoking a reference which is null would throw NPE. -
Reading from a text file into a 2D array
How do you read from a text file and put it into a 2D array? Or if someone could guide me to where I can find the information?
This tutorial shows how to read a file:
http://java.sun.com/docs/books/tutorial/essential/io/scanfor.html
This tutorial shows how to create arrays with multiple dimensions:
http://java.sun.com/docs/books/tutorial/java/nutsandbolts/arrays.html -
Getting repeated values when reading from a text file.
I need to read from a text file. When the token encounters a particular word (command) I need to read the next line and perform some actions. However, this part is working but it is repeating the values again and again until it encounters the next particular word (command). Hope that someone will help me out, as always when I posted a problem in these forums.
SetOperations class - contains the set methods
// Imported packages.========================================================
import java.util.Vector;
import java.util.Iterator;
// Public class SetOperations.===============================================
public class SetOperations
// Instance variables.===================================================
private Vector v = null; // Creates new instance of vector.
protected int memberCount;
// Constructor.==========================================================
public SetOperations()
v = new Vector();
} // end constructor.
// Method isMember.======================================================
* Checks whether the element is already a member of the set.
* @return True if Vector v contains Object member.
public boolean isMember(Object member)
if (member != null) // only if Object member is not null.
return v.contains(member); // returns true if vector already contains member.
else
return false; // returns false if vector does not contain member.
} // end public boolean isMember(Object member).
// Method addMember.=====================================================
* Adds a member to the set.
* @return Adds Object member to Vector v.
public void addMember(Object member)
//if (! v.contains(member)) // only if element is not already a member.
if (isMember(member) == false) // only if element is not already a member.
v.add(member); // adds a member.
} // end public void addMember(Object member).
// Method countMember.===================================================
* Returns the number of members present in the vector.
* @return Number of elements present in the vector.
public int countMember()
return v.size();
} // end public int countMember().
// Method isSetEmpty.====================================================
* Returns true if set is empty.
* @return True if no elements are present in Vector v.
public boolean isSetEmpty()
return v.size() == 0; // returns 0 if no elements are present in the vector.
} // end of public boolean isSetEmpty().
// Method printMember.===================================================
* Displays member/s of the set.
* @return Prints element/s present in the vector.
public void printMember()
for (int i = 0; i < v.size(); i++) // iterates through present members.
System.out.println("[" + i + "] " + v.get(i)); // displays member/s present in the vector.
} // end of public void printMember().
} // end public class SetOperations.
SetTextLauncher class - reads from a text file and implements the set operations
// Imported packages.========================================================
import java.util.*;
import java.io.*;
// Public class SetTestLauncher.=============================================
public class SetTestLauncher
// Main method public static void main(String args[]).===================
public static void main(String args[])
displayFile("test.txt"); // outputs result from text file.
// method to display a file on screen
public static void displayFile (String textFile)
// Instance variables.===============================================
// Creates new instances of SetOperations.
SetOperations setA = new SetOperations();
SetOperations setB = new SetOperations();
SetOperations setC = new SetOperations();
SetOperations setD = new SetOperations();
SetOperations setE = new SetOperations();
// Initialisation.
String line = "", nextLine = "";
FileReader fr = null;
try
// Opens the file with the FileReader data sink stream.
fr = new FileReader(textFile);
// Converts the FileReader input stream with the BufferedReader processing stream.
BufferedReader br = new BufferedReader(fr);
// Iterates through text file reading lines until end of text lines.
while (line != null)
line = br.readLine(); // reads one line at a time.
if(line == null) break; // when the line is null break the loop.
// Creates a new instace of StringTokenizer.
StringTokenizer st = new StringTokenizer(line);
// Loops until there are no more tokens.
while (st.hasMoreTokens())
String token = st.nextToken(); // reads next token.
// Only if the token encounters the String "membera".
if(token.equals("membera"))
nextLine = br.readLine(); // gets next line.
setA.addMember(nextLine); // adds a member to the set.
// Displays members present in the set if vector is not empty.
if (! setA.isSetEmpty())
setA.printMember(); // print members present.
// Displays the number of member/s present in the vector.
System.out.println("Number of set members: " + setA.countMember());
// Catches and displays exceptions.
catch (FileNotFoundException exp)
System.out.println(exp.getMessage());
exp.printStackTrace();
catch (IOException exp)
System.out.println(exp.getMessage());
exp.printStackTrace();
finally
try
// if file is found
if (fr != null)
// close file
fr.close();
catch (IOException exp)
exp.printStackTrace();
} // end public static void main(String args[]).
} // end public class SetTestLauncher.Thanks for your interest. Please ignore SetOperations class, it is just the class containing the methods and it works correctly since I checked it without reading from a text file. I marked the part where I think lies my problem in class SetTestOperations.
The information in the text file is as follows:
membera
Hillman
membera
Skoda
membera
Honda
membera
Toyota
and the result is:
[0] Hillman
Number of set members: 1
[0] Hillman
[1] Skoda
Number of set members: 2
[0] Hillman
[1] Skoda
[2] Honda
Number of set members: 3
[0] Hillman
[1] Skoda
[2] Honda
[3] Toyota
Number of set members: 4
instead of just one set:
[0] Hillman
[1] Skoda
[2] Honda
[3] Toyota
Number of set members: 4
Hope it is easier to understand like this.
Regards
Marco
I need to read from a text file. When the token
encounters a particular word (command) I need to read
the next line and perform some actions. However, this
part is working but it is repeating the values again
and again until it encounters the next particular
word (command). Hope that someone will help me out,
as always when I posted a problem in these forums.
SetOperations class - contains the set
methods
// Imported
packages.=============================================
===========
import java.util.Vector;
import java.util.Iterator;
// Public class
SetOperations.========================================
=======
public class SetOperations
// Instance
e
variables.============================================
=======
private Vector v = null; // Creates new instance of
f vector.
protected int memberCount;
Constructor.==========================================
================
public SetOperations()
v = new Vector();
} // end constructor.
// Method
d
isMember.=============================================
=========
* Checks whether the element is already a member of
f the set.
* @return True if Vector v contains Object member.
public boolean isMember(Object member)
if (member != null) // only if Object member is not
ot null.
return v.contains(member); // returns true if
if vector already contains member.
else
return false; // returns false if vector does not
not contain member.
} // end public boolean isMember(Object member).
// Method
d
addMember.============================================
=========
* Adds a member to the set.
* @return Adds Object member to Vector v.
public void addMember(Object member)
//if (! v.contains(member)) // only if element is
is not already a member.
if (isMember(member) == false) // only if element
nt is not already a member.
v.add(member); // adds a member.
} // end public void addMember(Object member).
// Method
d
countMember.==========================================
=========
* Returns the number of members present in the
e vector.
* @return Number of elements present in the vector.
public int countMember()
return v.size();
} // end public int countMember().
// Method
d
isSetEmpty.===========================================
=========
* Returns true if set is empty.
* @return True if no elements are present in Vector
r v.
public boolean isSetEmpty()
return v.size() == 0; // returns 0 if no elements
ts are present in the vector.
} // end of public boolean isSetEmpty().
// Method
d
printMember.==========================================
=========
* Displays member/s of the set.
* @return Prints element/s present in the vector.
public void printMember()
for (int i = 0; i < v.size(); i++) // iterates
es through present members.
System.out.println("[" + i + "] " + v.get(i)); //
// displays member/s present in the vector.
} // end of public void printMember().
} // end public class SetOperations.
SetTextLauncher class - reads from a text file
and implements the set operations
// Imported
packages.=============================================
===========
import java.util.*;
import java.io.*;
// Public class
SetTestLauncher.======================================
=======
public class SetTestLauncher
// Main method public static void main(String
g args[]).===================
public static void main(String args[])
displayFile("test.txt"); // outputs result from
om text file.
// method to display a file on screen
public static void displayFile (String textFile)
// Instance
ce
variables.============================================
===
// Creates new instances of SetOperations.
SetOperations setA = new SetOperations();
// Initialisation.
String line = "", nextLine = "";
FileReader fr = null;
try
// Opens the file with the FileReader data sink
ink stream.
fr = new FileReader(textFile);
// Converts the FileReader input stream with the
the BufferedReader processing stream.
BufferedReader br = new BufferedReader(fr);
// Iterates through text file reading lines until
til end of text lines.
while (line != null)
line = br.readLine(); // reads one line at a
at a time.
if(line == null) break; // when the line is null
null break the loop.
// Creates a new instace of StringTokenizer.
StringTokenizer st = new StringTokenizer(line);
// Loops until there are no more tokens.
while (st.hasMoreTokens())
String token = st.nextToken(); // reads next
next token.
// Only if the token encounters the String
tring "membera".
if(token.equals("membera"))
// *****THE PROBLEM LIES HERE....I GUESS
// need to read the next line after encountering the word membera in text file
nextLine = br.readLine(); // gets next line.
setA.addMember(nextLine); // adds a member to
ber to the set.
// Displays members present in the set if
set if vector is not empty.
if (! setA.isSetEmpty())
setA.printMember(); // print members present.
// Displays the number of member/s present in
ent in the vector.
System.out.println("Number of set members: " +
s: " + setA.countMember());
// Catches and displays exceptions.
catch (FileNotFoundException exp)
System.out.println(exp.getMessage());
exp.printStackTrace();
catch (IOException exp)
System.out.println(exp.getMessage());
exp.printStackTrace();
finally
try
// if file is found
if (fr != null)
// close file
fr.close();
catch (IOException exp)
exp.printStackTrace();
} // end public static void main(String args[]).
} // end public class SetTestLauncher. -
I would like to plott data from a text file in the same way as a media player does from a video file. I’m not sure how to create the pointer slide function. The vi could look something like the attached jpg.
Please, can some one help me?
Martin
Attachments:
Plotting from a text file like a media player example.jpg 61 KBHI Martin,
i am not realy sure what you want!?!?
i think you want to display only a part of the values you read from XYZ
so what you can do:
write all the values in an array.
the size of the array is the max. value of the slide bar
now you can select a part of the array (e.g. values from 100 to 200) and display this with a graph
the other option is to use the history function of the graphes
regards
timo -
Reading from a text file and displaying the contents with in a frame
Hi All,
I am trying to read some data from a text file and display it on a AWT Frame. The contents of the text file are as follows:
pcode1,pname1,price1,sname1,
pcode2,pname2,price2,sname1,
I am writing a method to read the contents from a text file and store them into a string by using FileInputStream and InputStreamReader.
Now I am dividing the string(which has the contents of the text file) into tokens using the StringTokenizer class. The method is as show below
void ReadTextFile()
FileInputStream fis=new FileInputStream(new File("nieman.txt"));
InputStreamReader isr=new InputStreamReader(fis);
char[] buf=new char[1024];
isr.read(buf,0,1024);
fstr=new String(buf);
String Tokenizer st=new StringTokenizer(fstr,",");
while(st.hasMoreTokens())
pcode1=st.nextToken();
pname1=st.nextToken();
price1=st.nextToken();
sname1=st.nextToken();
} //close of while loop
} //close of methodHere goes my problem: I am unable to display the values of pcode1,pname1,price1,sname1 when I am trying to access them from outside the ReadTextFile method as they are storing "null" values . I want to create a persistent string variable so that I can access the contents of the string variable from anywhere with in the java file. Please provide your comments for this problem as early as possible.
Thanks in advance.If pcode1,pname1,price1,sname1 are global variables, which I assume they are, then simply put the word static in front of them. That way, any class in your file can access those values by simply using this notation:
MyClassName.pcode1;
MyClassName.pname1;
MyClassName.price1;
MyClassName.sname1 -
How to write and read Japanese on my Nokia E5
I am trying to find out how I can write and read Japanese on my Nokia E5.
I even don't knwo if it's possible...
Does anyone have the answer???Hello ikokitakun,
I believe you have to load a version of software on your phone that has the Japanese language pack in it because the version of software on the phone only has the languages for the region that you bought the phone in. for example if i bought my phone in NZ it would have English, Malaysian and maybe Philippino. There are "dodgey" places you can go to get the software changed but if you do this you void your warranty so be careful. Nokia doesn't condone the changing of regional software.
Hope this helps
-Cheers
"Freedom is the only way, yeah!" -
How do i split content from the text file using tab and spaces...?
Hi.. Just want to ask help to all the experts. Im new in java and i have this problem on how to split the contents of the text file. ill show you the contents in order to let you see what i mean.
FileName: COL.txt
AcctNo AcctName Primary Secondary Status Opendate
121244 IPI Company Noel Jose Active 12/05/2007
As you can see the content i want to split it per column.. Please help meJose_Noel wrote:
Hi prometheuzz,
What do you mean by one thread...?You created two threads* with the same question in it. That way, people might end up giving you an answer that has already been posted in your other thread: thus wasting that person's time.
Just don't create multiple threads with the same question please.
* a thread is a post here at the forum -
Reading from a text file in to an array, help please
I have the following
public class date extends Loans{
public int dd;
public int mm;
public int yyyy;
public String toString() {
return String.format( "%d,%d,%d", mm, dd, yyyy );
public class Loans extends Borrowing {
public String name;
public String book;
public date issue;
public char type;
public String toString(){
return String.format( "%s, %s, %s, %s", name, book, issue, type );
import java.util.Scanner;
import java.io.*;
public class Borrowing extends BorrowingList {
private Loans[] Loaned = new Loans[20];
if i want to read in from a text file in to that array how do i do it?sorry to keep bothering you and thanks loads for your help but now I am getting the following error mesage
C:\Documents and Settings\MrW\Menu.java:43: cannot find symbol
symbol : class IOException
location: class Menu
}catch(IOException e){
Note: C:\Documents and Settings\MrW\Borrowing.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error
BUILD FAILED (total time: 0 seconds)
for this line
}catch(IOException e){ -
How to load Test data from a Text file in ECATT
Hi,
I have created a test configuration with a test script, system data container, and test data container.
I have done the recording of a transaction and created the script. Parameterization is done for the script and have imported those parameters from script in to the data container.
I am trying to load a the data from a text file on the local work-station. The data is not being read.
Please explain this in detail (step by step) as I am very new to ECATT.
I am trying this on SAP ECC 6.0 IDES server.
Thanks in Advance
Vikas PatilPlease explain this in detail (step by step) as I am very new to ECATT.
Thanks in Advance
Vikas Patil -
How to load SQL scripts from a text file.
Hi, i tried several time to load a text file/SQL script with 10 different tables and data, but 10g Express doesen't allows me to do that, any one can direct me or point out to me what i should do or do i need to adopt any special method to to get this done. i am sure there must be some thing where you can upload SQL scripts from a text file (in SQL command editor!). thanks
Hi,
see my other answer here:
SQL command editor doesn't take more than 1 insert command
This seems to be a duplicate question, right? Or am I missing something?
Regards,
~Dietmar.
Maybe you are looking for
-
Logic 9.01 / Snow Leopard / problems with Sonata-font !
Is anybody here working with the adobe sonata score-font on Logic 9.01 and SL ? Since I updated to 9.01 and OSX 10.61 I cannot not use it anymore - everytime i open the score-editor the CPU-usage goes up to 100% and Logic freezes when clicking inside
-
Badi ME_PROCESS_REQ_CUST Sample Code required for changing the values
Dear Friends, I am new to the Badi technology. We would like to populate/change the standard field values, (Purchasing group) during Purchase Requisition creation/change. Method --> PROCESS_ITEM. I tried the following code, but system blnaks out all
-
Use of foreign key check in ABAP reports
Hi, I'm trying to understand if it's possible to use a foreign key integrity check in an ABAP reports. I have understood that this kind of check is deactivated for performance reasons, is it right? In this case I'd like to know if it is possible to a
-
Error Sending Mail Using FM 'SO_NEW_DOCUMENT_ATT_SEND_API1'
Dear All, I am calling the function module 'SO_NEW_DOCUMENT_ATT_SEND_API1' inside the program to send mail to ( i.e [email protected]) either yahoo or gmail or etc. After calling this function module i am getting error message ''Document could no
-
My imovie keeps on qutting whenever i add something to the movie or try to export it. When i press reopen it does the same thing again. i updated my software just now. what should i do? Process: iMovie [271] Path: /Applications/iMo