PrintWriter Using FileWriter As Parameter
Oct 24, 2014
How to write a new file:
import acm.program.*;
import java.io.*;
import java.io.PrintWriter.*;
import acm.util.*;
import javax.swing.*;
public class PrintWriter extends ConsoleProgram {
public void run() {
try {
PrintWriter wr = new PrintWriter( new FileWriter ("hello.txt") ) ;
wr.println("Hello world!");
wr.close();
} catch (IOException er) {
println("File could not be saved.");
}
}
}
(I added the imports at top myself.) However, I am getting compiler errors for the lines: PrintWriter wr = new PrintWriter( new FileWriter ("hello.txt") ) , which says that the constructor PrintWriter( FileWriter ) is undefined, and
wr.close();, which says close() method is undefined.
Pretty sure the only real problem is that PrintWriter is not accepting the FileWriter as constructor, but I don't see why. I have tried this on machine with JRE 1.4 and it worked as expected, creating new file titled "hello.txt", prints line of "Hello world!" in that file, and saves it to the directory I picked in the dialog. But I can't get it to work on this machine that uses Compiler 1.6, Java Runtime v8u25.
I have also tried using just a string in the parameter for PrintWriter, such as PrintWriter wr = new PrintWriter ("hello.txt") , and from what I can tell by reading the java spec for java 8, this should work. [URL] .... But I get error message for that constructor as well.
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Jul 12, 2014
I want to read in a text file(list of Names) using FileReader than Write to another file using FileWriter. Using FileWriter, I only want to write the Name starting with F to a new text file. I have the file reading from one text than writing to another text. The tricky part is filtering the names starting with only F.
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Mar 23, 2015
I am trying to write a hashset to a text file. Normally, I have no issues with writing to txt as it is simple for me. However, in this case I am absolutely clueless.
A bit of background about the class: it is a hashset of ComputerScientist objects with 2 fields; name, and field of research (and yes, I know what I put to fill up the HashSet does not count, I was only trying to test to see if I could get this to work).
I know the basic setup to use filewriter to save strings to a txt, but I am getting confused with the HashSet element of it.
import java.util.HashSet;
import java.io.FileWriter;
import java.io.IOException;
/**
* Write a description of class ComputerScientistSet here.
*/
public class ComputerScientistSet {
private HashSet<ComputerScientist> computerScientistSet;
[Code] .....
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Apr 27, 2014
Ive been trying to implement the Filewriter to my code. What I want is to have the textfield data written to a text field. Im thinking you have to specify the text field you want to have in the filewriter statement,I've done something like this, Ive used the try catch block.
if (source == jBPay) {
System.out.println("Pay");
{
double dOrderTotal = dTotal*1.2;
jTTotal.setText(Double.toString(dOrderTotal));
jTTotal.setHorizontalAlignment(JTextField.CENTER); // align text field centre
jTotal.setText(String.format("%.2f", dTotal)); // set pay text field to 2 decimal place
[code]...
What I want is to have the textfield data written to a text file*Hi all, Ive been trying to implement the Filewriter to my code but I cant figure out what im doing wrong.What I want is to have the file data written to a text field. Im thinking you have to specify the text field you want to have in the filewriter statement.
if (source == jBPay) {
System.out.println("Pay");
{
double dOrderTotal = dTotal*1.2;
[code]...
how do I delete a double comment?
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Oct 10, 2014
I am having an issue with using FileWriter to print some text to a text file. In the following code, I am supposed to be able to print the initial attributes and the user changed inputs into a file but all I am getting is the memory locations of the objects I created in one long line.
package project3final;
import java.io.*;
import java.util.*;
public class Project3Final {
static class Instrument {
char [] stringNames = {'E', 'A', 'D', 'G', 'B', 'E'};
private final String instrumentName;
[Code] ....
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Jun 7, 2014
I am having a bit of difficulty understanding/Using FileWriter. Now by my understanding in the API FileWriter allows to use write at the end of your file, if you have text in there already, correct?
I have a file with people info in it. And I created a GUI which allows people to input that data.
Java Code:
File file = new File("People.txt");
FileWriter fw = new FileWriter(file);
People p = new People(firstName, lastName, email, sex));
fw.append(p);
fw.close() mh_sh_highlight_all('java');
Now, I keep getting an error on the fw.append(p)
Java Code:
The method append(CharSequence) in the type Writer is not applicable for the arguments(People) mh_sh_highlight_all('java');
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Apr 2, 2014
I am using netbeans to create a hotel booking system, just tessting out code to get the booking information input to a file when the next button is clicked.
File file = new File("file.txt");
try (BufferedWriter br = new BufferedWriter(new FileWriter(file))) {
br.write("################################");
br.newLine();
br.write(" Booking Information");
br.newLine();
br.newLine();;
br.write("First Name: " + TxtName.getText());
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
Nothing is getting wrote to the file though. Does that code seem right?
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Oct 10, 2014
I am having an issue with using FileWriter to print some text to a text file. In the following code, I am supposed to be able to print the initial attributes and the user changed inputs into a file but all I am getting is the memory locations of the objects I created in one long line.
package project3final;
import java.io.*;
import java.util.*;
public class Project3Final {
static class Instrument {
char [] stringNames = {'E', 'A', 'D', 'G', 'B', 'E'};
private final String instrumentName;
[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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Dec 6, 2014
I'm tyring to print the same output in console to a text file, but I can only get the last line of the console output in the text file, not sure what is wrong with my code:
while (in.hasNextLine()) {
PrintWriter writer = new PrintWriter("output5.txt");
tempS = in.nextLine().toLowerCase();
System.out.println(wp.bestPages(tempS));
[code]....
What's causing only the last time to be printed in text file? Are there better ways to print console outputs into a text file than PrintWriter?
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Apr 12, 2014
I've written a simple html/servlet program that has a user enter their name and password on a form and then either register or login using a submit button. I have the program working, except when a user doesn't fill in either of the text fields I can't figure out how to get it to print to the page. Right now I just have it printing to my Eclipse console which is not what I want. What am I missing?
HTML code:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Cookies</title>
[code]....
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Nov 9, 2014
i've got this code that i cant get to work as i want it to. when its exported and i run it the file i wants gets created but when i open the file there is a single number like 999998000001
import java.io.IOException;
import java.io.PrintWriter;
public class mainHej {
public static void main(String arg[]){
[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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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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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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Dec 8, 2014
I have done lots of PrintWriting before but this is the first time I have done it on my new computer and I'm having an error I haven't seen before. This is my code:
Rprint(){
try {
PrintWriter pout = new PrintWriter(new FileWriter("C:UsersJackDocumentsexample.r "));
pout.println("nums = c(1,2,5,6,8,10)");
pout.println("nums");
pout.close();
} catch (IOException ex) {
System.out.println("Error!");
Logger.getLogger(Rprint.class.getName()).log(Level .SEVERE, null, ex);
}
}
*** java.io.FileNotFoundException: C:UsersJackDocuments
This.txt (The filename, directory name or volume label syntax is incorrect) ***
I have a feeling it may be to do with permissions, because it lets me print simply ("example.r") into my project folder.
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Jun 30, 2014
Write a program that asks the user for the names of two files. The first file should be opened for reading and the second file should be opened for writing. Ihe program should read the contents of the first file, change all characters to uppercase, and store the results in the second file. The second file will be a copy of the first file, except that all the characters w ill be uppercase. Use Notepad or another text editor to create a simple file that can be used to test the program
Here is my code. I Also made two text document files that are located in the same directory as the .class file (the code file) that are named OriginalFile and UpperCase respectively. Please let me know what I need to do. Here is the code.
import java.util.Scanner;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
public class UpperCaseFile
{
public static void main (String [] args) throws IOException
{
[Code]...
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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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Jun 13, 2014
Does printwriter always truncates the existing file to 0 size before adding any new data ??
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Apr 19, 2014
I was practicing my java skills and came across an exercise in which a non parameter constructor calls a two parameter constructor. I tried a few searches online but they all came back unsuccessful. This is the part I am working on:
public PairOfDice(int val1, int val2) {
// Constructor. Creates a pair of dice that
// are initially showing the values val1 and val2.
die1 = val1; // Assign specified values
die2 = val2; // to the instance variables.
}
public PairOfDice() {
// Constructor that calls two parameter constructor
}
I tried calling the two constructor using the line "this(val1, val2)" but I get an error because val1 and val2 are local variables.
Then I tried to use the same signature: "this(int val1, int val2)" but that didn't work either.
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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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Mar 30, 2014
I'm displaying a 3-column table with the column names ID, name, and salary. I made the ID into a link to go to the EditServlet class. What I'm trying to do is figure out which ID# was clicked to get onto the servlet page, how to implement that dynamically?
I know that if you put something like ?x=1 and then getParameter("x") on the servlet page would work, but then all the IDs would have the same parameters since I'm using a for loop to print out my ArrayList of objects.
My code for the jsp part is below.
for (int count=0; count<list.size(); count++) {
%>
<tr>
<td> <a href="EditServlet"><%= list.get(count).id %></a>
<td> <%= list.get(count).name %>
[Code] ....
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Apr 30, 2014
I'm using Java in BlueJ where I'm trying to write a class to store cycling club membership details in a map. I'm trying to pass a map as a parameter to a function that will iterate over the map and print out the member details. My code is:
public class CtcMembers
{
//instance variables
private Map<String, Set<String>> memberMap;
/**
* Constructor for objects of class CtcMembers
[Code] ....
When I execute the following in the OU workspace:
CtcMembers c = new CtcMembers();
c.addCyclists();
I can see a map populated with the expected details.
When I execute the following in the OU workspace:
c.printMap(c.getMap());
I get the following error:
java.lang.ClassCastException: java.util.HashSet cannot be cast to java.lang.String
in CtcMembers.printMap(CtcMembers.java:81)
in (OUWorkspace:1)
I wasn't aware I was trying to cast anything so this has got me baffled.
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May 18, 2014
I am trying to create a method called getVariable will has a parameter of a variable that has a type of Test, an enumeration. An int variable called x is assigned a value of 5, and through control statements, I want its value to change depending on what the argument is. I was able to correctly create this method, but when I use it I get an error saying, "non static method getVariable(Test) cannot be referenced from a static context" on line 28.
Here is the code:
package javaapplication5;
public class Product implements Cloneable
{
[Code].....
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Mar 11, 2015
I have a entry in application.properties file
caption_bubble_value.title={0} is a caption for the element box
JSP File
<fmt:message key="caption_bubble_value.title" />
in the java file I am setting a parameter to session
request.getSession().setAttribute("replaceVal", "Value headline");
How can I get the text "Value headline is a caption for the element box" on the page?
The replacement should happen on an event.
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Aug 8, 2014
i want to pass an object of type Software to assign it to a computer from Computer class...
i should note that computer and software are arrays of objects thats the variable and method to set software in Computer class
private Software[] software;
public void setSoftware(Software software,int index){
this.software[index]=software;}
note: the user choses the a computer from a list and a software as will
for example the program will show the user 2 computers
0 for computer: apple, Model: mac mini, Speed: 2.8
1 for computer: sony, Model: vaio, Speed: 2.2
the user enters the index he wants then the program will show a list of software to add to the computer selected
the error I'm having is run time error Exception in thread "main" java.lang.NullPointerException and it points to these 2 lines
1.comp[Cch].setSoftware(software,Sch);
2. the method setSoftware
every thing is running correctly but this step above
Cch= the chosen computer index
Sch= the chosen Software index
why am i getting an error and how to fix it?
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