I have this program.exe which, after being called from a command line environment, e.g.: C:\> program.exe input.inp automatically writes a file (with a generic name), e.g. "output.out", in the directory I am working in. However, when I try to call this program.exe from my java code, it does not write the output.out file as it does when using the command line. ... |
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static void Reordering_solution(FileWriter writer_rordering_out,File reordering){ try { /////////////////////////////////////////////////////////////////////// // some commands/////////////////////////////////////////////// // writing into file////////////////////////////////////////////// for (int g = 0; g < test_after_filling_ordering.size(); g++) { writer_rordering_out.write(test_after_filling_ordering.get(g).toString()); writer_rordering_out.write("\r\n");} writer_rordering_out.write("Empty"); writer_rordering_out.write("\r\n"); ///////////////////////////////////////////////////////// // close writing ///////////////////////////////////// writer_rordering_out.close(); ////////////////////////////////////////////// reading data written/////////////////////// ////////////////////////////////////////////// Scanner inFile_77= new Scanner(new FileInputStream(reordering)); BufferedReader reader_reordering_sub = new BufferedReader(new FileReader(reordering)); line_reodering = null; line_reodering = reader_reordering_sub.readLine(); line_reodering=inFile_77.nextLine(); /////////////////////////////////////////////// //some command ... |
hello I have problem with reading and writing the files I need to do calculation to obtain data and then writing this data into file, the data is large. the data is saved in vector so I need to write each element of vector in line in the file. the each elemtn of vector contains 97 numbers. my problem is that ... |
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I am facing problem to write in file.. At first i read from file successfully.Now I want to write them on another file..It is working,,But not approprietly... It is working only for 1st line.Not others... I think problem is here.. ((strLine=br.readLine())!=null) input file:: UJJAL DHAR TAKI BUT OUTPUT FILE: UJJAL DHAR At first line there is null..what should i do for ... |
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here is my code: import java.util.*; import java.io.*; public class ReadFile { public static void manin(String[] args) throws FileNotFoundException { Scanner inFile = new Scanner(new FileReader("C:\\Users\\Usman\\Desktop\\employeeDat a.txt")); PrintWriter outFile = new PrintWriter("C:\\Users\\Usman\\Desktop\\wages.txt" ); String Firstname, Lastname; double hours,payrate,wages; Firstname = inFile.next(); Lastname = inFile.next(); hours = inFile.nextDouble(); payrate = inFile.nextDouble(); wages = hours*payrate; outFile.println("$"+wages); inFile.close(); outFile.close(); } } Plz tell me ... |
I've been able to write a program to read and write files, however, I've been unable to edit already written files. I've been writing files using the Formatter class, but this creates an entirely new file and so I haven't been able to use this to edit a file rather than rewriting it completely -- is it even possible to do ... |
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I'm trying to create a save game system for a program I'm making. I'm trying to do this by having the player save their progress to a file with the extension .ksm by writing the player's current data of the currently active "Mission" object (containing everything needed to continue the game from where it was left off) to said file using ... |
so basically what i want to do is add data(variables namn, efternamn and personnumer, which means name, lastname and social security number) to a file.. i managed to update a file but i just want to add a a person to this file, and nothing else... heres what i got so far: Java Code: import java.io.*; import javax.swing.*; public class Kund ... |
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import java.util.Scanner; import java.io.*; public class Scann { public static void main(String [] args) throws Exception { System.out.println("Enter 0 to exit:"); System.out.println("Enter your name:"); Scanner sc = null; while(true) { File objFile = new File("Hello.txt"); FileWriter objWrite = new FileWriter(objFile); //Writer objWriter = new BufferedWriter(new FileWriter (objFile)); //FileOutputStream os = new FileOutputStream(objFile); sc = new Scanner(System.in); String name = sc.nextLine(); if(!name.equals("0")) ... |
I am having a problem with one part of my program i have to "have a method named "public void generateEmployees(int howmany)". In this method, based # on the value of the input parameter "howmany", you create "howmany" employees and store them in # the variable "allE" and have a method named "public void storeInfo(String filename)" in which you write out ... |
import java.io.*; import java.util.*; public class StudentsRecords { public static void main(String[] args){ Scanner scan = new Scanner(System.in); try{ FileWriter fstream = new FileWriter("C://Users//dell//Desktop//G E N E R A L//J A V A//Records.txt"); BufferedWriter out = new BufferedWriter(fstream); int size=0; System.out.print("Enter number of students: "); size = scan.nextInt(); String name=""; int mark=0; for(int i=0; i |
So the problem is, that, i am reading from a file and am placing it into arrays. How am i suppose to edit the file using a gui that i will be creating? For example: There is this cd file that i am reading from, and have placed the title, singer, price, discount and all on the array and this details ... |
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I need to use an interface to write to a file 5 times. My interface includes a book title, author ,and availability. I am to save all of this to a file 5 times where I will then create another program to read this file and perform a search. My question is: when I write to the file, it keeps replacing ... |
public class MyFrame extends JFrame{ //class ... public MyFrame(){ //constructor listenToWindow(); //call method ... public void listenToWindow(){ //method addWindowListener //execute my window listener (new WindowAdapter(){ //used WindowAdapter public void windowClosing(WindowEvent e){ //an inherited method from class WindowListener setTitle("Closing window..."); //change current title to identify that it is closing try{ Thread.sleep(SLEEP); }catch (InterruptedException error){ System.out.println(error.getMessage()); } for (int i=0; i |
import java.util.Scanner; import java.io.*; public class StringVariables { public static void main(String[] args) { try{ // Create file FileWriter fstream = new FileWriter("out.txt"); BufferedWriter out = new BufferedWriter(fstream); Scanner user_input = new Scanner (System.in); String userId; System.out.print("Enter Product ID: "); userId = user_input.next(); String productName; System.out.print("Enter product name: "); productName = user_input.next(); String productPrice; System.out.print("Enter product price: "); productPrice = user_input.next(); ... |
Hi, I am trying to write to a text file in java but whenever I input data it gets deleted. The code I am going to post is a very small sample (just the IO component) but basically the purpose of the IO is whenever someone types something on the cell of my Calendar JTable it saves there and the entry ... |
import java.io.*; class FileRead { public static void main (String args[]) { try { // Open the file that is the first // command line parameter FileInputStream fstream = new FileInputStream ("test.txt"); // Get the object of DataInputStream DataInputStream in = new DataInputStream (fstream); BufferedReader br = new BufferedReader (new InputStreamReader (in)); String strLine; //Read File Line By Line while ((strLine ... |
long prevLength = 0; Thread.sleep(300); long newlength = file.length(); System.out.println("Previous size: " + prevLength); // print out the size for testing System.out.println("New size: " + newlength);// print out the size for testing while(prevLength < newlength){ prevLength = newlength; Thread.sleep(250); newlength = file.length(); System.out.println("Previous size: " + prevLength);// print out the size for testing System.out.println("New size: " + newlength);// print out the ... |
Hello JF residents, I have a new problem, still going through the Java tutorial over at the Oracle site. I am excited because I went through the generic tutorial and while I get it conceptually, I am not yet comfortable using it. Same can be said of the Exceptions tutorial. Asides from throws IOException which I mostly use because I saw ... |
Hello: I'm trying to create a file that writes to a file the scores of 2 players in a game. In my text, there are many example of writing to a file, however, none of them show how to retrieve/accept a variable (in this case, the score) from another file to use in writing to a new file. Here is my ... |
Instructions: 1. Program will ask the user for a number input (integer). 2. Program will then produce the stars ("*") as a square. However while it is printing a line of stars("*"), it will also write each set (line) of stars on a text file vice displaying on screen. 3. The program will then open the same text file for reading, ... |
import java.io.*; class PrintStreamDemo { public static void main(String args[]){ FileOutputStream out; PrintStream ps; // declare a print stream object try { // Create a new file output stream out = new FileOutputStream("myfile.txt"); // Connect print stream to the output stream ps = new PrintStream(out); ps.println ("This data is written to a file:"); System.err.println ("Write successfully"); ps.close(); } catch (Exception e){ ... |
class DataBase { private BufferedWriter fileStream; // private Formatter x; public void openFile() { try { fileStream = new BufferedWriter( new FileWriter("Users.txt")); } catch (IOException e) { e.printStackTrace(); } // x = new Formatter("users.txt"); } public void addUser(String firstName,String lastName) { // x.format("%s\t%s\n",firstName,lastName ); try { fileStream.write(String.format("%s\t%s\n", firstName,lastName)); } catch (IOException e) { e.printStackTrace(); } } public void closeFile() { // ... |
Hi experts, I need to know how to write data to a file without deleting the existing data in it. Is there any simple way(im extremely new to Java). I just wrote coding to write to the file. And also I need to know about creating and maintaining a Database in Java. Please recommend some appropriate books for me to begin. ... |
you have a text file with averaes for students with student number, class name and class average. you need to class name and class average of all entries and then splitt them into two text files as outputs depending on whether the average is 50 or more. So my question is, how do i only target the class name and average ... |
Now I want to increment the number and write it on to the same file..... But the problem is what class(like FileOutputStream ) I should use so that I need not include the full path as "src/com/sequence/Sequence.txt"......... I need to give only the path "com/sequence/Sequence.txt"... In other words ... is threre any method which takes this relative path and returns OutputStream..... ... |
Hello, i have to write HTML files from a java application. I am asking if anybody can give me a hint about a good simple solution (library) which can do some of the job for me. i know FOP for example is good to create pdf or html from xml, but i dont want to go via xml. the sites i ... |
I'm not sure I understand, or maybe I didn't explain very well. I am putting the original and reverse in separate array elements like array[0] = original and array[1] = reverse. What I can't figure out is how to specify how many elements I need for the array[] to be to hold all of the text (originals and reverses). If I ... |
while ((line = in.readLine()) != null) { String cleanline = stripNonValidXMLCharacters(line); //our own method to do something handle(cleanline); //count each line count++; } in.close(); //show total at the end of file log("Lines read: " + count); } catch (IOException e) { log(e.getMessage()); } dlxmlwriter(); //final write for process xmlwriter(""); //write base element end tag } // does the work on every ... |
What I understood is that there is a file residing at web.telecom.cz and its name is xanado.txt. I am assuming that you are able to see this file by typing the URL - http://web.telecom.cz/xanado.txt write to this file. To read this file through a Java program, use the HttpURLConnection to read this file. However to write a file, you have to ... |
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It's good practice to close any InputStream or OutputStream as soon as you're finished with it. After you've read the ArrayList from the file, there's no additional use for the ObjectInputStream. One thing I was not clear about--when you call (ArrayList)objectIn.readObject(), the ArrayLIst it returns will already contain your Book objects. Try adding a print statement inside the for loop. If ... |
+ try{+ + data = inputMethod();+ + fileName = inputMethod();+ + FileWriter writer = new FileWriter(fileName);+ + writer.write(data);+ + writer.close();+ + }+ + catch(IOException e) {+ + System.out.println("Unable to Open/create File!");+ + }+ + }+ My problem is this: when I need to add more data to the same file, how shall I do it? As I closed the file I ... |
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Hi, I'm trying to make an application that is sorta like a database (although maybe not as complicated!). It's just a program that contains a list of cars and a few other details (like year, make, color and a few others). There are 2 buttons: New and Edit. When they press the new button, a menu pops up with blank fields ... |
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Hi everyone, I'm writing a simple game (pong) that I want to track high scores for. I currently have HighScores.txt in the classes folder to track these scores. I'm using the Scanner to read the scores in, and it reads fine, but when i try to overwrite a score, a AccessControlException is thrown. the message is : Exception in thread "AWT-EventQueue-1" ... |
Currently I've added my write method to the bottom of one of my classes, but every time I invoke the write method it creates file.txt with the desired output saved into it, but when I invoke the method again it just writes over it. Does this mean I need to create a separate class for reading and writing? |
Yes, I know that... I was thinking from the standpoint that Strings, unlike most objects, are extremely easy to convert into a primitive object (an array of chars). My question was more-so directed about the fact that, when being written/read, a String's "unknown length" would have to be taken into account - thus I asked if it was treated like an ... |
it isnt working because when i compile and run it the updated file isnt getting written with what i want .. it seems to be stuck in an infinite loop .. any suggestions or alternatives to solve the problem are also welcome to test it i even added a system.out.print(tempc) to check if besides the writing to file the long value ... |
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Writing a large scale application that involves several threads that read different parts of a file, correct their respective part, and recreate the file. Is it possible for each of the threads to write to different parts of the same file simultaneously? Speed is an issue here so any tips would be helpful thanks. |
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Hi , I am reading a MSAccess file (mdb) from one location to another location .but the source file is an online database which will chage regularly .so while reading that file i am getting error like FileNotFoundException. java.io.FileNotFoundException: c:\Msaccess\db2.mdb (The process cannot access the file because it is being used by another s) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:106) at read.main(read.java:16) ... |
I would also like to know how to write a PNG, GIF, BMP, JPEG, or TIFF file from my current black and white BufferedImage. Also, I see on the forum some talk about a Scalable Vector Graphics API but I don?t see SVG anywhere in the alphabetical class list in the java documentation. |
*/ import java.io.*; class ReadWrite1 { public static void main(String s[]) { File in=new File("in2.txt"); File out=new File("out2.txt"); FileReader ins=null; FileWriter outs = null; try { ins=new FileReader(in); outs=new FileWriter(out); int ch; while((ch=ins.read())!=-1) ( outs.write(ch); } } catch(IOException e) { System.out.println(" "); } finally { try { ins.close(); outs.close(); } catch(IOException e) { } } } } |
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Hi, i have encountered a problem reading the names of files with chinese characters. everything comes out as ?????.txt. the same goes when i write these file names to a txt file. can you advice me on how do i detect chinese in strings and how do i write them as chinese characters into a file? all help appreciated. regards shaun ... |
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K so I have a String file which is the path to a file on the computer, its already been checked and everything and it exists, and exceptions are handled and all that junk all I want to do is read one line at a time from that file, change it, then put it back in at the same spot. how ... |
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I have used the code shown above to get the details of the course from the user and write it to the file. However, In my assignment there is a part where "I'm supposed to read from the same file(course), change one of the names of the student and write it back again to the same file". So to solve this, ... |
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My dilemma is i am wanting to write an arraylist to a specific folder within the package mounted in Netbeans. My only problem is I am running on a mac and cannot get to write to correct place. I have tried to use /.../file name etc. It works if i explicitly give the whole path but i do not want to ... |
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How can I write to a file without deleting all the information stored in the file. Everything I have tried so far will delete all the contents before writing to the file. The only way I have been able to get around this is to read the file, store it in the memory, then write it back to the file before ... |
Can someone show me how to write a simple program that I can run on the command line that will write the following information to a file? long heapSize = Runtime.getRuntime().totalMemory(); long heapMaxSize = Runtime.getRuntime().maxMemory(); long heapFreeSize = Runtime.getRuntime().freeMemory(); The executable command line file will be named get_heap_size. It will write a file named java_heap_size that contains: Heap Size = Max ... |
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Hi, I want to write a program which has a log file to record every action. I do have the data written to the target file. But every time I run it again the previous log is overwritten! I tried methods of print, write in classes such as FIleOutputStream, BufferedWriter, PrintStream. And in the sun document I didn't find information about ... |
txt1 is used in startreading() when it has not been created in setup(). You should create a TextField and assign it to txt1 there. Otherwise it's still null. Also, you'll see that only the last character of your file is displayed. You'll have to append the characters until end-of-file using something like a StringBuffer. |
In the case of an application I wrote, I created an ImageIcon object. Now I want to create an Icon file out of the object so that the user has an actual icon on their machine. You can of course write any data to a file, but that won't make the file valid for the format. I can write a jpg ... |
sorry I should really look at my code more closely before posting on the forums (or at least drink more coffee before sitting at my desk). The file name README_InputFile.out should have been README_InputFile.txt. It works perfectly fine. The problem has now been resolved. Thank you for your help and patience. Message was edited by: Jazman |
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well basically what I was trying to accomplish was something like this. It lists the order of the numbers then displays the numbers next to it. Something like: 1 343 2 667 3 778 4 888 5 991 then i was trying to send any odd number in the original file to a file called odd.out. so if i were using ... |
i am facing some problem reading a line and writing into a file can any one hel pme... 1. i have this line in program MRO_INTERNAL_OUT_CLA_CreateOrder_RESPONSE i need to get out put as MRO_INTERNAL_OUT_CLA_CreateOrder_RESPONSE and 268520629#268771030 but i got output only 268520629#26877103 268520629#268771030 help me with code.......i am using buffered reader and writer..please explain with code Message was edited by: ... |
iam reading a file and writing some contents to a file....It working properly i get output on a file as success iwant to get output in following format.... ticket no status ______________________----------------- success Note that i only extract some contents from a fileand write to another file.Can anyone help me |
What's the point of creating the input file if it isn't there? So you can read from an empty file? If the file isn't there, new FileInputStream() will throw a FileNotFoundException. That's all you need. And testing for the file's existence after you call new FileInputStream() is therefore completely meaningless. If the file isn't there you won't get to execute the ... |
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I want to keep what's in the file right now exactly the same, but add more stuff at the end. So yeah i want to write from the end fo the file, meaning that i want to add a new line of text to the file i already have. Edited by: deathcholo on Jul 10, 2010 4:31 PM |
It says "File doesn't exist!!" because you've put wrote a line of code in your program to do that. I'm not sure what you mean by "the output box", since there's nothing in your code to do that either. Presumably you mean your IDE. A File object doesn't cause anything to come into existence. It's really just a reference to a ... |
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I think I'm getting myself confused. My thought process before was this: I need to read in data from a file and put it into a table (DefaultTabelModel won't allow strings, no?). I then need to add data to the file and the table. I was planning to do this by writing to the file and then updating the table from ... |
Umm... I'm pretty sure this doesn't even compile... You are declaring the variable lineContents inside the while loop but reading its value outside. Aside from that you never close any of the streams, you mixed up the file names for bgp and bgldata. Also you are missing an else after your if statement. All in all you should: a) provide a ... |
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Packages are great for Java classes but I don't really think the intent is to store every file you create at runtime in them. I mean what if your program runs from a JAR? Creating new files in the working directory at runtime is okay. From a best practices perspective you could do any of the following depending on your specific ... |
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Hi all, I have to write a file in a java program. I am using DataOutputStream() method for that. Its all fine. I need to know how could I add a carriage return in my file. like say I need to write... Hello Java World I hope same solution will work for tabulator too..... |
Why the multiple arrays? I'd just read it into List... an extensible collection of "the fields on each line"... then you just write them out as required. second-field + comma + first-field. I suggest your next move should be to take a backup copy of your current class then rip-all that commented-out code out of it, and ... |
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Example: strOutput = strPolicyNumber.PadRight(15) & _ intNameCounter.ToString("00") & _ "110" & _ "00001" & _ "0" & _ Space(5) & _ strLastName.PadRight(25) & _ |
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TRANSLATE: Hola, Creo que no se puede aadir al principio de un archivo directamente con una funcion de la API de JAVA. Para hacer eso lo que tienes que hacer es leer linea por linea y pasarlas a un nuevo fichero en orden inverso. Si, por otro lado, lo que quieres es aadir al final tal vez puedas usar la funcion ... |