Java: Blank File on writing

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I am trying to write to a file in Java using the following function:

public void writeTextFile(String filename, double s){
  FileWriter output=null;
  try{
    output= new FileWriter(filename);
    BufferedWriter writer=new BufferedWriter(output);
    String ss = String.valueOf(s);
    writer.write(ss);
  } catch (Exception e) {
    throw new RuntimeException(e);
  } finally {
    if (output != null) {
      try {
        output.flush();
        output.close();
      } catch (IOException e) {

      }
    }
  }
}

I also tried using:

FileOutputStream out;
PrintStream prt;
try{
  out= new FileOutputStream("result");
  prt=new PrintStream(out);
  prt.println(value);
  prt.flush();
  prt.close();
}
catch(Exception e){
  System.out.println("File write error");}

But i end up with a blank output file with both the methods. Need help!!:(

This will work,

public void writeTextFile(String filename, double s){
 FileWriter output=null;
 try{
  output= new FileWriter(filename);
  BufferedWriter writer=new BufferedWriter(output);
  String ss = String.valueOf(s);
  writer.append(ss);
  writer.close();
} catch (Exception e) {
  throw new RuntimeException(e);
} finally {
  if (output != null) {
  try {
    output.flush();
    output.close();
  } catch (IOException e) {

  }
}
}
}

Create a new empty file in Java, A new empty file with the required abstract path name can be created using the method java.io.File.createNewFile(). This method requires no  How to write into a file ? This example shows how to write to a file using write method of BufferedWriter. The above code sample will produce the following result. File created successfully. The above code sample will produce the following result.

Hey its simple the error is that you aren't flushing the bufferedwriter please do that before you flush and close the stream.

add this to your first code

public static void writeTextFile(String filename, double s){
        FileWriter output=null;
        try{
            output= new FileWriter(filename);
            BufferedWriter writer=new BufferedWriter(output);
            String ss = String.valueOf(s);
            System.out.println("ss:"+ss);
            writer.write(ss);
            writer.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (output != null) {
                try {
                    output.flush();
                    output.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

How to Write a File Line by Line in Java?, This post summarizes the classes that can be used to write a file. 1. FileOutputStream public static void writeFile1() throws IOException { File fout. About File Handling in Java. One this page you can find a simple guide to reading and writing files in the Java programming language. The code examples here give you everything you need to read and write files right away, and if you're in a hurry, you can use them without needing to understanding in detail how they work. File handling in Java

try this

use this link : Tutorial on file writing

Code from the link :

public static void main(String[] args) {
        try {

            String content = "This is the content to write into file";

            File file = new File("/users/mkyong/filename.txt");

            // if file doesnt exists, then create it
            if (!file.exists()) {
                file.createNewFile();
            }

            FileWriter fw = new FileWriter(file.getAbsoluteFile());
            BufferedWriter bw = new BufferedWriter(fw);
            bw.write(content);
            bw.close();

            System.out.println("Done");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

Create new empty file using Java, Create new empty file using Java. By Yashwant Chavan, Views 58238, Last updated on 14-Nov-2016. In this tutorial you will learn how to create new empty file  Write File using Java 7 Path. Java 7 introduced Files utility class and we can write a file using it’s write function, internally it’s using OutputStream to write byte array into file. public static void usingPath() throws IOException { String fileContent = "Hello Learner !!

What if you try:

File file = new File("c:/newfile.txt");
    String content = "This is the text content";

    try (FileOutputStream fop = new FileOutputStream(file)) {

        // if file doesn't exists, then create it
        if (!file.exists()) {
            file.createNewFile();
        }

        // get the content in bytes
        byte[] contentInBytes = content.getBytes();

        fop.write(contentInBytes);
        fop.flush();
        fop.close();

        System.out.println("Done");

    } catch (IOException e) {
        e.printStackTrace();
    }

Based on this tutorial: http://www.mkyong.com/java/how-to-write-to-file-in-java-fileoutputstream-example/

Java, The many ways to write data to File using Java. We'll also take a look at locking the file while writing and discuss FileLock lock = null ;. try {. Finally, when writing to a file, you sometimes need to make extra sure that no one else is writing to that file at the same time. Basically – you need to be able to lock that file while writing. Let's make use of the FileChannel to try locking the file before writing to it:

You have to flush and close BufferedWriter not FileWriter.

Java Write to File - 4 Ways to Write File in Java, FileWriter: FileWriter is the simplest way to write a file in Java. os = null; try { os = new FileOutputStream(new File("/Users/pankaj/os.txt")); os.write(data. This page discusses the details of reading, writing, creating, and opening files. There are a wide array of file I/O methods to choose from. To help make sense of the API, the following diagram arranges the file I/O methods by complexity.

A Simple Example to Check if File is Empty in Java, One of the readers of my blog Javarevisited emailed me yesterday about how to check if a file is empty in Java and that's why I am writing this post to show that  a completely empty file; a file consisting of a single empty line; a file with a non-empty line, or multiple lines. You can probably do better by using Files.length() and / or reading just the first two bytes. However, the problems include: If you both test the file size AND read the first few bytes then you are making 2 syscalls.

How to write to File in Java using BufferedWriter, Java provides many convenient wrapper classes for reading and writing data into files e.g. you can use PrintWriter to write data line by line into the file. It's println()​  Notice I changed the forward slashes to double back slashes for paths in Windows File System. This will create an empty file on the given path. On Windows, both \\ and / are valid. The createNewFile() is by the way unnecessary when you write to it with FileOutputStream anyway.

Java - Create New File, false if the file already exists or the operation failed for some reason. Please note that this method will only create a file, but not write any content to it. FileWriter: FileWriter is the simplest way to write a file in Java. It provides overloaded write method to write int, byte array, and String to the File. You can also write part of the String or byte array using FileWriter. FileWriter writes directly into Files and should be used only when the number of writes is less.

Comments
  • it works fine... are you assigning 'value' ??
  • try adding writer.flush and writer.close in 1st code.
  • What is printed if you add System.out.println("value: '" + value + "'");?
  • @DarthCoder : value=esa.getRelatedness(args[0], args[1]);
  • Adding close() works. Flush before close is redundant.
  • There's nothing wrong with instantiating a FileWriter directly using the filename. Using File is not necessary.
  • you are correct , its another option not necessary ... Edited.
  • You don't need to call createNewFile(). Poor quality tutorial.
  • You don't need to call createNewFile(), or flush before closing. Poor quality tutorial.
  • @EJP no need to downvote, they're just patterns (it's not a poor qualit tutorial). Read here stackoverflow.com/questions/9620683/… and here stackoverflow.com/questions/9858495/using-flush-before-close
  • While this is correct, it's already been said (and accepted) by others. You should only answer if it adds something that someone else hasn't said.
  • And you don't have to flush, only close.