How to check if a file exists in java

Question

Im having a problem in checking if a file exists in Java. However the IF block seems to work , but the ELSE seems dont. see, when a file exist, it will prompt a box that says, 'File found.' which happens in my program whenever a file do exist, the problem is errors flood in my console when a file dont exist. Can somebody tell me what's the easier and shorter way of coding my problem? thanks ! here's my code

        public void actionPerformed(ActionEvent e) {
             BufferedReader br = null;
             File f = new File(textField.getText());
             String path =  new String("C:\\Users\\theBeard\\workspace\\LeapYear\\");
            try {

                String sCurrentLine;

                br = new BufferedReader(new FileReader(path+f));
                if (f.exists())
                {
                    JOptionPane.showMessageDialog(null, textField.getText()+" found" );
                    while ((sCurrentLine = br.readLine()) != null) {

                         textArea.append(sCurrentLine);
                         textArea.append(System.lineSeparator());
                    }
                }
                else
                {
                    JOptionPane.showMessageDialog(null, textField.getText()+" not found" );
                }


            } catch (IOException ex) {
                ex.printStackTrace();
            } finally {
                try {
                    if (br != null)
                    {

                        br.close();
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }

    }


    });

http://stackoverflow.com/questions/1816673/how-do-i-check-if-a-file-exists-in-java — Swapnil, Aug 21 '15 at 15:30
This is 2015; don't use File anymore. Use JSR 203, and in this case, `Files.exists()`. — fge, Aug 21 '15 at 15:31

M A · Answer 1 · 2015-08-21T15:51:13.827

The problem is with this line:

br = new BufferedReader(new FileReader(path+f));

You're appending a File to a String, which doesn't make sense. You should append a String to a String, in this case textField.getText()) appended to path.
This line will throw an exception if the file doesn't exist as per the documentation of FileReader:

Throws: FileNotFoundException - if the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.

This causes your program to reach the catch clause and print an exception stack trace. You should only call this line when f.exists() returns true:

if (f.exists())
{
    br = new BufferedReader(new FileReader(path + textField.getText()));
    ...
}

score 1 · Answer 2 · answered Aug 21 '15 at 15:32

Look at these lines of your code:

br = new BufferedReader(new FileReader(path+f));
if (f.exists())

You are trying to open the file before checking whether it exists. So if the attempt to open it fails with a FileNotFoundException, the test is never reached.

Xirema · Answer 3 · 2015-08-21T15:36:46.697

0

String path = "C:\\Path\\To\File\\Directory\\";
String fileName = "NameOfFile.ext";
File f = new File(path, fileName);
if(f.exists()) {
    //<code for file existing>
} else {
    //<code for file not existing>
}

edited Aug 21 '15 at 15:36

answered Aug 21 '15 at 15:31

Xirema

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Please explain your answer, just posting code does not constitute a full answer – Glenn Teitelbaum Aug 21 '15 at 16:35

score 0 · Answer 4 · answered Aug 21 '15 at 15:47

You have to instantiate the BufferedReader after checking the existence of the file.

String path =  new String("C:\\Users\\theBeard\\workspace\\LeapYear\\");
File f = new File(path + textField.getText());
...
if (f.exists())
{
    br = new BufferedReader(new FileReader(f.getAbsolutePath()));  // or br = new BufferedReader(f);
    ...

How to check if a file exists in java

4 Answers4