How to save file using JFileChooser?

I have a method in my application called "Save as" which Saves the image of my application on computer my into a file. I used the JFileChooser to let the users choose their desired location开发者_JS百科 for saving the file. The problem is unless user explicitly types in the file format, it saves the file with no extension. How can I have formats like jpg, png in the File Type drop down menu.

and, how can i get extension from the File Type drop menu for saving my image file.

 ImageIO.write(image,extension,file);

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Finally, I solved my own problem:

JFileChooser fc = new JFileChooser("C:/");
fc.addChoosableFileFilter(new JPGSaveFilter());
fc.addChoosableFileFilter(new JPEGSaveFilter());
fc.addChoosableFileFilter(new PNGSaveFilter());
fc.addChoosableFileFilter(new GIFSaveFilter());
fc.addChoosableFileFilter(new BMPSaveFilter());
fc.addChoosableFileFilter(new WBMPSaveFilter()); 

int retrieval = fc.showSaveDialog(null);

if (retrieval == JFileChooser.APPROVE_OPTION) {
  String ext = "";

  String extension = fc.getFileFilter().getDescription();

  if (extension.equals("*.jpg,*.JPG")) {
    ext = ".jpg";
  } else if (extension.equals("*.png,*.PNG")) {
    ext = ".png";
  } else if (extension.equals("*.gif,*.GIF")) {
    ext = ".gif";
  } else if (extension.equals("*.wbmp,*.WBMP")) {
    ext = ".wbmp";
  } else if (extension.equals("*.jpeg,*.JPEG")) {
    ext = ".jpeg";
  } else if (extension.equals("*.bmp,*.BMP")) {
    ext = ".bmp";
  }
}

Example Filter:

package example

import java.io.File;
import javax.swing.filechooser.FileFilter;

class JPGSaveFilter extends FileFilter {
  @Override
  public boolean accept(File f) {
    if (f.isDirectory()) {
      return false;
    }

    String s = f.getName().toLowerCase();

    return s.endsWith(".jpg");
  }

  @Override
  public String getDescription() {
    return "*.jpg,*.JPG";
  }
}

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Prepare the file chooser filters:

    jFileChooser.addChoosableFileFilter(new FileNameExtensionFilter("File X (.xxx)", "xxx"));
    jFileChooser.addChoosableFileFilter(new FileNameExtensionFilter("File Y (.yyy)", "yyy"));
    jFileChooser.addChoosableFileFilter(new FileNameExtensionFilter("File Z (.zzz)", "zzz"));

    // set default type
    jFileChooser.setFileFilter(jFileChooser.getChoosableFileFilters()[0]);

    // set default file
    jFileChooser().setSelectedFile(defaultFile);

After approve validation

//Add extension to Selected file 
File file = new File(jFileChooser().getSelectedFile().getCanonicalPath() + "." + ((FileNameExtensionFilter) jFileChooser().getFileFilter()).getExtensions()[0]);

Could be a good idea validate if the selected file come with extension.

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Use JFileChoose.SetFileFilter example: http://www.java2s.com/Code/JavaAPI/javax.swing/JFileChoosersetFileFilterFileFilterfilter.htm

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I think I got better solution. Will explain it with sample code fragments.

This is how I set file filter:
jFileChooser.setFileFilter(new FileNameExtensionFilter(".txt", "txt"));.

After this the main saving line:
textArea1.write(new BufferedWriter(new FileWriter(jFileChooser.getSelectedFile().getAbsolutePath() + jFileChooser.getFileFilter().getDescription().replace("All Files", ""))));.

Of course the most important is this fragment: jFileChooser.getSelectedFile().getAbsolutePath() + jFileChooser.getFileFilter().getDescription().replace("All Files", "").

The only thing I don't like is, that I could not find any method like 'getExtension' which means that You cannot have any nice description without unnecessary troubles with strings.

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Ok, got it. You can do something like that: jFileChooser.getFileFilter().toString().replaceFirst(".*extensions=\\[(.*)]]", ".$1").replaceFirst(".*AcceptAllFileFilter.*", "").

Unfortunately it's not so beautiful, but seems to work like a charm.