Scan multiple file headers

I have a java program in a certain directory. I would like to make it find a list of all files that end with .dat or .DAT in the same directory as the program. Then I need to look at the first couple of lines of each file and parse a title string. The program should return an array of the file names, and an array of the first three lines of each file. I am pretty new to IO stuff, can anyone help?

Example: C:/my_directory/
Files: Program.class,
       FOO.DAT (starts with "Lorem\nipsem\n$$0")开发者_运维技巧,
       bar.dat (starts with "ipsem\nLorem\n$$0")

Return: ["FOO.DAT","bar.dat"] and ["Lorem\nipsem\n","ipsem\nLorem\n"]

Thanks in advanced!

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The following code snippet prints out all the files that have .dat or .DAT file extensions in a given directory. Try to figure out how you can read first three lines from a file. That must be fairly straightforward

        File tmp = new File( "/tmp");
        List<String> fileList = new ArrayList<String>();
        if( tmp.isDirectory())
        {
            for( File f : tmp.listFiles())
            {
                if( f.isFile() )
                {
                    if((f.getName().endsWith( ".dat") || f.getName().endsWith(".DAT")))
                    {
                        fileList.add( f.getName() );
                    }
                }
            }

            for( String fileName : fileList)
            {
                System.out.println( fileName);
            }
        }