Lambdas, New IO, and parsing textfiles in a hurry.

Okay, so I needed to do some parsing of a file containing URLs (which I "wget"-ted) and moving the retrieved files to proper locations.

I decided to write a quick Java program to do this instead of messing around with scripting languages or a Linux bash shell.

It worked very well, and I am rather pleased with the result and Java 8.

It contains the following "new/newer/not-very-old" stuff:

• a lambda
• a stream (of Strings)
• a method reference (used as a lambda)
• the java.nio.file package (New IO)

One small note: lambdas implement an interface. In this case the forEach requires a lambda that implements the Consumer interface. The Consumer interface does not specify an IOException. Therefore, I am required to catch it here and rethrow it unchecked.

	import java.nio.file.FileSystems;
	import java.nio.file.Files;
	import java.io.IOException;
	import java.nio.file.Path;
	import java.nio.file.Paths;
	public class ParseTextFile
	{
	public static void process(String url) {
	try
	{
	String filename = url.replace("http://","").replace("https://","");
	int index = filename.indexOf("/");
	filename = filename.substring(index+1);
	Path path = Paths.get(filename);
	Files.createDirectories(path.getParent());
	Files.move(path.getFileName(), path);
	System.out.println(filename);
	}
	catch (IOException e)
	{
	// e.printStackTrace();
	throw new RuntimeException(e);
	}
	}
	public static void main(String[] args) throws IOException {
	Files.lines(FileSystems.getDefault().getPath("list.txt")).forEach(ParseTextFile::process);
	}
	}

view raw ParseTextFile.java hosted with ❤ by GitHub

References

[1] Java SE 8 - Official Javadoc

https://docs.oracle.com/javase/8/docs/api/