Re: How to convert one text file into one large String?

From:

Eric Sosman <esosman@ieee-dot-org.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 05 Mar 2010 16:32:13 -0500

Message-ID:

<hmrt8u$lva$2@news.eternal-september.org>

On 3/5/2010 1:31 PM, Tom Anderson wrote:

On Fri, 5 Mar 2010, Tom Anderson wrote:

On Thu, 4 Mar 2010, Arne Vajh?j wrote:

On 04-03-2010 21:03, Roedy Green wrote:

On Thu, 04 Mar 2010 16:54:59 -0500, www<www@nospam.com> wrote, quoted
or indirectly quoted someone who said :

I searched all the methods in File.java(from Sun) and
FileUtils.java(from Apache) and could not find it.

see http://mindprod.com/products1.html#HUNKIO
for the source code

Given that a one liner using only standard Java API has been posted,
then there are no need.

Just for fun, here's a two-liner, where f is a File:

byte[] buf = new byte[(int)f.length()];
new DataInputStream(new FileInputStream(f)).readFully(buf);

Although of course that gets you a byte array, not a String. My bad. The
full answer is a three-liner:

String s = new String(buf, "UTF-8"); // or whatever charset you like

Although this involves using N bytes of memory for the buffer and up to
2N bytes for the string at the same time, if only briefly. There should
be a way to do it that just involves storing 2N bytes, and perhaps
Scanner does this.

It also assumes that f.length() returns the file's length.
It will do so if it can, but it may not be possible: Suppose
the "file" is a keyboard, or a pipe, or a socket, or something
else whose length won't be known until after all the data has
been read. In such cases, f.length() will return 0L ...

--
Eric Sosman
esosman@ieee-dot-org.invalid