Java Programming Tutorial - 80 - Writing to Files Video Lecture - Java

what is going on guys it is Bucky and
welcome to your 80th Java tutorial in
this story I'm going to teach you guys
how to add data to your files so in the
last story we pretty much learn how to
create an empty file not that useful so
let's go ahead and put something in it
in this tutorial and hold on one second
I got to itching right here I felt good
I got it all right so let's go ahead and
import a couple things we need to import
Java dot IO and let's go ahead and
import everything from there and as you
can see I made a separate class outside
my main class and I just named it create
file because that's where we're going to
be doing creating files that's why I
named did that so next let's go ahead
and put Java dot Lang we need some crap
from in there and lastly let's go ahead
and import Java dot util I'm not exactly
sure what we're going to be building in
this tutorial but this should cover
everything so without further ado let me
think what do I want to do first well
the first thing we need to do is do a
private formatter variable and I'm going
to name on X as usual and what this is
going to do is hold a formatter object
and let's go ahead and make a method to
pretty much create and open a file so
let's go ahead and put public void and
we'll just name it Open File you name it
whatever you want
it's a doesn't like any parameters
because they're just going to open a
file now in this method what we want to
do we got to have our try and catch
block like always so let's go ahead and
try and set X equal to new for Matt's or
object in go ahead and write a file name
um make sure you write one that you
don't already have a file or else you're
going to overwrite it so I don't have a
file called like Chinese text you
probably don't either so you can use
that so go ahead and try and set this
file equal to X if you can't let's just
go ahead and catch an exception
catch exception II and this pretty much
means if you get an error what do you
want to do
let's do system.out.print line just put
you have an air air no error there we go
alright so now when we ever recall this
method open file it's pretty much just
going to set X equal to this file it's
pretty much just going to give us a file
so we can use so now we have a file that
we can use so what we want to do to that
well we want to add a record to it so
let's go ahead and put public void add
records and let's go ahead and this is
going to take any parameters either and
adding records is the easiest thing in
the world all you need to do is put the
file you want to add to which is X
because remember we set equal to Chinese
dot txt and what you do is the method is
format and this pretty much is like
printf for files and now again how
familiar is this the format and the
arguments so for the format let's let's
insert three strings the first one say
we're making like a user account the
first one will be the ID number so we'll
put like 20 it's my favorite number and
the second one will be my first name
which is Bucky and the third piece of
data will be Roberts which is my last
name so I looks good right there so now
what this is going to do is insert three
elements in the same line it's going to
say 20 Bucky Roberts it's going to
insert that in our file whenever we call
this method add records and the last
thing that we want to do is write a
method to close the file so go ahead and
write public void close file or name it
whatever you want but that's pretty easy
to remember and why do we need to put oh
I would show you guys what the thing is
X close and closes built-in methods
that's why we can use this and that's
why we need to include all these so we
can use this close method but now let me
tell you guys why we need to close this
file it's pretty much like a
housekeeping thing whenever we exit our
program windows usually and I say
usually closes our file from writing so
nothing else can write in it but
sometimes remember every operating
system is different sometimes depending
on your program it can leave the file
open it can lead to some errors so you
always want to close your files it's
good programming you always want to do
it I mean you can probably get away with
not doing it but if you ever get job as
a Java programmer there are going to be
pio to you if you forget to close your
files it's probably going to cause some
errors later down the road so we're
pretty much recap talking about
something different now we're pretty
much got three methods in here we need
to open the file we need to add some
records into it and then we need to
close the file because we're done with
it we don't want anyone else messing
with it so go ahead and in your main or
whatever your main method is just go
ahead and well we don't need to include
anything but what we do need is to
create an object and I named my class
create file so create firearms can name
it like G or something new
great file doesn't take any parameters
we didn't make a constructor and
remember we have three methods you go
open file right there
G would rename it add records right
there and so now we open the file we
added the records and now what we need
to do is close that file because we're
done with it and now once you go ahead
and run this program
nothing happens but what it did is
created a file on our computer so if we
highlight source are actually Bucky and
put file refresh it's pretty much going
to refresh our computer so now you see
we get this Chinese text file that we
just created and the cool thing about
eclipse is is actually a text editor as
well so double click this file and I'll
show you what's in your file and that is
20 Bucky
Roberts this one is just the line number
don't mind that that eyes is actually in
the file so in this text file we have 20
Bucky Roberts
so now let's recap one last time what we
did in create file that Java is pretty
much the meat of our program we created
a method to create a file and that was
open file right here and we needed a
try-catch because of Java and we said
all right we're going to look for
Chinese text that file we want to write
on if we don't have it already then
create a new one so we can write in it
and that's what X new formatter does so
now we have a Chinese text file so we
can write text in it so what do we want
to write in it well we just wanted to
add a record we gave myself like an ID
number
Bucky Roberts and if we had to make like
a system of like I had to make like a
library for school or they have like
credit card numbers or anything where
you need a ID number you'd add a record
after record after record and you called
this method a bunch of times and I just
moved that and then that's how you get
like a database on your computer and
then after that you just close your file
so you can't mess with that anymore and
that's pretty much it so uh thank you
guys for watching I hope you learned a
little something and hopefully I got
this so you guys can see it but oh well
I'm done with Orion noise so anyways
thank you guys as it just said don't
forget to check out my giveaways and
don't forget to subscribe so I'll see
you next time