Start learning with our library of video tutorials taught by experts. Get started

Java Essential Training

Managing files with Apache Commons FileUtils


From:

Java Essential Training

with David Gassner

Video: Managing files with Apache Commons FileUtils

In our previous video, I described how to copy the contents of the text file to a new text file, using tools that are available from the Java class library. I'm working in a copy of that project now called ApacheFileUtils that's a part of the exercise files for this course. In this application, I had to create a whole bunch of different objects two file object representing the existing file and the target file, an input stream and an output stream, a byte array, an integer, and then I had to loop through and read the file one set of bytes at a time and write out the new file.
Expand all | Collapse all
  1. 10m 8s
    1. Welcome
      1m 3s
    2. Is this course for you?
      5m 35s
    3. Using the exercise files
      3m 30s
  2. 31m 24s
    1. The history of Java
      5m 19s
    2. Java compilation and syntax
      8m 54s
    3. Understanding the principles of Java
      8m 28s
    4. Choosing a development environment
      8m 43s
  3. 19m 5s
    1. Installing Java on Windows
      6m 42s
    2. Installing Eclipse on Windows
      3m 19s
    3. Exploring Java on Mac OS X Leopard and Snow Leopard
      2m 27s
    4. Installing Java on Mac OS X Lion
      3m 27s
    5. Installing Eclipse on Mac OS X
      3m 10s
  4. 46m 10s
    1. Creating a Hello World application
      11m 7s
    2. Exploring the Eclipse IDE
      8m 55s
    3. Compiling and running from the command line
      8m 2s
    4. Passing arguments to the application
      8m 17s
    5. Using the Java API documentation
      4m 5s
    6. Memory management and garbage collection
      5m 44s
  5. 58m 57s
    1. Everything is an object
      5m 59s
    2. Declaring and initializing variables
      9m 15s
    3. Working with numbers
      8m 32s
    4. Converting numeric values
      6m 40s
    5. Understanding operators
      7m 58s
    6. Working with character values
      5m 14s
    7. Working with boolean values
      5m 13s
    8. Outputting primitive values as strings
      5m 33s
    9. Creating a simple calculator application
      4m 33s
  6. 53m 40s
    1. Writing conditional code
      5m 35s
    2. Using the switch statement
      8m 50s
    3. Repeating code blocks with loops
      7m 35s
    4. Creating reusable code with methods
      6m 31s
    5. Declaring methods with arguments
      5m 41s
    6. Overloading method names with different signatures
      5m 53s
    7. Passing arguments by reference or by value
      5m 35s
    8. Creating a more complex calculator application
      8m 0s
  7. 20m 30s
    1. Using the String class
      5m 44s
    2. Building strings with StringBuilder
      3m 34s
    3. Parsing string values
      3m 19s
    4. Working with date values
      7m 53s
  8. 20m 44s
    1. Understanding compile-time vs. runtime errors
      4m 5s
    2. Handling exceptions with try/catch
      4m 55s
    3. Throwing exceptions in methods
      2m 50s
    4. Using the debugger
      8m 54s
  9. 32m 22s
    1. Using simple arrays
      4m 47s
    2. Using two-dimensional arrays
      6m 17s
    3. Managing resizable arrays with ArrayList
      7m 14s
    4. Managing unordered data with HashMap
      6m 5s
    5. Looping through collections with iterators
      7m 59s
  10. 52m 2s
    1. Understanding encapsulation
      5m 59s
    2. Creating and instantiating custom classes
      8m 8s
    3. Organizing classes with packages
      6m 47s
    4. Creating and using instance methods
      6m 52s
    5. Storing data in instance variables
      6m 56s
    6. Using constructor methods
      5m 40s
    7. Managing instance data with getter and setter methods
      8m 26s
    8. Using class variables and Enum classes
      3m 14s
  11. 41m 15s
    1. Understanding inheritance and polymorphism
      9m 12s
    2. Extending custom classes
      9m 1s
    3. Overriding superclass methods
      3m 8s
    4. Casting subclass objects
      5m 3s
    5. Understanding interfaces and implementing classes
      4m 2s
    6. Creating your own interfaces
      4m 14s
    7. Using abstract classes and methods
      6m 35s
  12. 32m 17s
    1. Managing files with the core class library
      7m 46s
    2. Managing files with Apache Commons FileUtils
      7m 32s
    3. Reading a text file from a networked resource
      7m 52s
    4. Parsing an XML file with DOM
      9m 7s
  13. 17m 39s
    1. Creating your own JAR files
      4m 54s
    2. Understanding the classpath
      5m 2s
    3. Documenting code with Javadoc
      7m 43s
  14. 47s
    1. Goodbye
      47s

Watch this entire course now—plus get access to every course in the library. Each course includes high-quality videos taught by expert instructors.

Become a member
Please wait...
Java Essential Training
7h 17m Beginner Dec 14, 2011

Viewers: in countries Watching now:

Join author David Gassner as he explores Java SE (Standard Edition), the language used to build mobile apps for Android devices, enterprise server applications, and more. This course demonstrates how to install both Java and the Eclipse IDE and dives into the particulars of programming. The course also explains the fundamentals of Java, from creating simple variables, assigning values, and declaring methods to working with strings, arrays, and subclasses; reading and writing to text files; and implementing object oriented programming concepts.

Topics include:
  • Understanding the history and principles of Java
  • Installing Eclipse and Java
  • Compiling and running from the command line
  • Managing memory and performing garbage collection
  • Declaring and initializing variables
  • Writing conditional code
  • Building and parsing strings
  • Debugging and exception handling
  • Using simple arrays
  • Creating custom classes
  • Working with encapsulation, inheritance, and polymorphism
  • Managing files
  • Documenting code with Javadocs
Subjects:
Developer Programming Languages
Software:
Android Java Eclipse
Author:
David Gassner

Managing files with Apache Commons FileUtils

In our previous video, I described how to copy the contents of the text file to a new text file, using tools that are available from the Java class library. I'm working in a copy of that project now called ApacheFileUtils that's a part of the exercise files for this course. In this application, I had to create a whole bunch of different objects two file object representing the existing file and the target file, an input stream and an output stream, a byte array, an integer, and then I had to loop through and read the file one set of bytes at a time and write out the new file.

To all new Java developers, this seems a bit cumbersome and almost everybody asks the question isn't there an easier way. The reality of the Java class library is that it tends to give you tools in very small pieces, and it's up to you the developer to figure out how to plug those tools together to get your work done, but the good news is that the Java programming language has been around a long time and the Java developer community has done a great job figuring out what were the most common tasks that everybody needs to do and those tasks tend to be encapsulated and delivered in a project called the Apache Commons.

You can get to the Apache Commons website at http://commons.apache.org. This project contains fully tested reusable Java components that are completely free and licensed for use on either Open Source or commercial applications, most of the components in the Apache Commons can be used in any Java development environment including console applications like the ones I've been showing here, but also including Java Enterprise Edition applications that is web applications and Android mobile applications.

To get to the Commons project we need, go to the Commons Proper from the homepage, you'll see that there are a whole bunch of different projects you can work with and we're going to work with this collection IO. On the IO page, you can click into utility classes and then scroll down in the list of classes, and you'll see a class listed there called File Utils. This is the class, that I'll be working with. The first step to using the class is to download the Commons IO package, I'll go back a couple steps in my browser, back to the IO page and in the Commons IO menu on the left, you'll click the download link.

There are two binary versions of the download a tar.gz version and zipped version. The zipped version should work fine for either Windows or Mac. Now, I've already downloaded and extracted the file to my desktop, I'll open the extracted folder and drill down, until I see these files. The zip file contains three jar files, I don't need the Java docs and I don't need the source files, what I need are the binaries, they will have a file extension of dot jar and the name commons-io and the version number.

I'm using version 2.1 but any later version should work pretty much the same. Now, to use this file in your project copy it to the clipboard then go to the folder that contains your project, I'm using Windows so I'll use Windows Explorer and I'll go to the 11 files folder and from there to ApacheFileUtils, now you can place this file anywhere on your disk you want to, but most Java developers place existing libraries into a folder named Lib, L-I-B.

So I'll create a new folder and I'll name it Lib or Lib or L-I-B, I'll drill down into that folder and paste the jar file, then I'll switch back to Eclipse. I'll go to the Package Explorer and refresh the view and show that the Lib folder and the jar file are now there. Now here's how you incorporate the jar file into your application, you have to add the jar file to something called the build path. A new Java project always includes these jar files that are a part of the Java runtime environment system library something I sometimes refer to as the Java class library.

You're adding your own jar file to the build path and here is the easiest way to do it. Right click on the jar file, choose Build Path, Add to Build Path and now, all the classes that are in that jar file are available to your project. Now we're going to replace some of the existing code, I'll double-click the editor to expand it to full screen and then I'm going to select starting at the input stream declaration and ending at the close calls. You're still going to need to create references to your files, the source file and the target file, but all this other more complex code won't be needed anymore you can just delete it.

Next, I'll call a method of the file utils class that's a member of the Apache Commons Library that I added to my project's build path. The particular method I need is a class method or a static method. So I'm going to call it directly from the class library, it'll be FileUtils. and here is a whole list of everything you're able to do with the class library, including copying files, getting directory information, moving files, reading files, and writing files.

And I'm going to use a method called copy file. There are a few different versions of it, it's an overloaded method but I'm going to use this version that accept two file references. There are two required methods, the source and destination. I'll set the first to f1 and the second to f2 and that's it, that's all the code I need. I remove these TODO commons because I really don't need to do anything else, I'll save and run the application and I get the message file copied.

I'll go back to my Package Explorer and I'll Refresh and I see my new target file has been successfully created. Now the magic of the Apache Commons approach is that you eliminate a whole bunch of complexity from your application, you'll notice that my application is showing these warnings about all the import statements my file still has but I'm not using. These are all the classes that were required when I was using the Java class library approach, that is, I was limiting myself to using only the tools that are available in the JRE.

But when you expand your world to include the Apache Commons, life gets a whole lot easier, I'm going to organize my imports by choosing Source > Organize Imports, and now I see that the only classes I'm using are the File class and the Exception classes. The code within the Commons class still might throw those exceptions, so I still need to refer to them but everything else is greatly simplified. I strongly encourage you to take a look through the documentation for the Apache Commons Libraries, for example, in the IO page, there's a link for the Java doc for version 2.1 and the class that we are using FileUtils has a listing of all the methods that are available, but you'll also see that there are dozens and dozens of other classes available.

And this is just one of the projects in Apache Commons, using the Apache Commons project can make your coding much simpler and your process of learning Java and making it useful for your applications a lot faster.

There are currently no FAQs about Java Essential Training.

Share a link to this course
Please wait... Please wait...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.
Upgrade now


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Upgrade now

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Java Essential Training.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Welcome to the redesigned course page.

We’ve moved some things around, and now you can



Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked