Great, thanks. I am reading files byte by byte now with DataInputStream. You simply write the bytes to a FileOutputStream which refers to that file.
Don't forget to close the file after you finish. And by the way, there are two rules about when to use the "available" method of an InputStream: 1 Don't use it unless you know what it does. What was the reason you chose to use DataInputStream? Why are you casting the bytes that you read from the file to char and print them to the console window line 31? This will lead to gibberish output on the console. You could read the content of the file into a byte array, like in this example.
This example shows how to copy a file by reading blocks of data from a FileInputStream and writing those blocks to a FileOutputStream.
It only has static utility methods for working with files and directories. The readAllLines method that uses the default character encoding was introduced in jdk1. This code was tested to work in Java 8 and 9.
Just like in the previous example, this code was tested and works in Java 8 and 9 but not in Java 7. The Scanner class was introduced in jdk1. Apache Commons IO is an open source Java library that comes with utility classes for reading and writing text and binary files. I listed it in this article because it can be used instead of the built in Java libraries.
Note that you need to explicitly specify the encoding and that method for using the default encoding has been deprecated. Google Guava is an open source library that comes with utility classes for common tasks like collections handling, cache management, IO operations, string processing.
I listed it in this article because it can be used instead of the built in Java libraries and I wanted to compare its performance with the Java built in libraries.
For this article, version When reading a file, Guava requires that the character encoding be set explicitly, just like Apache Commons. Compatibility note: This code was tested successfully on Java 8 and 9. I thought I could get it to work but I kept getting that error.
Each code sample from this article displays the contents of the file to a string and then to the console System. However, during the performance tests the System. Each performance test measures the time it takes to read in the file — line by line, character by character, or byte by byte without displaying anything to the console.
I ran each test times and took the average so as not to let any outliers influence each test. I also ran the default encoding version of each file reading method — i. Random String Generator was used to generate sample text and then I simply copy-pasted to create larger versions of the file.
When the file started getting too large to manage inside a text editor, I had to use the command line to merge multiple text files into a larger text file:. I created the following 7 data file sizes to test each file reading method across a range of file sizes:. Lastly, print the string. Exceptions: ArgumentException: The path is a zero-length string, contains only white space, or one or more invalid characters as defined by InvalidPathChars.
ArgumentNullException: The path is null. PathTooLongException: The specified path , file name, or both exceed the system-defined maximum length. DirectoryNotFoundException: The specified path is invalid. UnauthorizedAccessException: This operation is not supported on the current platform. OR the path specified a directory. OR the caller does not have the required permission.
FileNotFoundException: The file specified in the path was not found. NotSupportedException: The path is in an invalid format.
SecurityException: The caller does not have the required permission. Skip to content. Change Language. Related Articles. I started this blog as a place to share everything I have learned in the last decade. I write about modern JavaScript, Node. The newsletter is sent every week and includes early access to clear, concise, and easy-to-follow tutorials, and other stuff I think you'd enjoy!
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