So instead of creating unhelpful try catch blocks that just print exception stack traces and clutter up the code, all example will declare any checked exception in the calling method.
This will make the code cleaner and easier to understand without sacrificing any functionality. FileReader reads in one character at a time, without any buffering. It uses the default character encoding on your system, so I have provided examples for both the default case, as well as specifying the encoding explicitly.
BufferedReader reads an entire line at a time, instead of one character at a time like FileReader. In a similar way to how we set encoding explicitly for FileReader, we need to create FileInputStream , wrap it inside InputStreamReader with an explicit encoding and pass that to BufferedReader:.
FileInputStream reads in one byte at a time, without any buffering. By default, it uses the default character encoding on your system, so I have provided examples for both the default case, as well as specifying the encoding explicitly.
BufferedInputStream reads a set of bytes all at once into an internal byte array buffer. The default buffer size appears to be 8KB but I have not explicitly verified this. All performance tests used the default buffer size so it will automatically re-size the buffer when it needs to. 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. Show us the IO code. Add a comment. Active Oldest Votes. Improve this answer. Victor Sorokin Victor Sorokin And for reading back? Does it automatically know the length of the bytes to read?
For reading back use FileInputStream and it's method avialable. Read javadoc at: docs. I did this: I write the size of the byte array before the actual content of the array. It works like a charm. Danilo Valente Kevin Bigler Kevin Bigler 1 1 gold badge 2 2 silver badges 9 9 bronze badges. Not that I necessarily disagree, but this doesn't answer the question. This would be better as a comment on the original question than an answer. Oh sorry I'm new to this site. At any rate, "I think I should use binary files for this please correct me if I am wrong.
Sorry about that. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Files ; import java. Path ; import java. Download Code. FileOutputStream is meant for writing streams of raw bytes such as image data. File ; import java. FileOutputStream ; import java. We can use a data output stream to write the string to the underlying output stream as a bytes sequence. If the file already exists, then the file will be truncated before writing.
FileUtils ; import java. To write large binary files, use FileChannel. RandomAccessFile ; import java. ByteBuffer ; import java. FileChannel ; import java. Write to a file in Java. Vote count:
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