05. Readers & Writers

Readers and Writers

In this section, you will learn how to read and write character data using the Reader and Writer abstract classes.

Readers / Writers

Readers and Writers are the next level of abstraction built on top of input and output streams. These interfaces read and write text characters.

Reader Example

char[] data = new char[10];
Reader reader =
   Files.newBufferedReader(Path.of("test"), StandardCharsets.UTF_8);
while (reader.read(data) != -1) {
 useData(data);
}
reader.close();

Just like input streams, Readers are usually created with the Files API. But instead of reading bytes, we are reading chars. There's also a StandardCharset, which we'll cover that in more detail in the next video.

Writer Example

Writer writer =
   Files.newBufferedWriter(Path.of("test"),
                           StandardCharsets.UTF_8);
writer.write("hello, world");
writer.close();  // Close the "test" file

The Writer is pretty much what you would expect. This time we are writing encoded Strings of data instead of raw bytes.

If you're just itching to see a coding demo using readers and writers, rest assured there's one on the very next page! I decided to save the demo for the discussion on character encodings.

Further Reading

• Reader JavaDoc
• Writer JavaDoc