File Handling in Java

Java provides classes in java.io and java.nio.file to read and write data in files persistently.

Writing to a file

We use FileWriter and BufferedWriter for better efficiency.

try (BufferedWriter writer = new BufferedWriter(new FileWriter("archivo.txt"))) {
    writer.write("Hello, this is a line of text.");
    writer.newLine();
    writer.write("Learning Java!");
} catch (IOException e) {
    e.printStackTrace();
}

Reading from a file

We use FileReader and BufferedReader.

try (BufferedReader reader = new BufferedReader(new FileReader("archivo.txt"))) {
    String line;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }
} catch (IOException e) {
    e.printStackTrace();
}

The try-with-resources block

Notice that in the previous examples we used try (...). This is an excellent practice in Java that ensures the file is closed automatically at the end, even if an error occurs, avoiding memory leaks.