java 11 read file line by line

In Java 11 and later, you can use the Files.lines method of the java.nio.file.Files class to read a file line by line.

To use the Files.lines method to read a file line by line, you can use the following syntax:

try (Stream<String> stream = Files.lines(Paths.get("file.txt"))) {
    stream.forEach(System.out::println);
} catch (IOException e) {
    // handle I/O exception
}

Here, file.txt is the name of the file to be read, and stream is a Stream of String objects representing the lines of the file.

The Files.lines method returns a Stream of String objects that can be processed using the Stream API.

In this example, the forEach terminal operation is used to iterate over the lines of the file and print them to the console.

It is important to note that the Files.lines method reads the file lazily, which means that the file is not read until the Stream is consumed.

This allows you to process the lines of the file efficiently and consume only the lines that you need.

It is also important to note that the Files.lines method throws an IOException if an I/O error occurs while reading the file.

Therefore, it is recommended to use the try-with-resources statement to ensure that the Stream is closed properly, and to catch any IOException that may be thrown.

Alternatively, you can use the BufferedReader class to read a file line by line, like this:

String filepath = "test.txt";
File fp = new File(filepath);
FileReader fr = new FileReader(fp);
BufferedReader br = new BufferedReader(fr);

ArrayList<String> lines = new ArrayList<>();
String line;
while ((line = br.readLine()) != null) {
    lines.add(line);
}

fr.close();
System.out.println("lines:" + lines);