Read and Write a File Line by Line in Java 8

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.util.Arrays; import java.util.List;   public class FileTest {    public static void main(String[] args) throws IOException  {       Path pathToRead = Paths.get("C:\\...\\dataIn.csv");       // Check if file exists   if(!Files.exists(pathToRead)) {    System.out.println("file doesn't exist :-(");    return;   };       // read a file line by line   Files.lines(pathToRead).forEach(line -> {    // Process the String line here!!    System.out.println(line);   });       // write a file line by line   List<String> lines = Arrays.asList("line 1", "line 2", "line 3");   Path pathToWrite = Paths.get("C:\\...\\dataOut.csv");   Files.write(pathToWrite, lines);  } }

In Files.write() you can use also add Options, e.g. StandardOpenOption.CREATE or StandardOpenOption.APPEND. If omitted like above you get StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING.

More options to read/write also larger files in a buffered way are found here https://www.baeldung.com/java-read-file