How to write file using Files.newBufferedWriter?

To open a file for writing in JDK 7 you can use the Files.newBufferedWriter() method. This method takes three arguments. We need to pass the Path, the Charset and a varargs of OpenOption.

For example, in the snippet below we pass the path of our log file, we use the StandardCharsets.UTF_8 charset, and we use the StandardOpenOption.WRITE to open a file for writing. If you want to open a file and append its contents instead of rewriting it you can use the StandardOpenOption.APPEND.

package org.kodejava.io;

import java.io.BufferedWriter;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

public class FilesNewBufferedWriter {
    public static void main(String[] args) throws Exception {
        Path logFile = Paths.get("app.log");
        if (Files.notExists(logFile)) {
            Files.createFile(logFile);
        }

        try (BufferedWriter writer =
                     Files.newBufferedWriter(logFile, StandardCharsets.UTF_8,
                             StandardOpenOption.WRITE)) {

            for (int i = 0; i < 10; i++) {
                writer.write(String.format("Message %s%n", i));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Because we use the StandardOpenOption.WRITE we have to make sure that the file to be written is exists. If the file is not available we will get error like java.nio.file.NoSuchFileException.

Wayan

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