How to set append options and StandardCharsets/Encoding to BufferedWriter in java?

Question

I am new to java programming and looking for options to write and append file content with java.

Similar options for below C# options.

File.WriteAllText(string path, string contents, Encoding encoding);
File.AppendAllText(string path, string contents, Encoding encoding);

I though to use BufferedWriter, it have option to pass true/false for FileWriter(String path, boolean append) but i don't have option to provide Encoding.

try (FileWriter fw = new FileWriter(path, false);
    BufferedWriter bw = new BufferedWriter(fw)) {
    bw.write("appending text into file");
}

If I initialize BufferedWriter with Files.newBufferedWriter, I can provide StandardCharsets, but it don't have option to append in case of existing file.

try (BufferedWriter bw = Files.newBufferedWriter(Paths.get(path), StandardCharsets.UTF_8)) {
    bw.write("test");
    bw.append("append test");
}

Is it possible to define both option together (Append options and StandardCharsets)?

Possible duplicate of [Appending to file in utf8](https://stackoverflow.com/questions/45614345/appending-to-file-in-utf8) — Olf, Jan 15 '19 at 13:41
@Olf Although it is similar, this question is about `Files.newBufferedWriter`. — Mark Rotteveel, Jan 15 '19 at 18:51

score 1 · Accepted Answer · answered Jan 15 '19 at 13:43

Yes. if you look into the Files class implementation, there is a method as follows:

public static BufferedWriter newBufferedWriter(Path path, Charset cs, OpenOption... options)

so you can call a method like

BufferedWriter bw = Files.newBufferedWriter(Paths.get(path), StandardCharsets.UTF_8, 
                    StandardOpenOption.CREATE, StandardOpenOption.APPEND)

If you use a IDE like Intellij, it would suggest what public methods you are allowed to call.

Thank you, I was looking for same and it worked for me. – Krupa Jan 15 '19 at 16:23 — Krupa, Jan 15 '19 at 16:23

score 0 · Answer 2 · answered Jan 15 '19 at 13:46

You can give a try to java.nio in order to append content to an existing file (if you are using Java 7 or above), maybe you can do something like this:

List<String> newContent = getNewContent(...); // Here you get the lines you want to add
Files.write(myFile, newContent, UTF_8, APPEND, CREATE);

The imports will need to be done by:

java.nio.charset.StandardCharsets.UTF_8, java.nio.file.StandardOpenOption.APPEND, java.nio.file.StandardOpenOption.CREATE

Or you can try using Guava:

File myFile = new File("/Users/home/dev/log.txt");
String newContent = "This is new content";
Files.append(newContent, myFile, Charsets.UTF_8);

How to set append options and StandardCharsets/Encoding to BufferedWriter in java?

2 Answers2