如何获取给定字符串的文件大小？

Question

If we had a string and we put that string into a text file... that text file would have a size. Is there some sort of formula that we could use to calculate the size? I really need to do this because turning the string into a text file and getting the size then deleting the file is not working.

Answer 1

Example using java.nio.Files :

public static long getStringSize(String str) throws IOException {
    Path file = Path.of("niofiles.txt");
    Files.writeString(file, str, StandardOpenOption.CREATE_NEW);
    long size = Files.size(file);
    Files.deleteIfExists(file); // cleanup
    return size;
}

Example using java.io.File :

public static long getStringSizeFile(String str) throws IOException {
    File file = new File("iofile.txt");
    try (BufferedWriter bw = new BufferedWriter(new FileWriter(file))) {
        bw.write(str);
    }
        
    long size = file.length();
    file.delete(); // cleanup
    return size;
}

Even simpler example to use length of the byte array:

public static int stringSize(String str) {
    return str.getBytes().length;
}

Answer 2

All you need is to count bytes required to store you string, because one character could take more than one byte.

When you write n bytes to the file, this file is going to have exactly this amount of bytes. Do use String.getBytes() to calculate it.

public static void main(String... args) {
    String str = "endereço";
    System.out.println(str.length());                            // 8
    System.out.println(str.getBytes(StandardCharsets.UTF_8));    // 9
}