java - 字节流读取文件

package stream;

import java.io.*;

public class InputStreamReaderString {

    public static void main(String[] args)  {

        File f = new File("src/stream","hello.txt");

        try(FileInputStream fis = new FileInputStream(f)){

            byte[] all = new byte[(int)f.length()];

            fis.read(all);

            String str = new String(all);

            System.out.println(str);

        }catch(IOException e) {
            e.printStackTrace();
        }

    }

}