java操作文件

优雅读取文件

 List<String> lines = Files.readAllLines(Paths.get("/Users/cong/3.txt"), StandardCharsets
                .UTF_8);

优雅的写入文件

 PrintStream out = new PrintStream(newFileOutputStream("/Users/cong/Desktop/pass/passwd.txt"));
 out.println(stringBuilder.toString());

读取大文件

   try {


            FileChannel fileChannel = FileChannel.open(Paths.get("/Users/cong/Downloads/crackstation-human-only.txt"), StandardOpenOption.WRITE, StandardOpenOption.READ, StandardOpenOption.CREATE);

            MappedByteBuffer mbb = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, 900);
            Charset charset = Charset.forName("utf-8");
            CharsetDecoder decoder = charset.newDecoder();
            CharBuffer charBuffer = decoder.decode(mbb);
            Scanner sc = new Scanner(charBuffer).useDelimiter(System.getProperty("line.separator"));
            while (sc.hasNext()) {
                String next = sc.next();
                System.out.println(next);


            }

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