File newFile = new File("D:/io.txt");

        FileReader readerStream = null;

        FileWriter writerStream = null;

        try {

            if (newFile.createNewFile()) {

                System.out.println("文件创建成功");

            } else {

                System.out.println("文件创建已存在");

            }

            readerStream = new FileReader(newFile);

            int read = -1;

            while ((read = readerStream.read()) != -1) {

                System.out.print((char) read);

            }

            writerStream = new FileWriter(newFile, true);

            writerStream.write("Tttttt");

            writerStream.flush();

            System.out.println("写入完成，重新读取。。。");

            BufferedReader bReader = new BufferedReader(readerStream);

            System.out.println(bReader.readLine() + "--");

            bReader.close();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        } finally {

            try {

                readerStream.close();

                writerStream.close();

            } catch (IOException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

        }