Java如何用WriteUTF写文件，ReadUTF读文件

直接上样例参考（附有部分说明）：

File fileName = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/test/test.levp");
                FileOutputStream fileOutputStream=null;
                DataOutputStream dataOutputStream=null;
                try {
                    fileOutputStream = new FileOutputStream(fileName);
                    dataOutputStream = new DataOutputStream(fileOutputStream);
                    dataOutputStream.writeUTF("第1句话。");
                    dataOutputStream.writeUTF("第2句话。");
                    dataOutputStream.writeUTF("第3句话。");
                    dataOutputStream.writeUTF("第4句话。");
                    …………………………………………………………………………
                    dataOutputStream.flush();
                    fileOutputStream.close();
                    dataOutputStream.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    try {
                        fileOutputStream.close();
                        dataOutputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                StringBuilder content = new StringBuilder();
                FileInputStream fileInputStream = null;
                DataInputStream dataInputStream = null;
                try {
                    fileInputStream = new FileInputStream(fileName);
                    dataInputStream = new DataInputStream(fileInputStream);
                    while (true) {
                        content.append(dataInputStream.readUTF()+ "\n");//by throwing java.io.EOFException to get the Reading result（目前，ReadReadUTFT还没有现判断文件读完的方法，可通过文件读到底发生异常来处理相关数据或目的）
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();//探测发生文件读完的异常后，程序跳转至此处进行处理（也可以在处设置相关目标代码），最后跳转finally处
                } finally {
                    tv_Sample.setText(content);//实现如在设置的TextView中显示等目的
                    try {
                        fileInputStream.close();
                        dataInputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }