Android 类似于记录Log日志

文件保存在app下，主要是创建文件、续写内容、读取内容的实现思路。最后可以通过okhttp3或者Retorfit实现与服务器交互，post上送文件。

    private String filename = Environment.getExternalStorageDirectory().getCanonicalPath() + "/" + "2.txt";

// 运行方法
    private void saveAppendMessage() {
        createFile(filename);
        writeData(filename, "weqweqwe12321321312");
        bufferRead(filename);
    }

//创建文件
    private void createFile(String fileURL) {
        File logFile = new File(fileURL);
        // Make sure log file is exists
        if (!logFile.exists()) {
            boolean result = false; // 文件是否创建成功
            try {
                result = logFile.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (result) {
                Log.e("chenxh", "");
            }
        } else {
            Log.e("chenxh", "文件已存在");
        }
    }
//续写内容
    private boolean writeData(String fileURL, String message) {
        File file = new File(fileURL);
        RandomAccessFile raf = null;
        try {
            //如果为追加则在原来的基础上继续写文件
            raf = new RandomAccessFile(file, "rw");
            raf.seek(file.length());
            raf.write(message.getBytes());
            raf.write("\n".getBytes());
            Log.e("chenxh", "写入成功");
        } catch (IOException e) {
            e.printStackTrace();
        }
        return true;
    }
//读取文件内容
    public void bufferRead(String filename) {
        try {
            BufferedReader bfr = new BufferedReader(new FileReader(new File(filename)));
            String line = bfr.readLine();
            StringBuilder sb = new StringBuilder();
            while (line != null) {
                sb.append(line);
                sb.append("\n");
                line = bfr.readLine();
            }
            bfr.close();

            Log.e("chenxh", "bufferRead: " + sb.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }