Java | 两个IO实例demo

最新推荐文章于 2022-09-26 22:01:57 发布

原创最新推荐文章于 2022-09-26 22:01:57 发布 · 239 阅读

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CC 4.0 BY-SA版权

本文介绍了使用HttpURLConnection发送GET请求获取网络资源的方法，并详细展示了如何将网络响应转化为字符串的过程。此外，还提供了BlockCanary中文件写入的具体实现，包括路径选择、目录创建和日志保存的完整流程。

套路：.
字节流（如InputStream ）转换成字符流（如InputStreamReader），
字符流转成缓冲字符流（如BufferedReader）；
缓冲字符流（如BufferedReader）直接拿去读写；

Url网络响应输入流

private void sendRequestWithHttpURLConnection() {

        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection connection = null;
                BufferedReader reader = null;

                try {
                    URL url = new URL("https://hao.360.cn/");
                    connection = (HttpURLConnection)url.openConnection();

                    connection.setRequestMethod("GET");

                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);

                    InputStream in = connection.getInputStream();

                    //下面对获取的输入流进行读取
                    //InputStreamReader赋值给BufferedReader让其来读
                    reader = new BufferedReader(new InputStreamReader(in));
                    StringBuilder response = new StringBuilder();
                    String line;
                    //一行一行地读取并加进stringbuilder
                    while((line = reader.readLine()) != null){
                        response.append(line);
                    }
                    showResponse(response.toString());
                    Log.d("NetworkTest:  ", response.toString());
                } catch (IOException e) {
                    e.printStackTrace();
                }finally{
                    if(reader !=null){
                        try {
                            reader.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if(connection !=null){
                        connection.disconnect();
                    }
                }
            }
        }).start();

    }

BlockCanary的文件流【写入文件】

BlockCanaryInternals.java

    static String getPath() {
        String state = Environment.getExternalStorageState();
        String logPath = BlockCanaryInternals.getContext()
                == null ? "" : BlockCanaryInternals.getContext().providePath();

        if (Environment.MEDIA_MOUNTED.equals(state)
                && Environment.getExternalStorageDirectory().canWrite()) {
            return Environment.getExternalStorageDirectory().getPath() + logPath;
        }
        return Environment.getDataDirectory().getAbsolutePath() + BlockCanaryInternals.getContext().providePath();
    }

    static File detectedBlockDirectory() {
        File directory = new File(getPath());
        if (!directory.exists()) {
            directory.mkdirs();
        }
        return directory;
    }

---------------------------------------------------------------------------------
//LogWriter.java

private static String save(String logFileName, String str) {
        String path = "";
        BufferedWriter writer = null;
        try {
            File file = BlockCanaryInternals.detectedBlockDirectory();
            long time = System.currentTimeMillis();
            path = file.getAbsolutePath() + "/"
                    + logFileName + "-"
                    + FILE_NAME_FORMATTER.format(time) + ".log";

            OutputStreamWriter out =
                    new OutputStreamWriter(new FileOutputStream(path, true), "UTF-8");

            writer = new BufferedWriter(out);

            writer.write(BlockInfo.SEPARATOR);
            writer.write("**********************");
            writer.write(BlockInfo.SEPARATOR);
            writer.write(TIME_FORMATTER.format(time) + "(write log time)");
            writer.write(BlockInfo.SEPARATOR);
            writer.write(BlockInfo.SEPARATOR);
            writer.write(str);
            writer.write(BlockInfo.SEPARATOR);

            writer.flush();
            writer.close();
            writer = null;

        } catch (Throwable t) {
            Log.e(TAG, "save: ", t);
        } finally {
            try {
                if (writer != null) {
                    writer.close();
                }
            } catch (Exception e) {
                Log.e(TAG, "save: ", e);
            }
        }
        return path;
    }