Android downloads the file to the specified directory implementation code

/**
    * Download the file with the specified path and write it to the specified location
    *
    * @param dirName
    * @param fileName
    * @param urlStr
    * @return Return 0 means downloading is successful, return 1 means downloading error
    */
  public int downloadFile(String dirName, String fileName, String urlStr) {
    OutputStream output = null;
    try {
      //Convert the path in the form of a string into a url      URL url = new URL(urlStr);
      //After getting the url, you will start connecting to the network, thinking it is the specific code for connecting to the network      //First, instantiate an HTTP connection object conn      HttpURLConnection conn = (HttpURLConnection) ();
      //Define the request method as GET, and do not make mistakes in case of GET.      ("GET");
      //Define the request time, it is best not to exceed 10 seconds in ANDROID.  Otherwise it will be recycled by the system.      (6 * 1000);
      //After the request is successful, the server will return a response code.  If it is a GET request, the response code returned by the server is 200, and the response code returned by the post request server is 206 (seemingly).      if (() == 200) {
        //The return code is true        //The data passed from the server is an input action.  Define an input stream to get the data returned from the server        InputStream input = ();
        File file = createFile(dirName + fileName);
        output = new FileOutputStream(file);
        //Read large files        byte[] buffer = new byte[1024];
        //Record the reading content        int n = (buffer);
          //Write to file          (buffer, 0, n);
          n = (buffer);
        }
        ();
         ();
      }
    } catch (MalformedURLException e) {
      ();
    } catch (Exception e) {
      ();
    } finally {
      try {
        ();
        ("success");
        return 0;
      } catch (IOException e) {
        ("fail");
        ();
      }
    }
    return 1;
  }
  /**
    * Create a file on the specified directory of the SD card
    *
    * @param fileName
    */
  public File createFile(String fileName) {
    File file = new File(fileName);
    try {
      ();
    } catch (IOException e) {
      ();
    }
    return file;
  }