It's a complex question, but I'll try to summarize what each one does and what it does according to the documentation.
1 - HttpURLConnection
This is an abstract class that contains the methods used to make a HTTP connection. It extends the class URLConnection .
Usage example:
URL url = new URL("http://teste.com");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestMethod("GET");
conn.setDoInput(true);
conn.connect();
See for example that to get an instance of type HttpURLConnection, we have to instantiate the URL class. If you check the documentation, the URL class represents "Uniform Resource Locator," a note to a Web site.
After the URL class is instantiated, it is the HttpURLConnection class that will be responsible for connecting to this named place.
2 - OutputStream
Used when you need to write data to somewhere, be it a file, network connections, etc. In this case, it is used to write the data in a HTTP connection.
Usage example:
// Antes de você escrever os dados, você precisa dizer a conexão que você vai fazer isso
conn.setDoOutput(true);
// Instancia o OutputStreamWriter usando o OutputStream da conexão que você efetuou
OutputStreamWriter writer = new OutputStreamWriter(
conn.getOutputStream());
// Escreve os dados para a conexão.
// Nenhum dado é escrito até que você utilize este método.
writer.write("message=" + message);
3 - InputStream \ BufferedReader
It is the opposite of OutputStream , it serves to read (read) the data from somewhere. In this case it is used to establish a read contract with the connection HTTP .
Usage example:
BufferedReader reader = new BufferedReader(conn.getInputStream());
StringBuilder result = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
result.append(line);
}
System.out.println(result.toString());
Following the example above, it reads the response in a string using the BufferedReader class, so it is used to read data from InputStream .
That said, you can already pull out what the class BufferedWriter would serve, would the opposite of BufferedReader .
Aside from the android documentation, you can take a look at this community link in English.
