How do I do a HTTP GET in Java?

2

4 Answers

If you want to stream any webpage, you can use the method below.

import java.io.*; import java.net.*; public class c { public static String getHTML(String urlToRead) throws Exception { StringBuilder result = new StringBuilder(); URL url = new URL(urlToRead); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); try (BufferedReader reader = new BufferedReader( new InputStreamReader(conn.getInputStream()))) { for (String line; (line = reader.readLine()) != null; ) { result.append(line); } } return result.toString(); } public static void main(String[] args) throws Exception { System.out.println(getHTML(args[0])); } }
9

Technically you could do it with a straight TCP socket. I wouldn't recommend it however. I would highly recommend you use Apache HttpClient instead. In its simplest form:

GetMethod get = new GetMethod(""); // execute method and handle any error responses. ... InputStream in = get.getResponseBodyAsStream(); // Process the data from the input stream. get.releaseConnection();

and here is a more complete example.

1

If you dont want to use external libraries, you can use URL and URLConnection classes from standard Java API.

An example looks like this:

String urlString = ""; URL url = new URL(urlString); URLConnection conn = url.openConnection(); InputStream is = conn.getInputStream(); // Do what you want with that stream
4

The simplest way that doesn't require third party libraries it to create a URL object and then call either openConnection or openStream on it. Note that this is a pretty basic API, so you won't have a lot of control over the headers.