How do I retrieve a URL from a web site using Java

问题:

I want to use HTTP GET and POST commands to retrieve URLs from a website and parse the HTML. How do I do this?

回答1:

You can use HttpURLConnection in combination with URL.

URL url = new URL("http://example.com");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("GET");
connection.connect();

InputStream stream = connection.getInputStream();
// read the contents using an InputStreamReader

回答2:

The easiest way to do a GET is to use the built in java.net.URL. However, as mentioned, httpclient is the proper way to go, as it will allow you among others to handle redirects.

For parsing the html, you can use html parser.

回答3:

The ticked/approved answer for this is from robhruska - thank you. This shows the most basic way to do it, it's simple with an understanding of what's necessary to do a simple URL connection. However, the longer term strategy would be to use HTTP Client for more advanced and feature rich ways to complete this task.

Thank you everyone, here's the quick answer again:

URL url = new URL("http://example.com");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("GET");
connection.connect();

InputStream stream = connection.getInputStream();
// read the contents using an InputStreamReader

回答4:

Use http://hc.apache.org/httpclient-3.x/

回答5:

I have used JTidy in a project and it worked quite well. A list of other parsers is here, but besides from JTidy I don't know any of them.