HTTP URL

HttpURLConnection :
Java provides a subclass of URLConnection that provides support for HTTP connections. This class is called HttpURLConnection. You obtain an HttpURLConnection in the same way just shown, by calling openConnection() on a URL object, but you must cast the result to HttpURLConnection. you can also use any of the several Methods defined by HttpURLConnection.

static boolean getFollowRedirects()	Returns true if redirects are automatically followed and false otherwise. This feature is on by default.
String getRequestMethod()	Returns a string representing how URL requests are made. The default is GET. Other options, such as Post, are available.
int getResponseCode() throws IOException	Returns the HTTP response code -1 is returned if no response code can be obtained. As IOException is thrown if the connection fails.
String getResponseMessage() throws IOException	Returns the response message associated with the response code. Returns NULL if no message is available. An IOException is throws if the connection fails.
static void setFollowRedirects(boolean how)	if how is true, then redirects are automatically followed. if how is false, redirects are not automatically followed. By default, redirects are automatically followed.
void setRequestMethod(String how) throws ProtocolException	Set the method by which HTTP requests are made to that specified by how. the default method is GET, but other options, such as POST, are available. if how is invalid, a ProtocolException is thrown.

The Following program demonstrates HttpURLConnection. It first establishes a connection to "www.a143mkblogspot.in". Then it displays the request method, the response code and The Response Message.

import java.net.HttpURLConnection; import java.net.URL; import java.util.List; import java.util.Map; import java.util.Set; /** * * @author Manoj */ public class HttpURLDemo { /** * @param args the command line arguments */ public static void main(String[] args) throws Exception { URL u=new URL("http://www.a143mk.blogspot.in"); HttpURLConnection u_con=(HttpURLConnection) u.openConnection(); //Display the Request Method. System.out.println("Request Method is :" +u_con.getRequestMethod()); //Display the Response Code. System.out.println("Response Code is : " + u_con.getResponseCode()); //Display the Response Message. System.out.println("Response Message is : " + u_con.getResponseMessage()); //Get a list of the header fields and a set of header keys. Map<String, List<string>> hdrMap=u_con.getHeaderFields(); Set<string> hdrField=hdrMap.keySet(); System.out.println("\n Here is the Header :"); //Display all header keys and values. for(String k:hdrField){ System.out.println("Key : " +k + "Values" +hdrMap.get(k)); } } }

Out Put: