Java URL Class

What is the use of URL class?

URL class is used to uniquely identify or address information on the Internet.
URL class provides a simple API to access URL's information across the Internet.
MalformedURLException may be thrown in URL class constructor's.

URL(String url)

How to get URL information in java program?

//Gets the URL information using URL Class in java.
import java.net.*;                                                              
                                                                                
class URLTest {                                                                 
public static void main(String args[]) throws MalformedURLException {           
//Creates URL object
URL url = new URL("https://www.codingpointer.com");                             
                           
//Prints URL details using URL Class methods.                                                     
System.out.println("External link: " + url.toExternalForm());                   
System.out.println("Protocol: " + url.getProtocol());                           
System.out.println("Host: " + url.getHost());                                   
System.out.println("Port: " + url.getPort());                                   
System.out.println("File: " + url.getFile());                                   
}                                                                               
}                                                                               

Output:

External link: https://www.codingpointer.com
Protocol: https
Host: www.codingpointer.com
Port: -1
File: 

What is the use of URLConnection class?

URLConnection class is used to access content information in URL.
url.openConnection() method returns URLConnection object.

import java.net.*;                                                              
import java.util.Date;                                                          
                                                                                
class URLConnectionTest {                                                       
 public static void main(String args[]) throws Exception {                      
  URL url = new URL("https://www.codingpointer.com");                           
                                                                                
  URLConnection con = url.openConnection();                                     
                                                                                
  long dateInfo = con.getDate();                                                
  if(dateInfo != 0) {                                                           
   System.out.println("Created Date: " + new Date(dateInfo));                   
  }                                                                             
                                                                                
  System.out.println("Content-Type: " + con.getContentType());                  
  dateInfo = con.getExpiration();                                               
  if(dateInfo != 0) {                                                           
   System.out.println("Expiration Date: " + new Date(dateInfo));                
  }                                                                             
                                                                                
  dateInfo = con.getLastModified();                                             
  if(dateInfo != 0) {                                                           
   System.out.println("Last Modified Date: " + new Date(dateInfo));             
  }                                                                             
                                                                                
  System.out.println("Content Length: " + con.getContentLength());              
 }                                                                              
}   

Output:

Created Date: Sun Aug 20 14:23:32 IST 2017
Content-Type: text/html; charset=UTF-8
Content Length: -1

How to get content of any web page using URLconnection Class object?

To get the html content of the web page, we can use con.getInputStream() method.

URL url = new URL("https://www.codingpointer.com");                                                                                                         
URLConnection con = url.openConnection();
InputStream ins = con.getInputStream();
int ch;
while(true) {
 ch = ins.read();
  if(ch == -1)
   break;
  System.out.println((char) ch);
}

ins.close();

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