EXCEPTION HANDLING AND TEXT I/O - Introduction to Java Programming - page 552

3 public class ReadFileFromURL {
4 public static void main(String[] args) {
5 System.out.print( "Enter a URL: " );
6
7
8

String URLString = new Scanner(System.in).next();

enter a URL

try {

9
10

java.net.URL url = new java.net.URL(URLString); create a URL object

int count = 0 ;

11
12

Scanner input = new Scanner(url.openStream());

create a Scanner object
more to read?
read a line

while (input.hasNext()) {

13
14 count += line.length();
15 }
16
17 System.out.println( "The file size is " + count + " bytes" );
18 }
19
20 System.out.println( "Invalid URL" );
21 }
22 catch (java.io.IOException ex) {
23 System.out.println( "I/O Errors: no such file" );
24 }
25 }
26 }

String line = input.nextLine();

catch (java.net.MalformedURLException ex) {

MalformedURLException

IOException

http://cs.armstrong.edu/liang/data/Lincoln.txt

Enter a URL:
The file size is 1469 bytes

Enter a URL:
The file size is 190006 bytes

http://www.yahoo.com

The program prompts the user to enter a URL string (line 6) and creates a URL object (line 9).
The constructor will throw a java.net.MalformedURLException (line 19) if the URL
isn't formed correctly.
The program creates a Scanner object from the input stream for the URL (line 11). If the
URL is formed correctly but does not exist, an IOException will be thrown (line 22). For
example, http://google.com/index1.html uses the appropriate form, but the URL itself does not
exist. An IOException would be thrown if this URL was used for this program.

MalformedURLException

14.37 How do you create a Scanner object for reading text from a URL?

✓ ✓

Check

Point

K EY T ERMS

absolute file name 541 exception 518

exception propagation chained exception 537 527

checked exception 525 relative file name 541

throw exception 526
unchecked exception

declare exception 526

directory path 541 525