Java Reference
In-Depth Information
URL
u
=
new
URL
(
"http://mesola.obspm.fr/"
);
Object
o
=
u
.
getContent
();
// cast the Object to the appropriate type
// work with the Object...
getContent()
operates by looking at the
Content-type
field in the header of the data
it gets from the server. If the server does not use MIME headers or sends an unfamiliar
Content-type
,
getContent()
returns some sort of
InputStream
with which the data
can be read. An
IOException
is thrown if the object can't be retrieved.
Example 5-3
demonstrates this.
Example 5-3. Download an object
import
java.io.*
;
import
java.net.*
;
public
class
ContentGetter
{
public
static
void
main
(
String
[]
args
)
{
if
(
args
.
length
>
0
)
{
// Open the URL for reading
try
{
URL
u
=
new
URL
(
args
[
0
]);
Object
o
=
u
.
getContent
();
System
.
out
.
println
(
"I got a "
+
o
.
getClass
().
getName
());
}
catch
(
MalformedURLException
ex
)
{
System
.
err
.
println
(
args
[
0
]
+
" is not a parseable URL"
);
}
catch
(
IOException
ex
)
{
System
.
err
.
println
(
ex
);
}
}
}
}
Here's the result of trying to get the content of
http://www.oreilly.com
:
%
java
ContentGetter
http:
//www.oreilly.com/ I got a
sun
.
net
.
www
.
protocol
.
http
.
HttpURLConnection
$HttpInputStream
</
programlisting
>
The exact class may vary from one version of Java to the next (in earlier versions, it's
been
java.io.PushbackInputStream
or
sun.net.www.http.KeepAliveStream
) but it
should be some form of
InputStream
.
Here's what you get when you try to load a header image from that page:
%
java
ContentGetter
http:
//www.oreilly.com/graphics_new/animation.gif
I
got
a
sun
.
awt
.
image
.
URLImageSource
</
programlisting
>
Here's what happens when you try to load a Java applet using
getContent()
:
