Java Reference
In-Depth Information
Example 7-4
reads URLs from the command line and uses these six methods to print
their content type, content length, content encoding, date of last modification, expira‐
tion date, and current date.
Example 7-4. Return the header
import
java.io.*
;
import
java.net.*
;
import
java.util.*
;
public
class
HeaderViewer
{
public
static
void
main
(
String
[]
args
)
{
for
(
int
i
=
0
;
i
<
args
.
length
;
i
++)
{
try
{
URL
u
=
new
URL
(
args
[
0
]);
URLConnection
uc
=
u
.
openConnection
();
System
.
out
.
println
(
"Content-type: "
+
uc
.
getContentType
());
if
(
uc
.
getContentEncoding
()
!=
null
)
{
System
.
out
.
println
(
"Content-encoding: "
+
uc
.
getContentEncoding
());
}
if
(
uc
.
getDate
()
!=
0
)
{
System
.
out
.
println
(
"Date: "
+
new
Date
(
uc
.
getDate
()));
}
if
(
uc
.
getLastModified
()
!=
0
)
{
System
.
out
.
println
(
"Last modified: "
+
new
Date
(
uc
.
getLastModified
()));
}
if
(
uc
.
getExpiration
()
!=
0
)
{
System
.
out
.
println
(
"Expiration date: "
+
new
Date
(
uc
.
getExpiration
()));
}
if
(
uc
.
getContentLength
()
!=
-
1
)
{
System
.
out
.
println
(
"Content-length: "
+
uc
.
getContentLength
());
}
}
catch
(
MalformedURLException
ex
)
{
System
.
err
.
println
(
args
[
i
]
+
" is not a URL I understand"
);
}
catch
(
IOException
ex
)
{
System
.
err
.
println
(
ex
);
}
System
.
out
.
println
();
}
}
}
Here's the result when used to look at
http://www.oreilly.com
:
%
java HeaderViewer http://www.oreilly.com
Content-type: text/html; charset=utf-8
Date: Fri May 31 18:08:09 EDT 2013
Last modified: Fri May 31 17:04:14 EDT 2013
