String, text, numbers, I/O II part

but it didn t seem to work

Answer:

URL url = new URL("http://www.java.sun.com");

BufferedReader in;

in = new BufferedReader(new InputStreamReader(url.openStream()));

String str;

while ((str = in.readLine())!=null){

   // process str

}

you can use this to retrieve a html file.

Cheng Tao

 Q: I am wondering if JDK supports to open a file in the exclusive mode?

Answer: No, file locking is not supported in current VMs. You can implement

lockfiles, however, using the File.createNewFile() method. Since JDK 1.3: 

"Atomically creates a new, empty file named by this abstract pathname if and only if

a file with this name does not yet exist. The check for the   existence of the file and

the creation of the file if it does not exist are a single operation that is atomic with

respect to all other filesystem activities that might affect the file. This method, in

combination with the deleteOnExit() method, can therefore serve as the basis for a

simple but reliable cooperative file locking protocol."

 Q: How do I write an image to stdout? This is for a cgi program that will return an

image to a browser.

For example, if a user click on a link to 

http://somewhere.edu/cgi/getpix.cgi

 the

browser will receive image data from the cgi program and will display the image.

Answer: Send "Content type: image/gif"   and then send the data.

Alternatively, send an HTML page, with a pointer to the (possibly freshly written)

image on the server.

Tim Tyler Try my latest game   it rockz   http://rockz.co.uk/

 Q: Does anyone know how I can get around the fact that a Message obj (from

the JavaMail API) is not serializable?

I would like to save a message obj to the hd, then read the file (is  file  the wrong

word here?) back to my e mail client and read it as a Message obj.

Answer: The obvious answer is: implement serializable yourself in a subclass!

But! That won t work. The serialization mechanism will throw an exception at runtime.

Even if it didn t, the class may be nonserializable for a good reason, for example it

might contain a socket, which can t be reinitialized from a stream.

What you need is a subclass that implements the Externalizable interface, and then

your own code that saves as serializable objects those attributes of the object that

you need to reconstitute it later. I m not familiar with this particular object, but I

imagine it has several get() methods that return serializable objects like Strings or

ints. What you have to do is recover those objects and put them into the output

stream yourself, and reverse the process on unserialization. The fields that are not

file:///F|/a_jsite/350_tips/stings_text__date_numbers_io II.htm (4 of 7) [2001 07 08 11:25:00]