Hi. I want help to connect my web application to my MYSQL database and to extract only specific column to return its values to my application Also I want to know is there any specific filter in java that will allow a crawler to crawl only a collection of URLs from any seed web site.
Is there any ARC to xml Converter? Please give me a reference if it exists.

For you first question, read the tuttorial in the JSP section, by peter_budo. Extracting only the information of some specific column depends on the query you write.

For your second question, search this forum as there have been several queries about crawlers in java. They have been given enough help/pointers.

For your third question, search google.