Validating fields in html
A typical scenario is the user fills in fields of a form and submits it. Note that we use the - in the servlet set the value you want to transfer to the JSP page using the set Attribute() method on the request object.- in the JSP page, use the get Attribute() method on the request object to retrieve the value.The server will process the request based on the submitted data, and send response back to the client. Servlet Exception; import javax.servlet.annotation. To transfer control from a servlet to a JSP page, use the Request Dispatcher() method.If the input field comes from a fixed set of options, like a drop down list or radio buttons, then the input needs to match exactly one of the values offered to the user in the first place.Free-form text, especially with Unicode characters, is perceived as difficult to validate due to a relatively large space of characters that need to be whitelisted.Please note, email addresses should be considered to be public data.Many web applications contain computationally expensive and inaccurate regular expressions that attempt to validate email addresses.
private static final Pattern zip Pattern = Pattern.compile("^\d(-\d)?
Input validation can be implemented using any programming technique that allows effective enforcement of syntactic and semantic correctness, for example: , where the ' character is fully legitimate.
For more information on XSS filter evasion please see the XSS Filter Evasion Cheat Sheet.
Input validation should be applied on both syntactical and semantic level.
Syntactic validation should enforce correct syntax of structured fields (e.g.