JSP Method for Repeated Submission of Forms

In this paper, an example is given to describe the processing method of JSP for repeated submission of forms. Share it for your reference, as follows:

1. Perform the following when generating the form:

session.setAttribute("forum_add", "forum_add");

2. Make the following judgment when submitting for processing

if (isRedo(request, "forum_add")) {
 // Prompt for repeated submission , Make relevant treatment 
}

Correlation function:

/**
*  Determine whether it is a duplicate submission 
* 1 , check Session Contains an attribute with the specified name in 
* 2 , if Session If there is no attribute in or the attribute is empty, it proves that it has been processed and it is judged as repeated submission 
* 3 Otherwise, the proof is the first 1 Is processed, and the property is changed from the Session Delete from. 
* @param key String
*/
private boolean isRedo(HttpServletRequest request, String key) {
  String value = (String) request.getSession().getAttribute(key);
  if (value == null) {
   return true;
  }
  else {
   request.getSession().removeAttribute(key);
   return false;
  }
}

I hope this article is helpful to everyone's JSP programming.