Converting JavaScript function to Java

Question

I want to change this code from JavaScript to Java servlet. Can anyone guide me in finding the solution?

 var dob1 = document.getElementById(id).value;
 var today = new Date(),
 dob = new Date(dob1),
 age = new Date(today - dob).getFullYear() - 1970;

• Justin Garrick: Perhaps you mean Javascript? Retagging.
• Alois Cochard: Isn't JavaScript instead of HTML... or simply in which language is written the code you provide ? look a mix of JS/Java
• yopirates: no i wanted to use this function in java servlet.So i wanted the java servlet code for this
• t0mcat: with servlet, for first line of code you would need to do request.getParameter("name of field"); Servlets dont have the option to pick something with id. After that, SimpleDateFormat and Date class would get you going.
• Mikko Wilkman: The DOM access might be a bit tricky from as servlet, why don't you state the goal of the servlet instead? Is it to calculate age based on a http parameter or something else?

Answer 1

Use the Calendar API.

String dobString = "1978-03-26";
Date dobDate = new SimpleDateFormat("yyyy-MM-dd").parse(dobString);
Calendar dobCalendar = Calendar.getInstance();
dobCalendar.setTime(dobDate);
Calendar today = Calendar.getInstance();
int age = -1;
while (today.after(dobCalendar)) {
 age++;
 today.add(Calendar.YEAR, -1);
}
System.out.println(age); // 32

Since the Calendar API is horrible, I'd suggest JodaTime instead.

String dobString = "1978-03-26";
DateTime dobDate = DateTimeFormat.forPattern("yyyy-MM-dd").parseDateTime(dobString);
DateTime today = new DateTime();
int age = Years.yearsBetween(dobDate, today).getYears();
System.out.println(age); // 32

• yopirates: i m using datepicker and also date format for this.I have implemented this in jsp code and i want to implement the same code in servlet
• BalusC: OK. What stops you from doing this? (note that JSP != JavaScript)
• yopirates: yeah i know that. Let me give u my jsp code and servlet code.
• yopirates: function getAge(id) { getFormattedDate(id); var dob1 = document.getElementById(id).value; var today = new Date(), dob = new Date(dob1), age = new Date(today - dob).getFullYear() - 1970; document.getElementById('age').value = age; }
• t0mcat: Here is an Ant file which converts JSP code to Servlet (I havent tried on my own). You should go through some jsp/servlet tutorials. arulraj.net/2010/04/jsp-to-servlet-converter.html