Dinesh on Java

Categories: Servlet

Servlets Auto Page Refresh

Consider a webpage which is displaying live game score or stock market status or currency exchange ration. For all such type of pages, you would need to refresh your web page regularly using referesh or reload button with your browser.

Java Servlet makes this job easy by providing you a mechanism where you can make a webpage in such a way that it would refresh automatically after a given interval.

The simplest way of refreshing a web page is using method setIntHeader() of response object. Following is the signature of this method:

public void setIntHeader(String header, int headerValue)

This method sends back header “Refresh” to the browser along with an integer value which indicates time interval in seconds.

Auto Page Refresh Example:

This example shows how a servlet performs auto page refresh using setIntHeader() method to set Refresh header.

Popular Tutorials

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class CounterServlet extends HttpServlet{
  public void doGet(HttpServletRequest request, 
  HttpServletResponse response)
  throws ServletException, IOException {
  HttpSession session = request.getSession(true);
  response.setIntHeader("Refresh", 5);
  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  Integer count = new Integer(0);
  String head;
  if (session.isNew()) {
  head = "This is the New Session";
  } else {
  head = "This is the old Session";
  Integer oldcount =(Integer)session.getValue("count"); 
  if (oldcount != null) {
  count = new Integer(oldcount.intValue() + 1);
  }
  }
  session.putValue("count", count);
  out.println("<HTML><BODY BGCOLOR="#FDF5E6">n" +
  "<H2 ALIGN="CENTER">" + head + "</H2>n" + 
  "<TABLE BORDER=1 ALIGN=CENTER>n"
  + "<TR BGCOLOR="#FFAD00">n" 
  +"  <TH>Information Type<TH>Session Countn" 
  +"<TR>n" +" <TD>Total Session Accessesn" +
  "<TD>" + count + "n" +
  "</TABLE>n" 
  +"</BODY></HTML>" );
  }
}

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Dinesh Rajput

Dinesh Rajput is the chief editor of a website Dineshonjava, a technical blog dedicated to the Spring and Java technologies. It has a series of articles related to Java technologies. Dinesh has been a Spring enthusiast since 2008 and is a Pivotal Certified Spring Professional, an author of a book Spring 5 Design Pattern, and a blogger. He has more than 10 years of experience with different aspects of Spring and Java design and development. His core expertise lies in the latest version of Spring Framework, Spring Boot, Spring Security, creating REST APIs, Microservice Architecture, Reactive Pattern, Spring AOP, Design Patterns, Struts, Hibernate, Web Services, Spring Batch, Cassandra, MongoDB, and Web Application Design and Architecture. He is currently working as a technology manager at a leading product and web development company. He worked as a developer and tech lead at the Bennett, Coleman & Co. Ltd and was the first developer in his previous company, Paytm. Dinesh is passionate about the latest Java technologies and loves to write technical blogs related to it. He is a very active member of the Java and Spring community on different forums. When it comes to the Spring Framework and Java, Dinesh tops the list!