The difference between SendRedirect and forward is one of the classical interview questions asked during a java web developer interview. This is not just applicable for servlet but also for JSP in which we can use forward action or call sendRedirect() method from scriptlet. Before examining the difference between forward and SendRedirect let’s see what send Redirect method and the forward method does.
SendRedirect ():
This method is declared in HttpServletResponse Interface.
Signature: void sendRedirect(String url)
This method is used to redirect the client requests to some other location for further processing, the new location is available on different servers or different contexts. Our web container handles this and transfers the request using a browser, and this request is visible in the browser as a new request. Sometimes this is also called a client-side redirect.
Forward():
This method is declared in RequestDispatcher Interface.
Signature: forward(ServletRequest request, ServletResponse response)
This method is used to pass the request to another resource for further processing within the same server, another resource could be any servlet, jsp page any kind of file.
This process is taken care of by a web container when we call forward method request is sent to another resource without the client being informed, which resource will handle the request it has been mention on requestDispatcher object which we can get in two ways either using ServletContext or Request. This is also called a server-side redirect.
RequestDispatcher rd = request.getRequestDispatcher("pathToResource");
rd.forward(request, response);Or
RequestDispatcher rd = servletContext.getRequestDispatcher("/pathToResource");
rd.forward(request, response);Difference between SendRedirect and Forward
Now let’s see some differences between these two methods of servlet API in tabular format.
Forward() | SendRediret() |
When we use the forward method request is transferred to other resources within the same server for further processing. | In case of sendRedirect request is transferred to another resource to a different domain or different server for further processing. |
In case of forward Web container handle all process internally and client or browser is not involved. | When you use the SendRedirect container transfers the request to the client or browser so url given inside the sendRedirect method is visible as a new request to the client. |
When forward is called on requestdispather object we pass request and response object so our old request object is present on new resource which is going to process our request | In case of SendRedirect call old request and response object is lost because it’s treated as new request by the browser. |
Visually we are not able to see the forwarded address, its is transparent | In the address bar we are able to see the new redirected address it’s not transparent. |
Using the forward () method is faster than send a redirect. | SendRedirect is slower because one extra round trip is required because a completely new request is created and the old request object is lost. Two browser requests required. |
When we redirect using forward and we want to use the same data in a new resource we can use the request.setAttribute () as we have request object available. | But in sendRedirect if we want to use we have to store the data in session or pass along with the URL. |
Example of forwarding and SendRedirect in JSP Servlet:
Any kind of online payment when we use the merchant site will redirect us to the net banking site which is a completely new request it processes our request and again redirect to the merchant site?
In Banking Application when we do login normally we use the forward method. In the case of online banking, we are asked for a username and password if it’s correct some other servlet or resource will handle the request otherwise request has been forwarded to an error page.
Which one is good?
It depends upon the scenario that which method is more useful.
If you want control is transfer to a new server or context and it is treated as a completely new task then we go for Send Redirect.
Normally forward should be used if the operation can be safely repeated upon a browser reload of the web page will not affect the result.
SendRedirect and forward methods are still very useful while programming or working on any web application project using servlet jsp. This is still a popular interview question so don’t forget to revise forward and sendRedirect before appearing for any job interview.
