What is the difference between forward and sendredirect?

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Both method calls redirect you to new resource/page/servlet. The difference between the two is that sendRedirect always sends a header back to the client/browser, containing the data in which you wanted to be redirected.

In Java, particularly in the context of servlets and JSP (JavaServer Pages), forward and sendRedirect are two different mechanisms used for controlling the flow of a request from one component to another. Here are the main differences between them:

  1. Server-Side vs Client-Side Redirect:
    • Forward: It is a server-side redirect. The request is internally forwarded to another resource (like another servlet or JSP) on the server, and the client is not involved in the redirection process.
    • sendRedirect: It is a client-side redirect. The server sends a response to the client with a special HTTP status code, and the client’s browser then makes a new request to the specified URL.
  2. Request and Response Objects:
    • Forward: It is done using the RequestDispatcher interface. The original request and response objects are reused in the forwarded resource.
    • sendRedirect: It involves a new request and response. The original request and response objects are not reused.
  3. URL Changes:
    • Forward: The URL remains the same. The client is unaware of the resource to which the request is forwarded on the server side.
    • sendRedirect: The URL changes in the client’s browser. The client is aware of the new URL to which the request is redirected.
  4. Performance:
    • Forward: Generally more efficient as it is handled internally on the server.
    • sendRedirect: Might have a slight performance overhead because it involves an additional round-trip between the client and the server.
  5. Usage:
    • Forward: Typically used when multiple servlets or components need to collaborate to generate a response.
    • sendRedirect: Used when you want the client to initiate a new request to a different resource, especially on a different server or context.

Here is a basic example of how they are used:

java
// Using Forward
RequestDispatcher dispatcher = request.getRequestDispatcher("newResource.jsp");
dispatcher.forward(request, response);// Using sendRedirect
response.sendRedirect(“newResource.jsp”);

In summary, the choice between forward and sendRedirect depends on the specific requirements of your application and the desired behavior for handling the request.