How to solve "java.lang.IllegalStateException: Cannot forward after response has been committed" error




1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
package simple;
 
import java.io.IOException;
import java.util.Date;
 
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class SimpleController extends HttpServlet {
 
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        super.doGet(request, response);
        processRequest(request, response);
    }
 
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        super.doPost(request, response);
        processRequest(request, response);
    }
 
    private void processRequest(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{
        String type = request.getParameter("type");
        Object resultObject = null;
        if(type == null || type.equals("greeting")) {
            resultObject = "안녕하세요 ";
        } else if(type.equals("date")) {
            resultObject = new Date();
        } else {
            resultObject = "Invalid Type";
        }
        
        request.setAttribute("result", resultObject);
        
        RequestDispatcher dispatcher = request.getRequestDispatcher("/chap18/simpleView.jsp");
        dispatcher.forward(request, response);
    }
}
cs


When I run above controller, I met "java.lang.IllegalStateException: Cannot forward after response has been committed" error.

This is because The super.doGet(request, response); and super.doPost(request, response); calls.

I solve this error by erasing super.doGet(request, response); and super.doPost(request, response);