问一个servlet 请求转发有关问题

问一个servlet 请求转发问题

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class Test extends HttpServlet {

	
	public void  doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	   
		//System.out.println("a");
		//return null;
		test(request,response);
	}

	public String test(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
	    response.setContentType("text/html; charset=gb2312"); 
		ServletContext sc = getServletContext(); 
		RequestDispatcher rd = null; 
		rd=sc.getRequestDispatcher("/index.jsp");
		rd.forward(request,response);
		return null;
	}
	
}

抛异常了

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
at Test.test(Test.java:27)
at Test.doGet(Test.java:19)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
------解决方案--------------------
RequestDispatcher rd = request.getRequestDispatcher("/index.jsp"); 
rd.forward(request, response);
试试