老是报此URL不支持Http方法GET和请求行中接收的方法由源服务器知道，但目标资源不支持。不是很理解 ，能帮忙解读一下吗

package com.demo;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
@WebServlet(name = "examServlet" ,urlPatterns="/ExamServlet")
public class ExamServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response . setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        String quest1 = request.getParameter("q1");
        String quest2 = request.getParameter("q2").trim();
        String[] quest3 = request.getParameterValues("q3");
        String quest4 = request.getParameter("q4");
        int score =0;

        if(quest1!=null && quest1.equals("3")){
            score = score+25;
        }
        if(quest2!=null && (quest2.equals("HttpServlet"))){
            score =score+25;
        }
        if (quest3!=null && quest3.length==2 && quest3[0].equals("1") && quest3[1].equals("3")){
            score=score+25;
        }
        if (quest4!=null && quest4.equals("3")){
            score=score+25;
        }
        out.println("你的成绩是："+score+"分");
    }
}