▪️ex62servlet.java

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/ex62servlet")
public class ex62servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        int r = new java.util.Random().nextInt(10);
        if (r % 2 == 0) {
            RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/forwarded.jsp");
            dispatcher.forward(request, response);
        } else {
            response.sendRedirect("/ex62/redirected.jsp");

        }

    }
}

▪️forwarded.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset=UTF-8">
<title>フォワード</title>
</head>
<body>
    <h1>フォワードされたページ</h1>
</body>
</html>

▪️redirected.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset=UTF-8">
<title>リダイレクト</title>
</head>
<body>
    <h1>リダイレクトされたページ</h1>
</body>
</html>