如何在servlet中创建URL？

import java.io.IOException;
import java.io.PrintWriter;
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("/CreateURL")
public class CreateURLServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 设置响应内容类型
        response.setContentType("text/html");

        // 获取PrintWriter对象以写入响应内容
        PrintWriter out = response.getWriter();

        // 使用HttpServletRequest对象的内置方法创建URL
        String url = request.getRequestURL().toString();

        // 将URL写入响应内容
        out.println("<h1>创建的URL是: " + url + "</h1>");
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}