Vlad class work #12

Application.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.servlet.http.HttpServletRequest;

@EnableAutoConfiguration
@Controller
public class Application {
    String s="";
    
    @RequestMapping("")
    @ResponseBody
    public String first(HttpServletRequest request) {
        if("true".equals(request.getParameter("clean"))) {
            s = "";
        }

        String message = request.getParameter("message");

        if(message !=null) {
            s += message + "<br>";
        }

        return s + "Please enter some value" +
                "<form method=post action=/>" +
                "<input name=message>" +
                "<input type=submit value=Send>" +
                "</form>" +
                "<br>" +
                "<a href='?clean=true'>Clean</a>";
    }
    
    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }
}