HttpBodyServlet - response

Header Servlet

package hello.servlet.basic.response;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
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 = "responseHeaderServlet", urlPatterns = "/response-header")
public class ResponseHeaderSevlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException {
        //[status_line]
        //resp.setStatus(200); //숫자로 적어도 되지만 제공되는 상수 사용
        response.setStatus(HttpServletResponse.SC_OK); //성공시 반환 메시지 200


        //[response-header]
        response.setHeader("Content-Type", "text/plain;charset=utf-8");
        response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); //캐시를 저장하지 않는 코드
        response.setHeader("Prama", "no-cache"); // 캐시를 저장하지 않는 코드 과거 버전
        response.setHeader("my-header", "hello");

        //[header 편의 메소드]
        content(response);
        cookie(response);
        redirect(response);


        PrintWriter writer = response.getWriter();
        writer.println("clear");


    }
    private void content(HttpServletResponse response) {
        //Content-Type: text/plain;charset=utf-8
        //Content-Length: 2
        //response.setHeader("Content-Type", "text/plain;charset=utf-8");
        response.setContentType("text/plain");
        response.setCharacterEncoding("utf-8");
        // /response.setContentLength(2); //(생략시 자동 생성)
    }
    private void cookie(HttpServletResponse response) {
        //Set-Cookie: myCookie=good; Max-Age=600;
        //response.setHeader("Set-Cookie", "myCookie=good; Max-Age=600");
        Cookie cookie = new Cookie("myCookie", "good");
        cookie.setMaxAge(600); //600초
        response.addCookie(cookie);
    }

    private void redirect(HttpServletResponse response) throws IOException {
        //Status Code 302
        //Location: /basic/hello-form.html

        response.setStatus(HttpServletResponse.SC_FOUND); //302
        response.setHeader("Location", "/basic/hello-form.html");
        response.sendRedirect("/basic/hello-form.html");
    }
}

Json Servlet

package hello.servlet.basic.response;

import com.fasterxml.jackson.databind.ObjectMapper;
import hello.servlet.basic.HelloData;

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;

@WebServlet(name = "responseJsonServlet", urlPatterns = "/response-json")
public class ResponseJsonServlet extends HttpServlet {

    private ObjectMapper objectMapper = new ObjectMapper();

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //Content-Type : application/json
        resp.setContentType("application/json");
        resp.setCharacterEncoding("utf-8");

        HelloData helloData = new HelloData();
        helloData.setUsername("LEE");
        helloData.setAge(20);

        //{"username":"LEE", "age":20}
        String result = objectMapper.writeValueAsString(helloData);

        resp.getWriter().write(result);

        /**
         * spring mvc 사용시
         * HelloData helloData = new HelloData();
         * helloData.setUsername("LEE");
         * helloData.setAge(20);
         *
         * retunr helloData;
         */

    }
}

Html Servlet

package hello.servlet.basic.response;

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 = "responseHtmlServlet", urlPatterns = "/response-html")
public class ResponseHtmlServlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //Content-Type : text/html;charset=utf-8
        response.setContentType("text/html");
        response.setCharacterEncoding("utf-8");

        PrintWriter writer = response.getWriter();
        writer.println("<html>");
        writer.println("<body>");
        writer.println("    <div>안녕?</div>");
        writer.println("</body>");
        writer.println("</html>");
    }
}

결과값