[스프링 MVC] HttpServletResponse 기본 사용법

HttpServletResponse 역할

 

HTTP 응답 메세지 생성

- HTTP 응답코드 지정

- 헤더 생성

- 바디 생성

 

편의 기능 제공

Content-Type, 쿠키, Redirect

 

hello.servlet.basic.response.ResponseHeaderServlet

package hello.servlet.basic.response;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;

@WebServlet(name="responseHeaderServlet", urlPatterns="/response-header")
public class ResponseHeaderServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // [status-line]
        response.setStatus(HttpServletResponse.SC_OK);

        // [response-headers]
        response.setHeader("Content-Type", "text/plain;charset=utf-8");
        response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
        response.setHeader("Pragma", "no-cache");
        response.setHeader("my-header", "hello");

        // [Header의 편의 메서드]
        // content(response);
        // cookie(response);
        redirect(response);

        PrintWriter writer = response.getWriter();
        writer.println("ok");
    }

 

Content 편의 메서드

 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); // 생략 시 자동 생성
    }

 

쿠키 편의 메서드

    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("my-cookie", "good");
        cookie.setMaxAge(600); // 600초
        response.addCookie(cookie);
    }

 

redirect 편의 메서드

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");
    }