HttpServletResponse - 기본 사용법

1. HttpServletReponse의 역할

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• 응답 메시지 생성
• 편의기능 제공

 

 

 

2. HTTP 응답 메시지 생성

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• HTTP 응답코드 지정
  • 200, 400, 500, 401..
• 헤더 생성
• 바디 생성

 

 

3. 편의기능

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• Content-Type, 쿠키, Redirect

 

 

 

4. 헤더 생성

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@WebServlet(name = "ResponseHeaderServlet", urlPatterns = "/response-header")
public class ResponseHeaderServlet extends HttpServlet {

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //[status-line] 응답코드
        response.setStatus(HttpServletResponse.SC_OK);

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

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

* 참고) 캐시 무효화 : https://bsh-developer.tistory.com/200?category=1039343

 

캐시 무효화하는 방법

 

 

5. Content 편의 메서드

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• Contentlength는 생략하면 자동 생성됨.

    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)
    }

 

 

 

6. 쿠키 편의 메서드

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2021.08.04 - [인프런/[인프런]모든 개발자를 위한 HTTP 웹 기본 지식] - Header - 쿠키

Header - 쿠키

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);
}

• 쿠키 객체 생성
• reponse.addCokie(쿠키) 사용 ㅋㅋ

 

 

 

 

7. redirect 편의 메서드

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• setHeader를 사용하는 경우
• /basic/hello-form.html 여기로 redirection해봄

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

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

오...

location 정보 대로 이동함 ㅋㅋ

• sendRedirect 사용하는 경우 ㅋㅋㅋㅋ 간단함

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

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

 

 

 

8. message Body

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//[Message Body]
PrintWriter writer = response.getWriter();
writer.println("ok");

 

 

9. GitHub : 210908 HttpServletResponse

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GitHub - bsh6463/MVC1