15. HttpServletResponse - 기본 사용법

HttpServletResponse - 기본 사용법

 

HttpServletResponse 역할

 

HTTP 응답 메시지 생성

• HTTP 응답코드 지정
• 헤더 생성
• 바디 생성

 

편의 기능 제공

• Content-Type, 쿠키, Redirect

 

HttpServletResponse - 기본 사용법
hello.servlet.basic.response.ResponseHeaderServlet

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;
import java.net.http.HttpResponse;

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

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse
            response)
            throws ServletException, IOException {

        //[status-line]
        response.setStatus(HttpServletResponse.SC_OK); // HTTP 상태 코드 200으로 응답

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

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

        //[message body]
        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); //(생략시 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("myCookie", "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");
    }
}