[HTTP]HttpServletRequest 설명과 사용법

 

※ 이전 편 2025.02.27 - [☁ Network/🌏 HTTP] - [HTTP]HttpServlet 사용해보기 환경설정부터

 

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HttpServletRequest

 

• 서블릿은 개발자가 HTTP요청 메시지를 편리하게 사용할 수 있도록, 개발자 대신 HTTP 요청 메시지를 파싱한다.
  
  
• 그 결과를 HttepServletRequest 객체에 담아서 제공한다.
  
  
• 구성
  • START LINE
    - http method, URL,  쿼리 스트링, 스키마, 프로토콜
    
    
  • 헤더
    
    
  • 바디
    - form 파라미터 형식 조회
    
    
• 부가기능
  • 임시 저장소
    • 저장 : request.setAttribute(name, value)
      
      
    • 조회 : request.getAttribute(name)
  • 세션 관리 기능
    
    
    •  request.getSession(Create: true)

 

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기본 사용법

 

• code

  package hello.servlet.basic.request;
  
  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;
  
  @WebServlet(name = "requestHeaderServlet", urlPatterns = "/request-header")
  public class RequestHeaderServlet extends HttpServlet {
  
      @Override
      protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          printStartLine(request);
          printHeaders(request);
          printHeaderUtils(request);
          printEtc(request);
      }
  
      private void printStartLine(HttpServletRequest request) {
          System.out.println("--- REQUEST-LINE - start ---");
  
          System.out.println("request.getMethod() = " + request.getMethod()); //GET
          System.out.println("request.getProtocal() = " + request.getProtocol()); //HTTP/1.1
          System.out.println("request.getScheme() = " + request.getScheme()); //http
          // http://localhost:8080/request-header
          System.out.println("request.getRequestURL() = " + request.getRequestURL());
          // /request-test
          System.out.println("request.getRequestURI() = " + request.getRequestURI());
          //username=hi
          System.out.println("request.getQueryString() = " + request.getQueryString());
          System.out.println("request.isSecure() = " + request.isSecure()); //https 사용 유무
          System.out.println("--- REQUEST-LINE - end ---");
          System.out.println();
      }
  
      //Header 모든 정보
      private void printHeaders(HttpServletRequest request) {
          System.out.println("--- Headers - start ---");
  
  /*
          예전방식
          Enumeration<String> headerNames = request.getHeaderNames();
          while (headerNames.hasMoreElements()) {
              String headerName = headerNames.nextElement();
              System.out.println(headerName + ": " + headerName);
          }
  */
  
          request.getHeaderNames().asIterator()
                  .forEachRemaining(headerName -> System.out.println(headerName + ": " + headerName));
  
          System.out.println("--- Headers - end ---");
          System.out.println();
      }
  
      private void printHeaderUtils(HttpServletRequest request) {
          System.out.println("--- Header 편의 조회 start ---");
          System.out.println("[Host 편의 조회]");
          System.out.println("request.getServerName() = " + request.getServerName()); //Host 헤더
          System.out.println("request.getServerPort() = " + request.getServerPort()); //Host 헤더
          System.out.println();
  
          System.out.println("[Accept-Language 편의 조회]");
          request.getLocales().asIterator()
                  .forEachRemaining(locale -> System.out.println("locale = " + locale));
          System.out.println("request.getLocale() = " + request.getLocale());
          System.out.println();
  
          System.out.println("[cookie 편의 조회]");
          if (request.getCookies() != null) {
              for (Cookie cookie : request.getCookies()) {
                  System.out.println(cookie.getName() + ": " + cookie.getValue());
              }
          }
          System.out.println();
  
          System.out.println("[Content 편의 조회]");
          System.out.println("request.getContentType() = " + request.getContentType());
          System.out.println("request.getContentLength() = " + request.getContentLength());
          System.out.println("request.getCharacterEncoding() = " + request.getCharacterEncoding());
  
          System.out.println("--- Header 편의 조회 end ---");
          System.out.println();
      }
  
      //기타 정보
      private void printEtc(HttpServletRequest request) {
          System.out.println("--- 기타 조회 start ---");
  
          System.out.println("[Remote 정보]");
          System.out.println("request.getRemoteHost() = " + request.getRemoteHost()); //
          System.out.println("request.getRemoteAddr() = " + request.getRemoteAddr()); //
          System.out.println("request.getRemotePort() = " + request.getRemotePort()); //
          System.out.println();
  
          System.out.println("[Local 정보]");
          System.out.println("request.getLocalName() = " + request.getLocalName()); //
          System.out.println("request.getLocalAddr() = " + request.getLocalAddr()); //
          System.out.println("request.getLocalPort() = " + request.getLocalPort()); //
  
          System.out.println("--- 기타 조회 end ---");
          System.out.println();
      }
  }

• 인터넷 주소창에 http://localhost:8080/request-header 를 치고 들어간다.
  
  
• 출력결과

 

 

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※ 참조 : https://www.inflearn.com/roadmaps/373