[Spring] HttpServletRequest의 기본 기능 header, start-line 정보 조회하기

HttpServletRequest의 기본 기능

HttpServletRequest가 제공하는 기본 기능들을 알아보자.

 

start-line 정보
헤더 정보
Header 편리한 조회
기타 정보를 출력해볼 것이다. 

 

header, start-line 정보 조회하기

package hello.servlet.basic.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
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);
       response.getWriter().write("ok");
    }
    private void printStartLine(HttpServletRequest request) {
        System.out.println("--- REQUEST-LINE - start ---");
        System.out.println("request.getMethod() = " + request.getMethod()); //GET
        System.out.println("request.getProtocol() = " + 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-header
        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 ---");
        /*
         Enumeration<String> headerNames = request.getHeaderNames();
         while (headerNames.hasMoreElements()) {
         String headerName = headerNames.nextElement();
         System.out.println(headerName + ": " + request.getHeader(headerName));
         }
        */
        request.getHeaderNames().asIterator().forEachRemaining(headerName -> System.out.println(headerName + ": " + request.getHeader(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();
    }
}

 

출력 결과 

오후 10:11:42: Executing ':ServletApplication.main()'...

Starting Gradle Daemon...
Gradle Daemon started in 4 s 318 ms
> Task :compileJava UP-TO-DATE
> Task :processResources
> Task :classes

> Task :ServletApplication.main()

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::               (v2.7.13)

2023-07-12 22:11:58.460  INFO 7076 --- [           main] hello.servlet.ServletApplication         : Starting ServletApplication using Java 11 on DESKTOP-826J7UH with PID 7076 (C:\Users\tmdgh\study\servlet\build\classes\java\main started by tmdgh in C:\Users\tmdgh\study\servlet)
2023-07-12 22:11:58.465  INFO 7076 --- [           main] hello.servlet.ServletApplication         : No active profile set, falling back to 1 default profile: "default"
2023-07-12 22:12:01.046  INFO 7076 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-07-12 22:12:01.066  INFO 7076 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-07-12 22:12:01.066  INFO 7076 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.76]
2023-07-12 22:12:01.245  INFO 7076 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-07-12 22:12:01.245  INFO 7076 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2686 ms
2023-07-12 22:12:01.720  INFO 7076 --- [           main] o.s.b.a.w.s.WelcomePageHandlerMapping    : Adding welcome page: ServletContext resource [/index.html]
2023-07-12 22:12:01.992  INFO 7076 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-07-12 22:12:02.007  INFO 7076 --- [           main] hello.servlet.ServletApplication         : Started ServletApplication in 4.284 seconds (JVM running for 5.054)
2023-07-12 22:12:09.559 DEBUG 7076 --- [nio-8080-exec-1] o.a.coyote.http11.Http11InputBuffer      : Before fill(): parsingHeader: [true], parsingRequestLine: [true], parsingRequestLinePhase: [0], parsingRequestLineStart: [0], byteBuffer.position(): [0], byteBuffer.limit(): [0], end: [0]
2023-07-12 22:12:09.559 DEBUG 7076 --- [nio-8080-exec-1] o.a.coyote.http11.Http11InputBuffer      : Received [GET //request-header HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Cache-Control: max-age=0
sec-ch-ua: "Not.A/Brand";v="8", "Chromium";v="114", "Google Chrome";v="114"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: none
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Accept-Encoding: gzip, deflate, br
Accept-Language: ko-KR,ko;q=0.9,en-US;q=0.8,en;q=0.7

]
--- REQUEST-LINE - start ---
request.getMethod() = GET
request.getProtocol() = HTTP/1.1
request.getScheme() = http
request.getRequestURL() = http://localhost:8080//request-header
request.getRequestURI() = //request-header
request.getQueryString() = null
request.isSecure() = false
--- REQUEST-LINE - end ---

--- Headers - start ---
host: localhost:8080
connection: keep-alive
cache-control: max-age=0
sec-ch-ua: "Not.A/Brand";v="8", "Chromium";v="114", "Google Chrome";v="114"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
upgrade-insecure-requests: 1
user-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36
accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
sec-fetch-site: none
sec-fetch-mode: navigate
sec-fetch-user: ?1
sec-fetch-dest: document
accept-encoding: gzip, deflate, br
accept-language: ko-KR,ko;q=0.9,en-US;q=0.8,en;q=0.7
--- Headers - end ---

--- Header 편의 조회 start ---
[Host 편의 조회]
request.getServerName() = localhost
request.getServerPort() = 8080

[Accept-Language 편의 조회]
locale = ko_KR
locale = ko
locale = en_US
locale = en
request.getLocale() = ko_KR

[cookie 편의 조회]

[Content 편의 조회]
request.getContentType() = null
request.getContentLength() = -1
request.getCharacterEncoding() = UTF-8
--- Header 편의 조회 end ---

--- 기타 조회 start ---
[Remote 정보]
request.getRemoteHost() = 0:0:0:0:0:0:0:1
request.getRemoteAddr() = 0:0:0:0:0:0:0:1
request.getRemotePort() = 58711

[Local 정보]
request.getLocalName() = 0:0:0:0:0:0:0:1
request.getLocalAddr() = 0:0:0:0:0:0:0:1
request.getLocalPort() = 8080
--- 기타 조회 end ---

2023-07-12 22:12:09.625 DEBUG 7076 --- [nio-8080-exec-1] o.a.coyote.http11.Http11InputBuffer      : Before fill(): parsingHeader: [true], parsingRequestLine: [true], parsingRequestLinePhase: [0], parsingRequestLineStart: [0], byteBuffer.position(): [0], byteBuffer.limit(): [0], end: [719]
2023-07-12 22:12:09.625 DEBUG 7076 --- [nio-8080-exec-1] o.a.coyote.http11.Http11InputBuffer      : Received []
2023-07-12 22:12:09.625 DEBUG 7076 --- [nio-8080-exec-1] o.apache.coyote.http11.Http11Processor   : Socket: [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@78628c93:org.apache.tomcat.util.net.NioChannel@38353d4b:java.nio.channels.SocketChannel[connected local=0:0:0:0:0:0:0:1/0:0:0:0:0:0:0:1:8080 remote=/0:0:0:0:0:0:0:1:58711]], Status in: [OPEN_READ], State out: [OPEN]

 

 

---

지금까지 HttpServletRequest를 통해서 HTTP 메시지의 start-line, header 정보 조회 방법을 알아봤다. f12를 누른다음 네트워크에서도 헤더 정보를 확인할 수 있다.

 

HttpServletRequest를 사용하는 이유는 다음과 같다. 

1. HTTP 요청을 처리하기 위해 클라이언트에서 서버로 전송된 데이터를 읽을 수 있다.
2. start-line과 header 정보를 분석하여 요청의 성격과 목적을 이해할 수 있다.
3. 매개변수, 쿠키, 세션 등의 데이터에 접근할 수 있다.
4. 클라이언트의 정보(브라우저, IP 주소 등)를 확인할 수 있다.