part2(2013/11/27)

Called by the server (via the service method) to allow a servlet to handle a OPTIONS request. The OPTIONS request determines which HTTP methods the server supports and returns an appropriate header. For example, if a servlet overrides doGet, this method returns the following header:

Allow: GET, HEAD, TRACE, OPTIONS

There's no need to override this method unless the servlet implements new HTTP methods, beyond those implemented by HTTP 1.1.

Parameters:

req the HttpServletRequest object that contains the request the client made of the servlet

resp the HttpServletResponse object that contains the response the servlet returns to the client

Throws:

java.io.IOException if an input or output error occurs while the servlet is handling the OPTIONS request

javax.servlet.ServletException if the request for the OPTIONS cannot be handled

522

523

    protected void doOptions(HttpServletRequest req, HttpServletResponse resp)

524

        throws ServletException, IOException

525

    {

//아까 분석한 대로 내가 재정의한 HttpServlet 파생 클래스부터 HttpServelt 이전 까지 정의도니 내가

//"재정의한" 메서드들 리턴.

526

        Method[] methods = getAllDeclaredMethods(this.getClass());

527

528

        boolean ALLOW_GET = false;

529

        boolean ALLOW_HEAD = false;

530

        boolean ALLOW_POST = false;

531

        boolean ALLOW_PUT = false;

532

        boolean ALLOW_DELETE = false;

533

        boolean ALLOW_TRACE = true;

534

        boolean ALLOW_OPTIONS = true;

535

536

        for (int i=0; i<methods.length; i++) {

537

            String methodName = methods[i].getName();

538

     //너무 직관적인 코드니 생략. get은 <a> <img>였나? 이미지나 문자 보낼때 자동으로

     //get메서드 실행되고, 그외엔 보안등 강점을 이유로 대부분 post로 사용한다고

    //했었던 기억이 뇌리를 스침..

539

            if (methodName.equals("doGet")) {

540

                ALLOW_GET = true;

541

                ALLOW_HEAD = true;

542

            } else if (methodName.equals("doPost")) {

543

                ALLOW_POST = true;

544

            } else if (methodName.equals("doPut")) {

545

                ALLOW_PUT = true;

546

            } else if (methodName.equals("doDelete")) {

547

                ALLOW_DELETE = true;

548

            }

549

550

        }

551

552

        // we know "allow" is not null as ALLOW_OPTIONS = true

553

        // when this method is invoked

//오 위에서 직관적이라 표현한 부분이 아래의 처리를 위해서 그런거였구나..

//내가 재정의한 메서드를 통해 나만의 스타일로 스크립트 문자열을 만들어주고 있는듯?

554

        StringBuilder allow = new StringBuilder();

555

        if (ALLOW_GET) {

556

            allow.append(METHOD_GET);

557

        }

558

        if (ALLOW_HEAD) {

559

            if (allow.length() > 0) {

560

                allow.append(", ");

561

            }

562

            allow.append(METHOD_HEAD);

563

        }

564

        if (ALLOW_POST) {

565

            if (allow.length() > 0) {

566

                allow.append(", ");

567

            }

568

            allow.append(METHOD_POST);

569

        }

570

        if (ALLOW_PUT) {

571

            if (allow.length() > 0) {

572

                allow.append(", ");

573

            }

574

            allow.append(METHOD_PUT);

575

        }

576

        if (ALLOW_DELETE) {

577

            if (allow.length() > 0) {

578

                allow.append(", ");

579

            }

580

            allow.append(METHOD_DELETE);

581

        }

582

        if (ALLOW_TRACE) {

583

            if (allow.length() > 0) {

584

                allow.append(", ");

585

            }

586

            allow.append(METHOD_TRACE);

587

        }

588

        if (ALLOW_OPTIONS) {

589

            if (allow.length() > 0) {

590

                allow.append(", ");

591

            }

592

            allow.append(METHOD_OPTIONS);

593

        }

594

595

        resp.setHeader("Allow", allow.toString());

596

    }
    
    
    

Called by the server (via the service method) to allow a servlet to handle a TRACE request. A TRACE returns the headers sent with the TRACE request to the client, so that they can be used in debugging. There's no need to override this method.

Parameters:

req the HttpServletRequest object that contains the request the client made of the servlet

resp the HttpServletResponse object that contains the response the servlet returns to the client

Throws:

java.io.IOException if an input or output error occurs while the servlet is handling the TRACE request

javax.servlet.ServletException if the request for the TRACE cannot be handled

622

623

    protected void doTrace(HttpServletRequest req, HttpServletResponse resp) 

624

        throws ServletException, IOException

625

    {

626

627

        int responseLength;

628

//캐리지 리턴과 라인 넥스트의 조합? 한칸 내리고 제일 앞으로 땡기고? 타이핑?

// == 엔터키를 쳣을때 입력되는 값을 의미한다. (엔터치면 \r\n 이 들어옴)

629

        String CRLF = "\r\n";

// TRACE 도 스크립트 언어인듯함? 유저의 url주소 적어주고, 유저가 보낸 프로토콜(일반적으론 http)

//적어주고

630

        StringBuilder buffer = new StringBuilder("TRACE ").append(req.getRequestURI())

631

            .append(" ").append(req.getProtocol());

632

//대충 .jsp파일 만들었을때 제일 앞에 위치하던.. 이 정보를 만드는 과정 아닐까? 싶은데..

//아직 기본개념및 이해가 부족하다...

/*

<%@ page language="java" contentType="text/html; charset=EUC-KR"

    pageEncoding="EUC-KR"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

*/

633

        Enumeration<String> reqHeaderEnum = req.getHeaderNames();

634

635

        while( reqHeaderEnum.hasMoreElements() ) {

636

            String headerName = reqHeaderEnum.nextElement();

637

            buffer.append(CRLF).append(headerName).append(": ")

638

                .append(req.getHeader(headerName));

639

        }

640

641

        buffer.append(CRLF);

642

643

        responseLength = buffer.length();

644

645

        resp.setContentType("message/http");

646

        resp.setContentLength(responseLength);

647

        ServletOutputStream out = resp.getOutputStream();

648

        out.print(buffer.toString());

649

    }


    

Receives standard HTTP requests from the public service method and dispatches them to the doXXX methods defined in this class. This method is an HTTP-specific version of thejavax.servlet.Servlet.service(javax.servlet.ServletRequest,javax.servlet.ServletResponse) method. There's no need to override this method.

Parameters:

req the HttpServletRequest object that contains the request the client made of the servlet

resp the HttpServletResponse object that contains the response the servlet returns to the client

Throws:

java.io.IOException if an input or output error occurs while the servlet is handling the HTTP request

javax.servlet.ServletException if the HTTP request cannot be handled

See also:

javax.servlet.Servlet.service(javax.servlet.ServletRequest,javax.servlet.ServletResponse)

676

677

    protected void service(HttpServletRequest req, HttpServletResponse resp)

678

        throws ServletException, IOException

679

    {

//유저가 보낸 요청 메서드는 무엇이냐? get?post?

680

        String method = req.getMethod();

681

682

        if (method.equals(METHOD_GET)) {

//getLastModified가 뭐였지? part1에 있던건가.. part1에서 잘라왔음.

/*

<div class="line" id="line-245" style="font-family: 'Lucida Grande', Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: -2px 0px 0px; padding: 0px 0px 0px 10px; color: rgb(68, 29, 42); white-space: normal;"><div class="lnml" id="lnml-245" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><div class="ln" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px 6px; display: inline;">
245
</div><div class="lnmr" id="lnmr-245" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><pre style="margin-top: 0px; margin-bottom: 0px; display: inline;">    protected long getLastModified(HttpServletRequest req) {</pre></div><div class="line" id="line-246" style="font-family: 'Lucida Grande', Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: -2px 0px 0px; padding: 0px 0px 0px 10px; color: rgb(68, 29, 42); white-space: normal;"><div class="lnml" id="lnml-246" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><div class="ln" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px 6px; display: inline;">
246
</div><div class="lnmr" id="lnmr-246" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><pre style="margin-top: 0px; margin-bottom: 0px; display: inline;">        return -1;</pre></div><div class="line" id="line-247" style="font-family: 'Lucida Grande', Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: -2px 0px 0px; padding: 0px 0px 0px 10px; color: rgb(68, 29, 42); white-space: normal;"><div class="lnml" id="lnml-247" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><div class="ln" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px 6px; display: inline;">
247
</div><div class="lnmr" id="lnmr-247" style="font-family: 돋움, dotum, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: 0px; padding: 0px; display: inline;"></div><pre style="margin-top: 0px; margin-bottom: 0px; display: inline;">    }
</pre></div><div class="line" id="line-247" style="font-family: 'Lucida Grande', Tahoma, Verdana, Arial, Helvetica, sans-serif; font-size: 12px; list-style: none; margin: -2px 0px 0px; padding: 0px 0px 0px 10px; color: rgb(68, 29, 42); white-space: normal;"><pre style="margin-top: 0px; margin-bottom: 0px; display: inline;">*/</pre></div>

683

            long lastModified = getLastModified(req);

//수정된 서블릿은 부가적 작업을 건너뛰네?

684

            if (lastModified == -1) {

685

                // servlet doesn't support if-modified-since, no reason

686

                // to go through further expensive logic

687

                doGet(req, resp);

688

            } else {

//어떤 경우에 일로 빠지는 거지? (maybeSetlastModified()가 변경하는건가?)

//나머진 내일 분석!!!!!

689

                long ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);

690

                if (ifModifiedSince < lastModified) {

691

                    // If the servlet mod time is later, call doGet()

692

                    // Round down to the nearest second for a proper compare

693

                    // A ifModifiedSince of -1 will always be less

694

                    maybeSetLastModified(resp, lastModified);

695

                    doGet(req, resp);

696

                } else {

697

                    resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);

698

                }

699

            }

700

701

        } else if (method.equals(METHOD_HEAD)) {

702

            long lastModified = getLastModified(req);

703

            maybeSetLastModified(resp, lastModified);

704

            doHead(req, resp);

705

706

        } else if (method.equals(METHOD_POST)) {

707

            doPost(req, resp);

708

709

        } else if (method.equals(METHOD_PUT)) {

710

            doPut(req, resp);

711

712

        } else if (method.equals(METHOD_DELETE)) {

713

            doDelete(req, resp);

714

715

        } else if (method.equals(METHOD_OPTIONS)) {

716

            doOptions(req,resp);

717

718

        } else if (method.equals(METHOD_TRACE)) {

719

            doTrace(req,resp);

720

721

        } else {

722

            //

723

            // Note that this means NO servlet supports whatever

724

            // method was requested, anywhere on this server.

725

            //

726

727

            String errMsg = lStrings.getString("http.method_not_implemented");

728

            Object[] errArgs = new Object[1];

729

            errArgs[0] = method;

730

            errMsg = MessageFormat.format(errMsg, errArgs);

731

732

            resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg);

733

        }

734

    }

735

736

737

    /*

738

     * Sets the Last-Modified entity header field, if it has not

739

     * already been set and if the value is meaningful.  Called before

740

     * doGet, to ensure that headers are set before response data is

741

     * written.  A subclass might have set this header already, so we

742

     * check.

743

     */

744

    private void maybeSetLastModified(HttpServletResponse resp,

745

                                      long lastModified) {

746

        if (resp.containsHeader(HEADER_LASTMOD))

747

            return;

748

        if (lastModified >= 0)

749

            resp.setDateHeader(HEADER_LASTMOD, lastModified);

750

    }
   
    
    

Dispatches client requests to the protected service method. There's no need to override this method.

Parameters:

req the HttpServletRequest object that contains the request the client made of the servlet

res the HttpServletResponse object that contains the response the servlet returns to the client

Throws:

java.io.IOException if an input or output error occurs while the servlet is handling the HTTP request

javax.servlet.ServletException if the HTTP request cannot be handled

See also:

javax.servlet.Servlet.service(javax.servlet.ServletRequest,javax.servlet.ServletResponse)

774

775

    @Override

776

    public void service(ServletRequest req, ServletResponse res)

777

        throws ServletException, IOException

778

    {

779

        HttpServletRequest  request;

780

        HttpServletResponse response;

781

782

        if (!(req instanceof HttpServletRequest &&

783

                res instanceof HttpServletResponse)) {

784

            throw new ServletException("non-HTTP request or response");

785

        }

786

787

        request = (HttpServletRequest) req;

788

        response = (HttpServletResponse) res;

789

790

        service(request, response);

791

    }

792

}

793

794

795

/*

796

 * A response that includes no body, for use in (dumb) "HEAD" support.

797

 * This just swallows that body, counting the bytes in order to set

798

 * the content length appropriately.  All other methods delegate directly

799

 * to the wrapped HTTP Servlet Response object.

800

 */

801

// file private

802

class NoBodyResponse extends HttpServletResponseWrapper {

803

804

    private static final ResourceBundle lStrings

805

        = ResourceBundle.getBundle("javax.servlet.http.LocalStrings");

806

807

    private NoBodyOutputStream noBody;

808

    private PrintWriter writer;

809

    private boolean didSetContentLength;

810

    private boolean usingOutputStream;

811

812

    // file private

813

    NoBodyResponse(HttpServletResponse r) {

814

        super(r);

815

        noBody = new NoBodyOutputStream();

816

    }

817

818

    // file private

819

    void setContentLength() {

820

        if (!didSetContentLength) {

821

            if (writer != null) {

822

                writer.flush();

823

            }

824

            setContentLength(noBody.getContentLength());

825

        }

826

    }

827

828

    @Override

829

    public void setContentLength(int len) {

830

        super.setContentLength(len);

831

        didSetContentLength = true;

832

    }

833

834

    @Override

835

    public void setContentLengthLong(long len) {

836

        super.setContentLengthLong(len);

837

        didSetContentLength = true;

838

    }

839

840

    @Override

841

    public void setHeader(String name, String value) {

842

        super.setHeader(name, value);

843

        checkHeader(name);

844

    }

845

846

    @Override

847

    public void addHeader(String name, String value) {

848

        super.addHeader(name, value);

849

        checkHeader(name);

850

    }

851

852

    @Override

853

    public void setIntHeader(String name, int value) {

854

        super.setIntHeader(name, value);

855

        checkHeader(name);

856

    }

857

858

    @Override

859

    public void addIntHeader(String name, int value) {

860

        super.addIntHeader(name, value);

861

        checkHeader(name);

862

    }

863

864

    private void checkHeader(String name) {

865

        if ("content-length".equalsIgnoreCase(name)) {

866

            didSetContentLength = true;

867

        }

868

    }

869

870

    @Override

871

    public ServletOutputStream getOutputStream() throws IOException {

872

873

        if (writer != null) {

874

            throw new IllegalStateException(

875

                lStrings.getString("err.ise.getOutputStream"));

876

        }

877

        usingOutputStream = true;

878

879

        return noBody;

880

    }

881

882

    @Override

883

    public PrintWriter getWriter() throws UnsupportedEncodingException {

884

885

        if (usingOutputStream) {

886

            throw new IllegalStateException(

887

                lStrings.getString("err.ise.getWriter"));

888

        }

889

890

        if (writer == null) {

891

            OutputStreamWriter w = new OutputStreamWriter(

892

                noBody, getCharacterEncoding());

893

            writer = new PrintWriter(w);

894

        }

895

896

        return writer;

897

    }

898

}

899

900

901

/*

902

 * Servlet output stream that gobbles up all its data.

903

 */

904

// file private

905

class NoBodyOutputStream extends ServletOutputStream {

906

907

    private static final String LSTRING_FILE =

908

        "javax.servlet.http.LocalStrings";

909

    private static ResourceBundle lStrings =

910

        ResourceBundle.getBundle(LSTRING_FILE);

911

912

    private int contentLength = 0;

913

914

    // file private

915

    NoBodyOutputStream() {}

916

917

    // file private

918

    int getContentLength() {

919

        return contentLength;

920

    }

921

922

    @Override

923

    public void write(int b) {

924

        contentLength++;

925

    }

926

927

    @Override

928

    public void write(byte buf[], int offset, int len)

929

        throws IOException

930

    {

931

        if (buf == null) {

932

            throw new NullPointerException(

933

                    lStrings.getString("err.io.nullArray"));

934

        }

935

936

        if (offset < 0 || len < 0 || offset+len > buf.length) {

937

            String msg = lStrings.getString("err.io.indexOutOfBounds");

938

            Object[] msgArgs = new Object[3];

939

            msgArgs[0] = Integer.valueOf(offset);

940

            msgArgs[1] = Integer.valueOf(len);

941

            msgArgs[2] = Integer.valueOf(buf.length);

942

            msg = MessageFormat.format(msg, msgArgs);

943

            throw new IndexOutOfBoundsException(msg);

944

        }

945

946

        contentLength += len;

947

    }

948

949

950

    public boolean isReady() {

951

        return false;

952

    }

953

954

    public void setWriteListener(WriteListener writeListener) {

955

956

    }

957

}