Response 구간 정리

Response객체는 브라우저에 전달되는 HTML 결과 생성할 때 사용된다. Response객체의 Encoding CharterSet에 따라서 브라우저에서 출력되는 한글이 깨져보일수 있으므로 주위를 해야 한다. 하지만 걱정할 필요는 없다.
아래 제시되는 3가지 방법중 한 가지만 제대로 해도 한글 출력에 문제가 없다.  

qResponse Charset에 따라서 출력되는 HTML Body의 charset에 영향을 미치게 된다.

qCharter set을 명시적으로 지정하라.

¤대략 3가지 방법으로 설정 가능하며 같은 효과가 있다.

1.Page 설정 통해서 설정

¡<%@ page pageEncoding="UTF-8" contentType="text/html;charset=UTF-8" %>

¡pageEncoding 생략시 charset에 따라서 Page Encoding 됨

2.함수 호출 1
Response.setCharacterEncoding(“UTF-8”);
Response.setContentType("text/html");

3.함수 호출 2
Response.setContentType("text/html;charset=UTF-8");

¤방법 1,2,3 중복해서 호출될 경우, 마지막 호출된 값이 유효하다.

¤하지만 PrintWriter pw = response.getWriter(); 함수 호출 이후에는 setCharacterEncoding(), setContentType() 함수가 호출되어도 무시된다.  

q명시적으로 Charset을 설정하지 않았다면 아래 단계로 디폴트 값 설정 됨

1.HTTP Request의 Content-Language 참조

2.<locale-encoding-mapping-list> 정보를 web.xml에서 찾는다.

3.ISO-8859-1 을 사용한다.

qSRV.5.4 Response data Encoding ( servlet-2_5-mrel2-spec.pdf 에서 발췌 )

Servlets should set the locale and the character encoding of a response. The locale is set using the ServletResponse.setLocale method. The method can be called repeatedly; but calls made after the response is committed have no effect. If the servlet does not set the locale before the page is committed, the container’s default locale is used to determine the response’s locale, but no specification is made for the communication with a client, such as Content-Language header in the case of HTTP.

<locale-encoding-mapping-list>

<locale-encoding-mapping>

<locale>ja</locale>

<encoding>Shift_JIS</encoding>

</locale-encoding-mapping>

</locale-encoding-mapping-list>

If the element does not exist or does not provide a mapping, setLocale uses a container dependent mapping. The setCharacterEncoding, setContentType, and setLocale methods can be called repeatedly to change the character encoding.

Calls made after the servlet response’s getWriter method has been called or after the response is committed have no effect on the character encoding. Calls to setContentType set the character encoding only if the given content type string

provides a value for the charset attribute. Calls to setLocale set the character encoding only if neither setCharacterEncoding nor setContentType has set the character encoding before.

If the servlet does not specify a character encoding before the getWriter method of the ServletResponse interface is called or the response is committed, the default ISO-8859-1 is used.

Containers must communicate the locale and the character encoding used for the servlet response’s writer to the client if the protocol in use provides a way for doing so. In the case of HTTP, the locale is communicated via the Content-Language header, the character encoding as part of the Content-Type header for text media types. Note that the character encoding cannot be communicated via

HTTP headers if the servlet does not specify a content type; however, it is still

used to encode text written via the servlet response’s writer.