Dynamic Content Type Settings

For situations where the appropriate content type for the HTTP response is not known until runtime, you can set it dynamically in the JSP page. The standard javax.servlet.ServletResponse interface specifies the following method for this purpose:

public void setContentType(java.lang.String contenttype)

The implicit response object of a JSP page is a javax.servlet.http.HttpServletResponse instance, where the HttpServletResponse interface extends the ServletResponse interface.

The setContentType() method input, like the contentType setting in a page directive, can include a MIME type only, or both a character set and a MIME type. For example:

response.setContentType("text/html; charset=UTF-8");

or:

response.setContentType("text/html");

As with a page directive, the default MIME type is text/html and the default character encoding is ISO-8859-1.

This method has no effect on interpreting the text of the JSP page during translation. If a particular character set is required during translation, that must be specified in a page directive, as described in "Content Type Settings in the page Directive".

Be aware of the following important usage notes:

• The JSP page cannot be unbuffered if you are using the setContentType() method. (It is buffered by default; do not set buffer="none" in a page directive.)

• The setContentType() call must appear early in the page, before any output to the browser or any jsp:include command (which flushes the JSP buffer to the browser).

• In servlet 2.2 environments, the response object has a setLocale() method that sets a default character set based on the specified locale, overriding any previous character set. For example, the following method call results in a character set of Shift_JIS:

  response.setLocale(new Locale("ja", "JP"));
  

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