You can specify the encoding of an HTML page in the Content-Type HTTP header in a JavaServer Pages (JSP) file using the contentType page directive. For example:
<%@ page contentType="text/html; charset=utf-8" %>
This is the MIME type and character encoding that the JSP file uses for the response it sends to the client. You can use any MIME type or IANA character set name that is valid for the JSP container. The default MIME type is text/html, and the default character set is ISO-8859-1. In the above example, the character set is set to UTF-8. The character set of the contentType page directive directs the JSP engine to encode the dynamic HTML page and set the HTTP Content-Type header with the specified character set.
For Java Servlets, you can call the setContentType method of the Servlet API to specify a page encoding in the HTTP header. The doGet function in Example 9-6 shows how you can call this method.
You should call the setContentType method before the getWriter method because the getWriter method initializes an output stream writer that uses the character set specified by the setContentType method call. Any HTML content written to the writer and eventually to a browser is encoded in the encoding specified by the setContentType call.
Example 9-6 Specifying Page Encoding in Servlets Using setContentType
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
// generate the MIME type and character set header
response.setContentType("text/html; charset=utf-8");
...
// generate the HTML page
Printwriter out = response.getWriter();
out.println("<HTML>");
...
out.println("</HTML>");
}