jsp页面采用utf-8编码,为什么<%@ include file="comm/no-cache.jsp"%>会出错?

Question

comm/no-cache.jsp的内容为:
<%
response.setDateHeader("Expires", 0);
response.setHeader("Pragma", "no-cache");
if(request.getProtocol().equals("HTTP/1.1"))
response.setHeader("Cache-Control", "no-cache");
%>
我把这些内容复制到原来的页面,代替<%@ include file="comm/no-cache.jsp"%>就不会错.

Answer 1

到tomcat的work目录看jsp的.java文件,发现
        try {
      _jspxFactory = JspFactory.getDefaultFactory();
      response.setContentType("text/html;charset=utf-8");
      pageContext = _jspxFactory.getPageContext(this, request, response,
       null, true, 8192, true);
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      session = pageContext.getSession();
      out = pageContext.getOut();
      _jspx_out = out;      out.write('&#65279;<>(');
      out.write('?(');
      out.write('?&'); response.setDateHeader("Expires", 0);
response.setHeader("Pragma", "no-cache");
if(request.getProtocol().equals("HTTP/1.1"))
response.setHeader("Cache-Control", "no-cache");      out.write(")$>");开头的地方会打印乱码出来.
如果在调用的jsp页面,写 <%@ page contentType="text/html; charset=utf-8"%>
会报编码重复的错误.