tomcat5下jsp出现getOutputStream() has already been called for this response
转自:http://blog.csdn.net/alexwan/archive/2007/02/13/1508871.aspx

jsp编译成servlet 有
finally {
      if (_jspxFactory != null) _jspxFactory.releasePageContext(_jspx_page_context);
    }
释放资源,调用request.getWriter();
与response.getOutputStream();冲突

解决:用完流调用
out.clear();
out = pageContext.pushBody();