String t = new String(request.getParameter("d").getBytes("ISO8859-1"), "Cp1251");
  

 
requestEnc = request.getCharacterEncoding();
 if (requestEnc ==  null ) requestEnc = "ISO-8859-1";
String clientEnc = request.getParameter("charset");
 if (clientEnc ==  null ) clientEnc = "Cp1251";
response.setContentType("text/html");
PrintWriter out = response.getWriter();
   //...
String value =  new  String(request.getParameter(namesArray[i]).getBytes(requestEnc),clientEnc);
  //namesArray - массив всех "name" input'ов формы
out.println("..." + value + "...");