程序如下：这个header指的是什么啊？

Question

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class RequestHeaderExample extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
Enumeration e = request.getHeaderNames();
while (e.hasMoreElements()) {
String name = (String)e.nextElement();
String value = request.getHeader(name);
out.println(name + " = " + value);
}
}
}

Answer 1

getHeader("string")得到指定键值对里的值。getHeaderName()得到所有的键，并存在一个Enumeration枚举类型里。

Answer 2

getHeaderNames()Returns an enumeration of all the header names this request contains.刚查得API