java 获取HttpRequest Header的几种方法(必看篇)

在开发应用程序的过程中，如果有多个应用，通常会通过一个portal 门户来集成，这个portal  是所有应用程序的入口，用户一旦在portal 登录之后，进入另外一个系统，就需要类似的单点登录(sso). 进入各个子系统的时候，就不需要再次登录, 当然类似的功能，你可以通过专业的单点登录软件来实现，也可以自己写数据库token 等方式来实现。其实还有一个比较简单的方法，就是通过 portal 封装已经登录过的用户的消息，写到http header 之中，然后把请求forward 到各个子系统中去，而各子系统从 http header 中获取用户名，作为是否登录过的校验或者合法的校验。

总结了几种处理http header 的方法：

利用 httpservletrequest

import javax.servlet.http.httpservletrequest;
 //...
 private httpservletrequest request;
 //get request headers
 private map<string, string> getheadersinfo() {
  map<string, string> map = new hashmap<string, string>();
  enumeration headernames = request.getheadernames();
  while (headernames.hasmoreelements()) {
    string key = (string) headernames.nextelement();
    string value = request.getheader(key);
    map.put(key, value);
  }
  return map;
 }

一个典型的例子如下：

"headers" : {
  "host" : "yihaomen.com",
  "accept-encoding" : "gzip,deflate",
  "x-forwarded-for" : "66.249.x.x",
  "x-forwarded-proto" : "http",
  "user-agent" : "mozilla/5.0 (compatible; googlebot/2.1; +
http://www.google.com/bot.html
)",
  "x-request-start" : "1389158003923",
  "accept" : "*/*",
  "connection" : "close",
  "x-forwarded-port" : "80",
  "from" : "googlebot(at)googlebot.com"
}

获取 user-agent

import javax.servlet.http.httpservletrequest;
 //...
 private httpservletrequest request;
 private string getuseragent() {
  return request.getheader("user-agent");
 }

一个典型的例子如下：

mozilla/5.0 (compatible; googlebot/2.1; +
http://www.google.com/bot.html
)

利用 spring mvc 获取  httprequest header 的例子

import java.util.enumeration;
import java.util.hashmap;
import java.util.map;
import javax.servlet.http.httpservletrequest;
import org.springframework.beans.factory.annotation.autowired;
import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.servlet.modelandview;
@controller
@requestmapping("/site")
public class sitecontroller {
  @autowired
  private httpservletrequest request;
  @requestmapping(value = "/{input:.+}", method = requestmethod.get)
  public modelandview getdomain(@pathvariable("input") string input) {
    modelandview modelandview = new modelandview("result");
    modelandview.addobject("user-agent", getuseragent());
    modelandview.addobject("headers", getheadersinfo());
    return modelandview;
  }
  //get user agent
  private string getuseragent() {
    return request.getheader("user-agent");
  }
  //get request headers
  private map<string, string> getheadersinfo() {
    map<string, string> map = new hashmap<string, string>();
    enumeration headernames = request.getheadernames();
    while (headernames.hasmoreelements()) {
      string key = (string) headernames.nextelement();
      string value = request.getheader(key);
      map.put(key, value);
    }
    return map;
  }
}

也许有人会说，http header  是可以模拟的，那么自己可以构造一个用来欺骗这些系统， 是的，的确是这样，所以在用http header 来传值得时候，一定要记得，所有的请求都必须经过 portal 来处理，然后 forward 到各子系统，就不会出现这个问题了。因为portal 首先拦截用户发起的所有的请求，如果是构造的用户，在portal 的sessiion 也是没有记录的，仍然会跳转到登录页面，如果在protal 的 session 中记录，而且  http header 中也有记录，那么在子系统就是合法的用户，然后自己可以根据一些要求处理业务逻辑了

jsp/java获取http header信息(request)例子

<%
//header.jsp
out.println("protocol: " + request.getprotocol() + "<br>");
out.println("scheme: " + request.getscheme() + "<br>");
out.println("server name: " + request.getservername() + "<br>" );
out.println("server port: " + request.getserverport() + "<br>");
out.println("protocol: " + request.getprotocol() + "<br>");
out.println("server info: " + getservletconfig().getservletcontext().getserverinfo() + "<br>");
out.println("remote addr: " + request.getremoteaddr() + "<br>");
out.println("remote host: " + request.getremotehost() + "<br>");
out.println("character encoding: " + request.getcharacterencoding() + "<br>");
out.println("content length: " + request.getcontentlength() + "<br>");
out.println("content type: "+ request.getcontenttype() + "<br>");
out.println("auth type: " + request.getauthtype() + "<br>");
out.println("http method: " + request.getmethod() + "<br>");
out.println("path info: " + request.getpathinfo() + "<br>");
out.println("path trans: " + request.getpathtranslated() + "<br>");
out.println("query string: " + request.getquerystring() + "<br>");
out.println("remote user: " + request.getremoteuser() + "<br>");
out.println("session id: " + request.getrequestedsessionid() + "<br>");
out.println("request url: " + request.getrequesturl() + "<br>");
out.println("request uri: " + request.getrequesturi() + "<br>");
out.println("servlet path: " + request.getservletpath() + "<br>");
out.println("created : " + session.getcreationtime() + "<br>");
out.println("lastaccessed : " + session.getlastaccessedtime() + "<br>");

out.println("accept: " + request.getheader("accept") + "<br>");
out.println("host: " + request.getheader("host") + "<br>");
out.println("referer : " + request.getheader("referer") + "<br>");
out.println("accept-language : " + request.getheader("accept-language") + "<br>");
out.println("accept-encoding : " + request.getheader("accept-encoding") + "<br>");
out.println("user-agent : " + request.getheader("user-agent") + "<br>");
out.println("connection : " + request.getheader("connection") + "<br>");
out.println("cookie : " + request.getheader("cookie") + "<br>");
%>

关于request.getheader("referer")的说明

request.getheader("referer")获取来访者地址。只有通过链接访问当前页的时候，才能获取上一页的地址；否则request.getheader("referer")的值为null，通过window.open打开当前页或者直接输入地址，也为null。

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