Java获取IP地址:request.getRemoteAddr()警惕
- public String getRemortIP(HttpServletRequest request) {
- if (request.getHeader("x-forwarded-for") == null) {
- return request.getRemoteAddr();
- }
- return request.getHeader("x-forwarded-for");
- }
可是当我访问http://www.xxx.com/index.jsp/ 时,返回的IP地址始终是unknown,也并不是如上所示的127.0.0.1 或 192.168.1.110 了,而我访问http://192.168.1.110:2046/index.jsp 时, 则能返回客户端的真实IP地址,写了个方法去验证。原因出在了Squid上。squid.conf 的配制文件 forwarded_for 项默认是为on,如果 forwarded_for 设成了 off 则:X-Forwarded-For: unknown
于是可得出获得客户端真实IP地址的方法二:
- public String getIpAddr(HttpServletRequest request) {
- String ip = request.getHeader( " x-forwarded-for " );
- if (ip == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip)) {
- ip = request.getHeader( " Proxy-Client-IP " );
- }
- if (ip == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip)) {
- ip = request.getHeader( " WL-Proxy-Client-IP " );
- }
- if (ip == null || ip.length() == 0 || " unknown " .equalsIgnoreCase(ip)) {
- ip = request.getRemoteAddr();
- }
- return ip;
- }
可是,如果通过了多级反向代理的话,X-Forwarded-For的值并不止一个,而是一串Ip值,究竟哪个才是真正的用户端的真实IP呢?
答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
如:
X-Forwarded-For:192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100
用户真实IP为: 192.168.1.110
说明:按这种方法不一定100%准,网上很多人提到要准确的话必须做一个客户端空间,如applet。
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