java 擷取使用者真實ip位址

String ipAddress = request.getHeader("x-forwarded-for");
		          
		          if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
		              ipAddress = request.getHeader("Proxy-Client-IP");
		          }
		          if (ipAddress == null || ipAddress.length() == 0 || "unknow".equalsIgnoreCase(ipAddress)) {
		              ipAddress = request.getHeader("WL-Proxy-Client-IP");
		         }
		         if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
		             ipAddress = request.getRemoteAddr();
		             
		             if(ipAddress.equals("127.0.0.1") || ipAddress.equals("0:0:0:0:0:0:0:1")){
		                 //根據網卡擷取本機配置的IP位址
		                 InetAddress inetAddress = null;
		                 try {
		                     inetAddress = InetAddress.getLocalHost();
		                 } catch (UnknownHostException e) {
		                     e.printStackTrace();
		                 }
		                 ipAddress = inetAddress.getHostAddress();
		             }
		         }
		         
		         //對于通過多個代理的情況，第一個IP為用戶端真實的IP位址，多個IP按照','分割
		         if(null != ipAddress && ipAddress.length() > 15){
		             //"***.***.***.***".length() = 15
		             if(ipAddress.indexOf(",") > 0){
		                 ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
		             }
		         }
		         System.out.println(ipAddress);