获取访问者主机的IP地址

 方法一:

public static String getIpAddr(HttpServletRequest request){
        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 || "unknown".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")){
                //根据网卡取本机配置的IP
                InetAddress inet=null;
                try {
                    inet = InetAddress.getLocalHost();
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                }
                ipAddress= inet.getHostAddress();
            }
        }
        //对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        if(ipAddress!=null && ipAddress.length()>15){ //"***.***.***.***".length() = 15
            if(ipAddress.indexOf(",")>0){
                ipAddress = ipAddress.substring(0,ipAddress.indexOf(","));
            }
        }
        return ipAddress;
    }

方法二:

/** 
	 * 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址; 
	 *  
	 * @param request 
	 * @return 
	 * @throws IOException
	 */  
	public final static String getIpAddress(HttpServletRequest request) {
		// 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址  

		String ip = request.getHeader("X-Forwarded-For");

		if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
			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.getHeader("HTTP_CLIENT_IP");  
			}  
			if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
				ip = request.getHeader("HTTP_X_FORWARDED_FOR");  
			}  
			if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
				ip = request.getRemoteAddr();  
			}  
		} else if (ip.length() > 15) {  
			String[] ips = ip.split(",");
			for (int index = 0; index < ips.length; index++) {  
				String strIp = ips[index];
				if (!("unknown".equalsIgnoreCase(strIp))) {  
					ip = strIp;  
					break;  
				}  
			}  
		}  
		return ip;  
	}  

上面这是两个人的方法。采用哪种都可以