获取访问者的IP

import java.io.Serializable;
import java.net.InetAddress;
import java.net.UnknownHostException;

import javax.servlet.http.HttpServletRequest;

public class IpUtil implements Serializable {
private static final long serialVersionUID = -2714197398219631534L;

public static String getIpAddrByRequest(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;

}

public static String getIpAddr(HttpServletRequest request) {
String ipAddress = null;
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();

// 这里主要是获取本机的ip,可有可无
if (ipAddress.equals("127.0.0.1")
|| ipAddress.endsWith("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;
}
}