import java.net.InetAddress;
import java.net.UnknownHostException;

import javax.servlet.http.HttpServletRequest;

public class ToolIP {
    /**
     * 
功能:获取本地IP
     * 如果没有获取到本地IP则返回0.0.0.0
     * 
     * @return 本地IP地址
     */
    public static String getLocalIpAddr() {
        String localIpAddr;
        try {
            localIpAddr = InetAddress.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
            localIpAddr = "0.0.0.0";
        }
        return localIpAddr;
    }

     /** 
     * 获取用户真实IP地址，不使用request.getRemoteAddr()的原因是有可能用户使用了代理软件方式避免真实IP地址, 
     * 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 
     *  
     * @return ip
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for"); 
        if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {  
            // 多次反向代理后会有多个ip值，第一个ip才是真实ip
            if( ip.indexOf(",")!=-1 ){
                ip = ip.split(",")[0];
            }
        }  
        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.getHeader("X-Real-IP");  
        }  
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  
            ip = request.getRemoteAddr();  
        } 
        return ip;  
    }
}

网页名称：获取IP地址工具类
文章网址：http://kswjz.com/article/gdjohs.html