Java 获取客户端请求IP地址

import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class IPUtil {

    /**
     * 获取客户端的IP
     *
     * @param request request
     * @return ip
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("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.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;
    }

    /**
     * 获取客户端ip地址
     * @param request request
     * @return ip
     */
    public static String getIpAddr2(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;
    }

    /**
     * 获取客户端公网ip
     * @return ip
     */
    public static String getPublicIP() {
        String rspStr = HttpUtils.sendGet("https://www.taobao.com/help/getip.php", "json=true");
        if (StringUtils.isEmpty(rspStr)) {
            System.out.println("获取公网IP失败");
            return null;
        }
        List<String> ips = new ArrayList<String>();
        String regEx = "((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)";
        Pattern p = Pattern.compile(regEx);
        Matcher m = p.matcher(rspStr);
        while (m.find()) {
            String result = m.group();
            ips.add(result);
        }
        return ips.get(0);
    }

    /**
     * 获取客户端公网ip
     * @return ip
     */
    public static String getPublicIp() {
        try {
            String path = "http://www.net.cn/static/customercare/yourip.asp";// 要获得html页面内容的地址
            URL url = new URL(path);// 创建url对象
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();// 打开连接
            conn.setRequestProperty("contentType", "GBK"); // 设置url中文参数编码
            conn.setConnectTimeout(5 * 1000);// 请求的时间
            conn.setRequestMethod("GET");// 请求方式
            InputStream inStream = conn.getInputStream();
            BufferedReader in = new BufferedReader(new InputStreamReader(inStream, "GBK"));
            StringBuilder buffer = new StringBuilder();
            String line = "";
            // 读取获取到内容的最后一行,写入
            while ((line = in.readLine()) != null) {
                buffer.append(line);
            }
            List<String> ips = new ArrayList<String>();
            //用正则表达式提取String字符串中的IP地址
            String regEx = "((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)";
            String str = buffer.toString();
            Pattern p = Pattern.compile(regEx);
            Matcher m = p.matcher(str);
            while (m.find()) {
                String result = m.group();
                ips.add(result);
            }
            // 返回公网IP值
            return ips.get(0);

        } catch (Exception e) {
            System.out.println("获取公网IP连接超时");
            return null;
        }
    }
}