java获取客户端请求IP地址（公网ip）

之前写了一个获取ip地址的方法，但是放网上一查显示此Ip地址是局域网ip地址，要是想获取请求端的真实公网ip地址怎么样了，看了一些别人的博客后发现，想要获取客户端的公网ip必须借助第三方。

package com.jzproject.common.util;

import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;

/**
 * 
 * @Description：IP工具类
 * @author zrt
 * @date 2018年9月22日 上午10:38:13
 */
public class IPUtil {

   private static final Logger logger = LoggerFactory.getLogger(IPUtil.class);

   /**
    * 
    * @Description：获取客户端的IP
    * @author zrt
    * @date 2018年9月22日 上午10:39:44
    */
    public static String getIpAddress(HttpServletRequest request) {
       //注意本地测试时，浏览器请求不要用localhost，要用本机IP访问项目地址，不然这里取不到ip
       // 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 (logger.isInfoEnabled()) {
            logger.info("getIpAddress(HttpServletRequest) - X-Forwarded-For - String ip=" + ip);
        }

        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 (logger.isInfoEnabled()) {
                    logger.info("getIpAddress(HttpServletRequest) - Proxy-Client-IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
                if (logger.isInfoEnabled()) {
                    logger.info("getIpAddress(HttpServletRequest) - WL-Proxy-Client-IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
                if (logger.isInfoEnabled()) {
                    logger.info("getIpAddress(HttpServletRequest) - HTTP_CLIENT_IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
                if (logger.isInfoEnabled()) {
                    logger.info("getIpAddress(HttpServletRequest) - HTTP_X_FORWARDED_FOR - String ip=" + ip);
                }
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
                if (logger.isInfoEnabled()) {
                    logger.info("getIpAddress(HttpServletRequest) - getRemoteAddr - String ip=" + ip);
                }
            }
        } else if (ip.length() > 15) {
            String[] ips = ip.split(",");
            for (int index = 0; index < ips.length; index++) {
                String strIp = (String) ips[index];
                if (!("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }

    public static void main(String[] args) throws Exception {

        System.err.println("公网ipppppppppppp:" + getPublicIp());

    }

    /**
     * @Description：获取客户端外网ip
     * @Author：zrt
     * @Date：2019/6/13 11:23
     **/
    public static String getPublicIp() {
        try {
            String path = "http://iframe.ip138.com/ic.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();
            // readLesoSysXML(inStream);

            BufferedReader in = new BufferedReader(new InputStreamReader(
                    inStream, "GBK"));
            StringBuffer buffer = new StringBuffer();
            String line = "";
            // 读取获取到内容的最后一行,写入
            while ((line = in.readLine()) != null) {
                buffer.append(line);
            }
            String str = buffer.toString();
            String ipString1 = str.substring(str.indexOf("["));
            // 获取你的IP是中间的[182.149.82.50]内容
            String ipsString2 = ipString1.substring(ipString1.indexOf("[") + 1,
                    ipString1.lastIndexOf("]"));
            //获取当前IP地址所在地址
      /* String ipsString3=ipString1.substring(ipString1.indexOf(": "),ipString1.lastIndexOf("</center>"));
         System.err.println(ipsString3);*/

            // 返回公网IP值
            return ipsString2;

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

}