Utils：获取请求客户端的真实IP地址

获取真实 IP 地址。一次项目中有记录请求方的 IP，某天收集到的 IP 地址全是相同的，后面定位到问题是在阿里云启用了 SLB（负载均衡），收集到的全是负载均衡服务器的 IP，而不是用户端的 IP，后面改为判断从 x-forwarded-for 中取。

真实IP

1. 获取真实 IP 地址

   package utils;
   
   import javax.servlet.http.HttpServletRequest;
   import java.util.StringTokenizer;
   import java.util.regex.Pattern;
   
   public class IPUtil {
   
       public static final String _255 = "(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)";
       public static final Pattern pattern = Pattern.compile("^(?:" + _255 + "\\.){3}" + _255 + "$");
   
       /**
        * 获取IP地址普通方式
        *
        * @param request
        * @return
        */
       public String getIpAddr(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 longToIpV4(long longIp) {
           int octet3 = (int) ((longIp >> 24) % 256);
           int octet2 = (int) ((longIp >> 16) % 256);
           int octet1 = (int) ((longIp >> 8) % 256);
           int octet0 = (int) ((longIp) % 256);
           return octet3 + "." + octet2 + "." + octet1 + "." + octet0;
       }
   
       public static long ipV4ToLong(String ip) {
           String[] octets = ip.split("\\.");
           return (Long.parseLong(octets[0]) << 24) + (Integer.parseInt(octets[1]) << 16)
                   + (Integer.parseInt(octets[2]) << 8) + Integer.parseInt(octets[3]);
       }
   
       public static boolean isIPv4Private(String ip) {
           long longIp = ipV4ToLong(ip);
           return (longIp >= ipV4ToLong("10.0.0.0") && longIp <= ipV4ToLong("10.255.255.255"))
                   || (longIp >= ipV4ToLong("172.16.0.0") && longIp <= ipV4ToLong("172.31.255.255"))
                   || longIp >= ipV4ToLong("192.168.0.0") && longIp <= ipV4ToLong("192.168.255.255");
       }
   
       public static boolean isIPv4Valid(String ip) {
           return pattern.matcher(ip).matches();
       }
   
       /**
        * 更完善的获取IP地址
        * @param request
        * @return
        */
       public static String getIpFromRequest(HttpServletRequest request) {
           String ip;
           boolean found = false;
           if ((ip = request.getHeader("x-forwarded-for")) != null) {
               StringTokenizer tokenizer = new StringTokenizer(ip, ",");
               while (tokenizer.hasMoreTokens()) {
                   ip = tokenizer.nextToken().trim();
                   if (isIPv4Valid(ip) && !isIPv4Private(ip)) {
                       found = true;
                       break;
                   }
               }
           }
           if (!found) {
               ip = request.getRemoteAddr();
           }
           return ip;
       }
   }
   

2. 从请求头中获取IP 地址，IP地址是可被改变的。

   $.ajax({
       type : "GET",
       headers : {"X-Forwarded-For":randomIp,"WL-Proxy-Client-IP":randomIp},
       contentType : 'application/x-www-form-urlencoded;charset=utf-8',
       url : url,
       data:params,
       dataType : "text",
       success : function(data) {
           count++;
           console.log("时间：【"+new Date()+"】 执行成功：【"+count+"】次："+data);
       if(max>0){
           setTimeout(function wait(){
               console.log("等待"+(timeWait)+"ms ...");
               vote(max,getRandomNum(maxWait,minWait));
           },timeWait);
       }
       }
   
   }
   

3. Nginx 反向代理设置头信息中的远程IP地址

   Nginx 反身代理设置，将 X-Forward-For 替换为 remote_addr

   #Nginx 设置
   location  ~  ^/static {
   proxy_pass  ....;
   proxy_set_header X-Forward-For $remote_addr ;
   }
   

4. 另一种方式获取IP

   public class IPUtil {
   
       public static String getIPAddress(HttpServletRequest request) {
           String ip = null;
   
           //X-Forwarded-For：Squid 服务代理
           String ipAddresses = request.getHeader("X-Forwarded-For");
   
           if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
               //Proxy-Client-IP：apache 服务代理
               ipAddresses = request.getHeader("Proxy-Client-IP");
           }
   
           if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
               //WL-Proxy-Client-IP：weblogic 服务代理
               ipAddresses = request.getHeader("WL-Proxy-Client-IP");
           }
   
           if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
               //HTTP_CLIENT_IP：有些代理服务器
               ipAddresses = request.getHeader("HTTP_CLIENT_IP");
           }
   
           if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
               //X-Real-IP：nginx服务代理
               ipAddresses = request.getHeader("X-Real-IP");
           }
   
           //有些网络通过多层代理，那么获取到的ip就会有多个，一般都是通过逗号（,）分割开来，并且第一个ip为客户端的真实IP
           if (ipAddresses != null && ipAddresses.length() != 0) {
               ip = ipAddresses.split(",")[0];
           }
   
           //还是不能获取到，最后再通过request.getRemoteAddr();获取
           if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
               ip = request.getRemoteAddr();
           }
           return ip;
       }
   }
   

参考资料

1. 正确获取真实的 IP地址