Java Servlet-获取客户端公共IP

我正在尝试通过servlet获取客户端

public

ip地址，如下所示：

        String ip = request.getHeader("X-Forwarded-For");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        System.out.println("1. ip: "+ip);
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        System.out.println("2. ip: "+ip);
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
        }
        System.out.println("3. ip: "+ip);
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }
        System.out.println("4. ip: "+ip);
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        System.out.println("4. ip: "+ip);

但这只能返回本地主机IP，如下面的输出所示：

1. ip: null
2. ip: null
3. ip: null
4. ip: null
4. ip: 127.0.0.1

---

有什么帮助吗？

这取决于代理服务器/负载平衡器及其配置。 在大多数情况下，通过以下方式获得IP是可能的

request.getHeader("x-forwarded-for") 

或

如果在您的服务器之前有代理服务器，请确保代理向您的服务器传递头，例如，在使用nginx的情况下，它应该是这样的

server {
  server_name  domain.com;
  ...
  location /path-to-server {
    ...
    proxy_pass  localhost:8080;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    ...
  }

---

我很喜欢这个，你可以试试

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;      
} 

---

找不到任何解决方案。接受的答案如何？我已经有了，它只返回本地主机ip。这只返回

null

value在您的服务器之前有哪个代理服务器，例如nginx？如果nginx确保它将所有头传递给服务器。nginx是否传递了所有头？你可以尝试在nginx中启用访问日志并检查客户端ip，然后在服务器中转储整个请求头并检查其中的内容。实际上，我可以看到

tomcat

无法将头发送到应用程序。。当我用

curl

测试时，我得到一个空标题

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;      
}