Java获取客户端的真实IP地址

像移动网关一样，iisforward这个ISAPI过滤器也会对request对象进行再包装，附加一些WLS要用的头信息。这种情况下，直接用request.getRemoteAddr()是无法取到真正的客户IP的。

实际的iisforward附加头如下：

WL-Proxy-Client-IP=211.161.1.239  
Proxy-Client-IP=211.161.1.239  
X-Forwarded-For=211.161.1.239  
WL-Proxy-Client-Keysize=   
WL-Proxy-Client-Secretkeysize=   
X-WebLogic-Request-ClusterInfo=true  
X-WebLogic-KeepAliveSecs=30  
X-WebLogic-Force-JVMID=-327089098  
WL-Proxy-SSL=false  

综上，正确作法如下：

private String getIpAddr() {   
     String ipAddress = null;   
     //ipAddress = this.getRequest().getRemoteAddr();   
     ipAddress = this.getRequest().getHeader("x-forwarded-for");   
     if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {   
      ipAddress = this.getRequest().getHeader("Proxy-Client-IP");   
     }   
     if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {   
         ipAddress = this.getRequest().getHeader("WL-Proxy-Client-IP");   
     }   
     if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {   
      ipAddress = this.getRequest().getRemoteAddr();   
      if(ipAddress.equals("127.0.0.1")){   
       //根据网卡取本机配置的IP   
       InetAddress inet=null;   
    try {   
     inet = InetAddress.getLocalHost();   
    } catch (UnknownHostException e) {   
     e.printStackTrace();   
    }   
    ipAddress= inet.getHostAddress();   
      }   
            
     }   
  
     //对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割   
     if(ipAddress!=null && ipAddress.length()>15){ //"***.***.***.***".length() = 15   
         if(ipAddress.indexOf(",")>0){   
             ipAddress = ipAddress.substring(0,ipAddress.indexOf(","));   
         }   
     }   
     return ipAddress;    
  }   

转载出自： http://newleague.iteye.com/blog/858741