java获取客户端真实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：

1. WL-Proxy-Client-IP=211.161.1.239
2. Proxy-Client-IP=211.161.1.239
3. X-Forwarded-For=211.161.1.239
4. WL-Proxy-Client-Keysize=
5. WL-Proxy-Client-Secretkeysize=
6. X-WebLogic-Request-ClusterInfo=true
7. X-WebLogic-KeepAliveSecs=30
8. X-WebLogic-Force-JVMID=-327089098
9. WL-Proxy-SSL=false

综上，正确作法如下：

1. privateString getIpAddr() {
2. String ipAddress = null;
3. //ipAddress =this.getRequest().getRemoteAddr();
4. ipAddress = this.getRequest().getHeader("x-forwarded-for");
5. if(ipAddress== null ||ipAddress.length() == 0|| "unknown".equalsIgnoreCase(ipAddress)){
6. ipAddress = this.getRequest().getHeader("Proxy-Client-IP");
7. }
8. if(ipAddress ==null || ipAddress.length()== 0 ||"unknown".equalsIgnoreCase(ipAddress)){
9. ipAddress = this.getRequest().getHeader("WL-Proxy-Client-IP");
10. }
11. if(ipAddress== null ||ipAddress.length() == 0|| "unknown".equalsIgnoreCase(ipAddress)){
12. ipAddress = this.getRequest().getRemoteAddr();
13. if(ipAddress.equals("127.0.0.1")){
14. //根据网卡取本机配置的IP
15. InetAddress inet=null;
16. try {
17. inet =InetAddress.getLocalHost();
18. } catch(UnknownHostException e) {
19. e.printStackTrace();
20. }
21. ipAddress= inet.getHostAddress();
22. }
23. }
24. //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
25. if(ipAddress!=null &&ipAddress.length()>15){ //"***.***.***.***".length() = 15
26. if(ipAddress.indexOf(",")>0){
27. ipAddress =ipAddress.substring(0,ipAddress.indexOf(","));
28. }
29. }
30. returnipAddress;
31. }