假定你的web application 名称为news,你在浏览器中输入请求路径：
http://localhost:8080/news/main/list.jsp
则执行下面向行代码后打印出如下结果：
1、 System.out.println(request.getContextPath());
打印结果：/news
2、System.out.println(request.getServletPath());
打印结果：/main/list.jsp
3、 System.out.println(request.getRequestURI());
打印结果：/news/main/list.jsp
4、System.out.println(request.getRequestURL());
打印结果：http://localhost:8080/news/main/list.jsp
5、 System.out.println(request.getRealPath("/"));
打印结果：F:\Tomcat 6.0\webapps\news\test
6 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。
1. private String 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. }
25.
26. //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
27. if(ipAddress!=null && ipAddress.length()>15){ //"***.***.***.***".length() = 15
28. if(ipAddress.indexOf(",")>0){
29. ipAddress = ipAddress.substring(0,ipAddress.indexOf(","));
30. }
31. }
32. return ipAddress;
33. }