官方说明：
例子：
虚拟机ip：192.168.85.3，物理机VMware Network Adapter VMnet8 ip：192.168.85.1
1，准备tomcat
准备一tomcat，端口，8080
准备一Jsp，用于获取客户端真实IP和nginx IP ，test.jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Test Page</title>
</head>
<body>
Test1 Page!!!<br/>
remote ip : <%-- <%=request.getHeader("X-real-ip") %> --%> <br/>
nginx server ip : <%=request.getRemoteAddr()%>
</body>
</html>
将test.jsp 上传到 tomcat的/ROOT目录下。
2，配置nginx
注意，反向代理之后获取到客户端IP地址为nginx服务器地址，这里需要nginx进行forward，设置真实的ip地址。往请求头set一变量 X-real-ip ,值取客户端ip，这样就可以在jsp中获取该变量：
proxy_set_header X-real-ip $remote_addr;
匹配.jsp结尾的请求：
location ~ \.jsp$
3，测试
启动tomcat，启动nginx，浏览器访问：http://192.168.85.3:70/test.jsp
在Java里面一般有一个工具类来获取 IP：
public class IpUtils {
private IpUtils() {
}
public static String getIpAddr(HttpServletRequest request) {
if (request == null) {
return "unknown";
}
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("X-Forwarded-For");
}
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.getHeader("X-Real-IP");
}
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getRemoteAddr();
}
return ip;
}
}