java根据request 获取用户的真实ip，兼容有nginx 等反向代理的工具

/**
	 * 获取客户端的IP地址
	 * 
	 * @return
	 */
	public static String getIp(HttpServletRequest request) {
		String ipAddress = null;
		// ipAddress = this.getRequest().getRemoteAddr();
		
		ipAddress = request.getHeader("X-Real-IP");
		
		if(ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getHeader("x-forwarded-for");
		} 
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getHeader("Proxy-Client-IP");
		} 
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getHeader("WL-Proxy-Client-IP");
		} 
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.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()
			if (ipAddress.indexOf(",") > 0) {
				ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
			}
		}
		System.out.println("ip为:"+ipAddress);
		return ipAddress;
	}