=============
后端_实用工具
=============

1 从上下文中获取HttpServletRequest对象

/ysdblog-api/src/main/java/com/weihome/ysdblog/utils/HttpContextUtils.java：

public class HttpContextUtils {
    public static HttpServletRequest getHttpServletRequest() {
        return ((ServletRequestAttributes) RequestContextHolder
            .getRequestAttributes()).getRequest();
    }
}

2 从HttpServletRequest对象中获取源IP

/ysdblog-api/src/main/java/com/weihome/ysdblog/utils/IPUtils.java：

public class IPUtils {
	/**
	 * 获取IP地址
	 * 使用反向代理， 不能通过getRemoteAddr()获取IP地址
	 * 多级反向代理，X-Forwarded-For的值不止一个，第一个有效IP即为真实IP
	 */
	public static String getIpAddr(HttpServletRequest request) {
		String ip = request.getHeader("x-forwarded-for");

		if (StringUtils.isEmpty(ip) ||
			"unknown".equalsIgnoreCase(ip))
			ip = request.getHeader("Proxy-Client-IP");

		if (StringUtils.isEmpty(ip) || ip.length() == 0 ||
			"unknown".equalsIgnoreCase(ip))
			ip = request.getHeader("WL-Proxy-Client-IP");

		if (StringUtils.isEmpty(ip) ||
			"unknown".equalsIgnoreCase(ip))
			ip = request.getHeader("HTTP_CLIENT_IP");

		if (StringUtils.isEmpty(ip) ||
			"unknown".equalsIgnoreCase(ip))
			ip = request.getHeader("HTTP_X_FORWARDED_FOR");

		if (StringUtils.isEmpty(ip) ||
			"unknown".equalsIgnoreCase(ip))
			ip = request.getRemoteAddr();

		if (ip.length() > 15 && ip.indexOf(",") > 0)
			ip = ip.substring(0, ip.indexOf(","));

		return ip;
	}
}