JavaWeb中如何通过Request对象获取客户端IP地址

提供一个获取ip地址的工具类

package com.leo.util;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
/**
 * @ClassName: HttpUtil
 * @Description: 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址;
 * @Author: leo825
 * @Date: 2020-06-04 23:02
 * @Version: 1.0
 */
public class HttpUtil {
    //日志文件
    private static final Logger logger = LogManager.getLogger();
    //获取真实IP地址
    public final static String getIpAddr(HttpServletRequest request) throws IOException {
        // 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址
        String ip = request.getHeader("X-Forwarded-For");
        if (logger.isInfoEnabled()) {
            logger.info("X-Forwarded-For - String ip=" + ip);
        }
        //如果以上获取的的ip是空的或者是unknown
        if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
                if (logger.isInfoEnabled()) {
                    logger.info("Proxy-Client-IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
                if (logger.isInfoEnabled()) {
                    logger.info("WL-Proxy-Client-IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
                if (logger.isInfoEnabled()) {
                    logger.info("HTTP_CLIENT_IP - String ip=" + ip);
                }
            }
            if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
                if (logger.isInfoEnabled()) {
                    logger.info("HTTP_X_FORWARDED_FOR - String ip=" + ip);
                }
            }
            if (ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
                if (logger.isInfoEnabled()) {
                    logger.info("getRemoteAddr - String ip=" + ip);
                }
            }
        } else if (ip.trim().length() > 15) {
            //如果获取到多个IP
            String[] ips = ip.split(",");
            for (int index = 0; index < ips.length; index++) {
                String strIp = ips[index];
                if (ip != null && ip.trim().length() != 0 && !("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }
}