Java 开发常用代码块之一

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网络编程

获取 IP 地址

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import cn.hutool.core.util.StrUtil;
import javax.servlet.http.HttpServletRequest;

/**
 * IP地址工具
 */
public class IPUtils {

    /**
     * 获取IP地址
     * 如果使用Nginx等反向代理软件，不能通过request.getRemoteAddr()获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = null;
        try {
            ip = request.getHeader("x-forwarded-for");
            if (StrUtil.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (StrUtil.isEmpty(ip) || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (StrUtil.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (StrUtil.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (StrUtil.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
        } catch (Exception e) {
            System.out.println("IPUtils ERROR " + e.getLocalizedMessage());
        }
        return ip;
    }

}

正则表达式解析 URL

通过正则表达式，获取 URL 中的协议、域名、端口、URI。

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import cn.hutool.core.util.StrUtil;

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class HttpUtil {

    public static final String HTTP_PROTOCOL = "http://";

    public static final String HTTPS_PROTOCOL = "https://";

    /**
     * 解析URL（包括协议、域名、端口、URI）
     *
     * @param url
     * @return
     */
    public static Map<String, String> parseUrl(String url) {
        Map<String, String> map = new HashMap(4);
        try {
            Pattern pattern = Pattern.compile("(https?://)([^:^/]*)(:\\d*)?(.*)?");
            Matcher matcher = pattern.matcher(url);
            boolean findResult = matcher.find();
            if (!findResult) {
                return map;
            }

            String protocol = matcher.group(1);
            String domain = matcher.group(2);
            String port = matcher.group(3);
            String uri = matcher.group(4);

            if (StrUtil.isBlank(port)) {
                if (HTTP_PROTOCOL.equals(protocol)) {
                    port = "80";
                } else if (HTTPS_PROTOCOL.equals(protocol)) {
                    port = "443";
                } else {
                    port = "unknown";
                }
            } else {
                port = port.replace(":", "");
            }

            map.put("protocol", protocol);
            map.put("domain", domain);
            map.put("port", port);
            map.put("uri", uri);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return map;
    }

}