最近我们发现各大社交平台都出现了一个新的功能：IP属地。
比如某乎：
这个IP属地是怎么做到的呢？今天我来教教你，保证你看完直呼Easy~
技术栈
1.Java网络编程
2.Servlet
具体实现
1.获取IP地址及其归属地工具类
package com.mmg.controller;import javax.servlet.http.HttpServletRequest;import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import .HttpURLConnection;import .URL;/*** 获取IP地址工具类*/public class Iputil {/*** 1.通过request对象获取IP* 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址* 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 (ip == null || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("Proxy-Client-IP");}if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("WL-Proxy-Client-IP");}if (ip == null || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("HTTP_CLIENT_IP");}if (ip == null || "unknown".equalsIgnoreCase(ip)) {ip = request.getHeader("HTTP_X_FORWARDED_FOR");}if (ip == null || "unknown".equalsIgnoreCase(ip)) {ip = request.getRemoteAddr();}} catch (Exception e) {e.printStackTrace();}//使用代理，则获取第一个IP地址if (ip == null) {if (ip.indexOf(",") > 0) {ip = ip.substring(0, ip.indexOf(","));}}return ip;}/*** 2.通过调用接口的方式获取IP*/public static String getIp() {try {URL realUrl = new URL("/ipJson.jsp");HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();conn.setRequestMethod("GET");conn.setUseCaches(false);conn.setReadTimeout(6000);conn.setConnectTimeout(6000);conn.setInstanceFollowRedirects(false);int code = conn.getResponseCode();StringBuilder sb = new StringBuilder();String ip = "";if (code == 200) {InputStream in = conn.getInputStream();BufferedReader reader = new BufferedReader(new InputStreamReader(in));String line;while ((line = reader.readLine()) != null) {sb.append(line);}ip = sb.substring(sb.indexOf("ip") + 5, sb.indexOf("pro") - 3);}return ip;} catch (Exception e) {e.printStackTrace();return null;}}/*** 3.通过调用接口根据ip获取归属地*/public static String getAddress(String ip) {try {URL realUrl = new URL("/ipJson.jsp?ip=" + ip + "&json=true");HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();conn.setRequestMethod("GET");conn.setUseCaches(false);conn.setReadTimeout(6000);conn.setConnectTimeout(6000);conn.setInstanceFollowRedirects(false);int code = conn.getResponseCode();StringBuilder sb = new StringBuilder();String ipaddr = "";if (code == 200) {InputStream in = conn.getInputStream();BufferedReader reader = new BufferedReader(new InputStreamReader(in));String line;while ((line = reader.readLine()) != null) {sb.append(line);}ipaddr = ip + "=" + sb.substring(sb.indexOf("addr") + 7, sb.indexOf("regionNames") - 3);}return ipaddr;} catch (Exception e) {e.printStackTrace();return null;}}}
2.测试类
package com.mmg.controller;/*** 测试类*/public class Test {public static void main(String[] args) {System.out.println(Iputil.getIpAddr());System.out.println(Iputil.getAddress(Iputil.getIp()));}}
通过运行这个方法，可以看到，控制台打印了IP和城市信息，也就是我们想要的IP属地信息啦！
在你的项目里，你可以在登录的时候记录当前登录用户的IP和登录地点，也可以在用户发表文章和评论的时候显示出他的IP属地，非常实用哦~
