JAVA获取公网ip

 1 package 动态ip发布;
 2 
 3 import java.io.BufferedReader;
 4 import java.io.FileWriter;
 5 import java.io.IOException;
 6 import java.io.InputStreamReader;
 7 import java.io.PrintWriter;
 8 import java.net.MalformedURLException;
 9 import java.net.URL;
10 import java.net.URLConnection;
11 
12 public class Main {
13     public static void main(String args[]) {
14         System.out.println(getip.publicip());
15     }
16 }
17 class getip {
18     public static String publicip() {
19         URL url = null;
20         URLConnection urlconn = null;
21         BufferedReader br = null;
22         try {
23             url = new URL("http://2017.ip138.com/ic.asp");//爬取的网站是百度搜索ip时排名第一的那个
24             urlconn = url.openConnection();
25             br = new BufferedReader(new InputStreamReader(
26                     urlconn.getInputStream()));
27             String buf = null;
28             String get= null;
29             while ((buf = br.readLine()) != null) {
30                 get+=buf;
31             }
32             int where,end;
33             for(where=0;where<get.length()&&get.charAt(where)!=‘[‘;where++);
34             for(end=where;end<get.length()&&get.charAt(end)!=‘]‘;end++);
35             get=get.substring(where+1,end);
36             return get;
37         } catch (MalformedURLException e) {
38             e.printStackTrace();
39         } catch (IOException e) {
40             e.printStackTrace();
41         } finally {
42             try {
43                 br.close();
44             } catch (IOException e) {
45                 e.printStackTrace();
46             }
47         }
48         return null;
49     }
50 }