最近在做一个互联网项目，不可避免和其他互联网项目一样，需要各种类似的功能。其中一个就是通过用户访问网站的IP地址显示当前用户所在地。在没有查阅资料之前，我第一个想到的是应该有这样的RESTFUL服务，可能会有免费的，也有可能会是收费的。后来查阅了相关资料和咨询了客服人员发现了一款相当不错的库：GEOIP。

首先来个Java 版本：

[java]
import java.net.MalformedURLException;
import java.net.URL;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class OmniReader {
public static void main(String[] args) throws Exception {
String license_key = "YOUR_LICENSE_KEY";
String ip_address = "24.24.24.24";

String url_str = "http://geoip.maxmind.com/e l=" + license_key + "&i=" + ip_address;

URL url = new URL(url_str);
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String inLine;

while ((inLine = in.readLine()) != null) {
// Alternatively use a CSV parser here.
Pattern p = Pattern.compile("\"([^\"]*)\"|( <=,|^)([^,]*)( :,|$)");
Matcher m = p.matcher(inLine);

ArrayList fields = new ArrayList();
String f;
while (m.find()) {
f = m.group(1);
if (f!=null) {
fields.add(f);
}
else {
fields.add(m.group(2));
}
}

String countrycode = fields.get(0);
String countryname = fields.get(1);
String regioncode = fields.get(2);
String regionname = fields.get(3);
String city = fields.get(4);
String lat = fields.get(5);
String lon = fields.get(6);
String metrocode = fields.get(7);
String areacode = fields.get(8);
String timezone = fields.get(9);
String continent = fields.get(10);
String postalcode = fields.get(11);
String isp = fields.get(12);
String org = fields.get(13);
String domain = fields.get(14);
String asnum = fields.get(15);
String netspeed = fields.get(16);
String usertype = fields.get(17);
String accuracyradius = fields.get(18);
String countryconf = fields.get(19);
String cityconf = fields.get(20);
String regionconf = fields.get(21);
String postalconf = fields.get(22);
String error = fields.get(23);
}

in.close();
}
}

import java.net.MalformedURLException;
import java.net.URL;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class OmniReader {
public static void main(String[] args) throws Exception {
String license_key = "YOUR_LICENSE_KEY";
String ip_address = "24.24.24.24";

String url_str = "http://geoip.maxmind.com/e l=" + license_key + "&i=" + ip_address;

URL url = new URL(url_str);
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String inLine;

while ((inLine = in.readLine()) != null) {
// Alternatively use a CSV parser here.
Pattern p = Pattern.compile("\"([^\"]*)\"|( <=,|^)([^,]*)( :,|$)");
Matcher m = p.matcher(inLine);

ArrayList fields = new ArrayList();
String f;
while (m.find()) {
f = m.group(1);
if (f!=null) {
fields.add(f);
}
else {
fields.add(m.group(2));
}
}

String countrycode = fields.get(0);
String countryname = fields.get(1);
String regioncode = fields.get(2);
String regionname = fields.get(3);
String city = fields.get(4);
String lat = fields.get(5);
String lon = fields.get(6);
String metrocode = fields.get(7);
String areacode = fields.get(8);
String timezone = fields.get(9);
String continent = fields.get(10);
String postalcode = fields.get(11);
String isp = fields.get(12);
String org = fields.get(13);
String domain = fields.get(14);
String asnum = fields.get(15);
String netspeed = fields.get(16);
String usertype = fields.get(17);
String accuracyradius = fields.get(18);
String countryconf = fields.get(19);
String cityconf = fields.get(20);
String regionconf = fields.get(21);
String postalconf = fields.get(22);
String error = fields.get(23);
}

in.close();
}
}
C#版本：

[csharp]
private string GetMaxMindOmniData(string IP) {
System.Uri objUrl = new System.Uri("http://geoip.maxmind.com/e l=YOUR_LICENSE_KEY&i=" + IP);
System.Net.WebRequest objWebReq;
System.Net.WebResponse objResp;
System.IO.StreamReader sReader;
string strReturn = string.Empty;

try
{
objWebReq = System.Net.WebRequest.Create(objUrl);
objResp = objWebReq.GetResponse();

sReader = new System.IO.StreamReader(objResp.GetResponseStream());
strReturn = sReader.ReadToEnd();

sReader.Close();
objResp.Close();
}
catch (Exception ex)
{
}
finally
{
objWebReq = null;
}

return strReturn;
}

private string GetMaxMindOmniData(string IP) {
System.Uri objUrl = new System.Uri("http://geoip.maxmind.com/e l=YOUR_LICENSE_KEY&i=" + IP);
System.Net.WebRequest objWebReq;
System.Net.WebResponse objResp;
System.IO.StreamReader sReader;
string strReturn = string.Empty;

try
{
objWebReq = System.Net.WebRequest.Create(objUrl);
objResp = objWebReq.GetResponse();

sReader = new System.IO.StreamReader(objResp.GetResponseStream());
strReturn = sReader.ReadToEnd();

sReader.Close();
objResp.Close();
}
catch (Exception ex)
{
}
finally
{
objWebReq = null;
}

return strReturn;
}
Ruby版本：