根据ip地址获取用户所在地

java代码：

package com.henu.controller;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.nio.charset.Charset;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * java根据url获取json对象
 * 
 * @author dxy
 * @since 2017-9-15 需要添加java-json.jar才能运行
 */
public class GetPlaceByIp {

    private static String readAll(Reader rd) throws IOException {
        StringBuilder sb = new StringBuilder();
        int cp;
        while ((cp = rd.read()) != -1) {
            sb.append((char) cp);
        }
        return sb.toString();
    }

    public static JSONObject readJsonFromUrl(String url) throws IOException,
            JSONException {
        InputStream is = new URL(url).openStream();
        try {
            BufferedReader rd = new BufferedReader(new InputStreamReader(is,
                    Charset.forName("UTF-8")));
            String jsonText = readAll(rd);
            JSONObject json = new JSONObject(jsonText);
            return json;
        } finally {
            is.close();
            // System.out.println("同时 从这里也能看出 即便return了，仍然会执行finally的！");
        }
    }

    public static void main(String[] args) throws IOException, JSONException {
        // 这里调用百度的ip定位api服务 详见
        // http://api.map.baidu.com/lbsapi/cloud/ip-location-api.htm
        JSONObject json = readJsonFromUrl("http://api.map.baidu.com/location/ip?ak=F454f8a5efe5e577997931cc01de3974&ip=218.28.192.38");
        System.out.println(json.toString());
        System.out.println(((JSONObject) json.get("content")).get("address"));
    }
}

控制台输出：

{"content":{"point":{"y":"4106269.36","x":"12651558.14"},"address":"河南省郑州市","address_detail":{"street":"","province":"河南省","city_code":268,"street_number":"","district":"","city":"郑州市"}},"status":0,"address":"CN|河南|郑州|None|UNICOM|0|0"}
河南省郑州市