根据百度API获得经纬度，然后根据经纬度在获得城市信息

项目中使用到的知识点，已被将来使用

1.根据地址查询经纬度

public static Map<String, Object> getCoordinate(String addr) throws IOException { 

String address = null; 
Map<String, Object> map = new HashMap<String, Object>(); 
try { 
address = java.net.URLEncoder.encode(addr, "UTF-8"); 
} catch (UnsupportedEncodingException e1) { 
e1.printStackTrace(); 
} 
String key = "DVa8ozBaZiDiCghUlOaVGh0fuly5CvdZ"; 
String url = String.format("http://api.map.baidu.com/geocoder/v2/?address=%s&output=json&ak=%s", address, key);
URL myURL = null; 
URLConnection httpsConn = null; 
try { 
myURL = new URL(url); 
} catch (MalformedURLException e) { 
e.printStackTrace(); 
} 
InputStreamReader insr = null;
BufferedReader br = null;
try { 
httpsConn = (URLConnection) myURL.openConnection();// 不使用代理 
if (httpsConn != null) { 
insr = new InputStreamReader( 
httpsConn.getInputStream(), "UTF-8"); 
br = new BufferedReader(insr); 
String data = null; 
String lng = "";
String lat = "";

while((data= br.readLine())!=null){ 
JSONObject para = JSONObject.parseObject(data);
if(para!=null){
String result = para.getString("result");
JSONObject paras = JSONObject.parseObject(result);
if(paras!=null){
String location = paras.getString("location");
JSONObject parasl = JSONObject.parseObject(location);
if(parasl!=null){
lng = parasl.getString("lng");
lat = parasl.getString("lat");
}
}
}
}
map.put("lat", lat);
map.put("lng", lng);
} 
} catch (IOException e) { 
e.printStackTrace(); 
} finally {
if(insr!=null){
insr.close();
}
if(br!=null){
br.close();
}
}
return map; 

} 

2.根据经纬度查询城市

public Map<String, Object> getCity(String lngs,String lats) throws IOException { 
String lng = null; 
String lat = null; 
Map<String, Object> map = new HashMap<String, Object>(); 
try { 
lat = java.net.URLEncoder.encode(lats, "UTF-8"); 
lng = java.net.URLEncoder.encode(lngs, "UTF-8"); 
} catch (UnsupportedEncodingException e1) { 
e1.printStackTrace(); 
} 
String lngAndlat = lat+","+lng;
String key = "DVa8ozBaZiDiCghUlOaVGh0fuly5CvdZ"; 
String url = String.format("http://api.map.baidu.com/geocoder/v2/?ak=%s&location=%s&output=json&pois=1", key ,lngAndlat);
URL myURL = null; 
URLConnection httpsConn = null; 
try { 
myURL = new URL(url); 
} catch (MalformedURLException e) { 
e.printStackTrace(); 
} 
InputStreamReader insr = null;
BufferedReader br = null;
try { 
httpsConn = (URLConnection) myURL.openConnection();// 不使用代理 
if (httpsConn != null) { 
insr = new InputStreamReader( 
httpsConn.getInputStream(), "UTF-8"); 
br = new BufferedReader(insr); 
String data = null; 
String city = "";

while((data= br.readLine())!=null){ 
JSONObject para = JSONObject.parseObject(data);
if(para!=null){
String result = para.getString("result");
JSONObject paras = JSONObject.parseObject(result);
if(paras!=null){
String addressComponent = paras.getString("addressComponent");
JSONObject parasl = JSONObject.parseObject(addressComponent);
if(parasl!=null){
city = parasl.getString("city");
}
}
}
}
map.put("city", city);
} 
} catch (IOException e) { 
e.printStackTrace(); 
} finally {
if(insr!=null){
insr.close();
}
if(br!=null){
br.close();
}
}
return map; 
}