微信公众平台开发（三）--位置信息的识别

位置识别这是实际应用经常应用的消息，特别是很多商家，通过了解用户位置，给用户提供特别的产品或是商场的推荐。其中用户可能发送两种类型的消息：

1.微信地理位置信息

2.路名、标志性建筑或是商场名称

1.微信地理位置消息

认识一下，微信地理位置消息，包含一些什么信息

 

< xml >
< ToUserName > <![CDATA[ toUser ]]> </ ToUserName >
< FromUserName > <![CDATA[ fromUser ]]> </ FromUserName >
< CreateTime > 1351776360 </ CreateTime >
< MsgType > <![CDATA[ location ]]> </ MsgType >
< Location_X > 23.134521 </ Location_X >
< Location_Y > 113.358803 </ Location_Y >
< Scale > 20 </ Scale >
< Label > <![CDATA[ 位置信息 ]]> </ Label >
< MsgId > 1234567890123456 </ MsgId >
</ xml >

包含的主要信息有经度纬度和Label的位置。可以根据label中描述的位置信息，提供给用户对应的服务。也可根据用户的经度纬度信息，提供你最近的产品或是有地域性的产品。

首先根据微信的地理位置信息，定义WeChatLocationMessage类，并能把Xml转换为WeChatLocationMessage对象

 

public   class  WeChatLocationMessage {
     private  String toUserName;
     private  String fromUserName;
     private  String createTime;
     private  String msgType;
     private  String locationx;
     private  String localtiony;
     private  String scale;
     private  String label;
     private  String msgId;
    
     public   static  WeChatLocationMessage getWeChatLocationMessage(String xml){
        XStream xstream  =   new  XStream( new  DomDriver());
        WeChatLocationMessage  message  =   null ;
        xstream.alias( " xml " , WeChatLocationMessage. class );
        xstream.aliasField( " ToUserName " , WeChatLocationMessage. class ,  " toUserName " );
        xstream.aliasField( " FromUserName " , WeChatLocationMessage. class ,  " fromUserName " );
        xstream.aliasField( " CreateTime " , WeChatLocationMessage. class ,  " createTime " );
        xstream.aliasField( " MsgType " , WeChatLocationMessage. class ,  " msgType " );
        xstream.aliasField( " Location_X " , WeChatLocationMessage. class ,  " locationx " );
        xstream.aliasField( " Location_Y " , WeChatLocationMessage. class ,  " localtiony " );
        xstream.aliasField( " Scale " , WeChatLocationMessage. class ,  " scale " );
        xstream.aliasField( " Label " , WeChatLocationMessage. class ,  " label " );
        xstream.aliasField( " MsgId " , WeChatLocationMessage. class ,  " msgId " );
        message  =  (WeChatLocationMessage)xstream.fromXML(xml);
         return  message;
    }
// getter and setter
}

本文利用百度的地图API，查找最近的银行做为示例。

 

     public  String getPalace(String query,String lat,String lng)  throws  ClientProtocolException, IOException{
        HttpClient httpClient  =   new  DefaultHttpClient();
        String url  =  palceRequestUrl(query,lat,lng);
        logger.log(Level.INFO, url);
        HttpGet httpget  =   new  HttpGet(url);
        ResponseHandler < String >  responseHandler  =   new  BasicResponseHandler();
        String responseBody  =  httpClient.execute(httpget, responseHandler);
        logger.log(Level.INFO, " baidu response: " + responseBody);
         return  responseBody;
    }
    
     public  String palceRequestUrl(String query,String lat,String lng)  throws  UnsupportedEncodingException {
        String url  =  WeChatConstant.BASEURL  +   " place/search?query= "   +  URLEncoder.encode(query, " UTF-8 " )  +   " &key= "
                 +  WeChatConstant.MAPKEY  + " &location= " + lat + " , " + lng  + " &radius=2000 " + " &output= "   +  WeChatConstant.OUTPUTFORMAT;
         return  url;
    }

输出的结果

< PlaceSearchResponse >
     < status > OK </ status >
     < results >
         < result >
             < name > 中国工商银行东长安街支行 </ name >
             < location >
                 < lat > 39.915891 </ lat >
                 < lng > 116.41867 </ lng >
             </ location >
             < address > 东城区东长安街1号东方广场西三办公楼1楼 </ address >
             < uid > a025683c73033c35a21de987 </ uid >
             < detail_url > http: // api.map.baidu.com/place/detail?uid=a025683c73033c35a21de987&amp;amp;output=html&amp;amp;source=placeapi
             </ detail_url >
             < tag > 银行,王府井 / 东单 </ tag >

         </ result >
       </ results >
</ PlaceSearchResponse >

 

接下来，把百度地图反映出来的最近位置信息，以图文消息的格式展示给微信用户

 

     public   static  String getWeChatReplyNewsMessageByBaiduPlace(List < BaiduPlaceResponse >  placeList,  double  lat,  double  lng,String userName,  int  size){
        WeChatReplyNewsMessage newsMessage  =   new  WeChatReplyNewsMessage();
        List < Item >  items  =   new  ArrayList < Item > ();
        StringBuffer strBuf  =   new  StringBuffer();
        logger.log(Level.INFO, " placeList count= " + placeList.size());
        newsMessage.setItems(items);
         if (placeList.size() > size){
            newsMessage.setArticleCount(size);
        }
         else {
            newsMessage.setArticleCount(placeList.size());
        }
        logger.log(Level.INFO, " article count= " + newsMessage.getArticleCount());
        newsMessage.setCreateTime( new  Date().getTime() + "" );
        newsMessage.setMsgType( " news " );
        newsMessage.setFuncFlag( " 0 " );
        newsMessage.setToUserName(userName);
        newsMessage.setFromUserName(WeChatConstant.FROMUSERNAME);
         for ( int  i  =   0 ;i  < newsMessage.getArticleCount();i ++ ){
            BaiduPlaceResponse place  =  placeList.get(i);
            Double distance  =  GeoUtil.DistanceOfTwoPoints(Double.valueOf(place.getLng()), Double.valueOf(place.getLat()), lng, lat, GaussSphere.Beijing54);
            Item item  =   new  Item();
            item.setTitle(place.getName() + " [ " + distance + " 米] " + " \n " + place.getAddress() + " \n " + place.getTelephone());
            item.setPicUrl( "" );
            item.setUrl(place.getDetailUrl());
            item.setDescription( "" );
            items.add(item);
        }
        logger.log(Level.INFO, " newMessage= " + newsMessage.toString());
        strBuf  =  strBuf.append(getWeChatNewsMessage(newsMessage));
        
         return  strBuf.toString();
    }
    
     public   static  String getWeChatNewsMessage(WeChatReplyNewsMessage newsMessage){
        XStream xstream  =   new  XStream( new  DomDriver());
        xstream.alias( " xml " , WeChatReplyNewsMessage. class );
        xstream.aliasField( " ToUserName " , WeChatReplyNewsMessage. class ,  " toUserName " );
        xstream.aliasField( " FromUserName " , WeChatReplyNewsMessage. class ,  " fromUserName " );
        xstream.aliasField( " CreateTime " , WeChatReplyNewsMessage. class ,  " createTime " );
        xstream.aliasField( " MsgType " , WeChatReplyNewsMessage. class ,  " msgType " );
        xstream.aliasField( " ArticleCount " , WeChatReplyNewsMessage. class ,  " articleCount " );
        xstream.aliasField( " Content " , WeChatReplyNewsMessage. class ,  " content " );
        xstream.aliasField( " FuncFlag " , WeChatReplyNewsMessage. class ,  " funcFlag " );
        xstream.aliasField( " Articles " , WeChatReplyNewsMessage. class ,  " items " );
        
        xstream.alias( " item " , Item. class );
        xstream.aliasField( " Title " , Item. class ,  " title " );
        xstream.aliasField( " Description " , Item. class ,  " description " );
        xstream.aliasField( " PicUrl " , Item. class ,  " picUrl " );
        xstream.aliasField( " Url " , Item. class ,  " url " );
        
         return  xstream.toXML(newsMessage);
    }

 

2.路名、标志性建筑或是商场名称

对路名、标志性建筑等信息，方法还是通过第三方地图信息，确定输入的位置信息的经度纬度。

本文使用百度地图API，确定所查找的位置的经度和纬度。

 

     public  String getGeoCode(String query)  throws  ClientProtocolException, IOException{
        HttpClient httpClient  =   new  DefaultHttpClient();
        String url  =  geoCodeRequestUrl(query);
        logger.log(Level.INFO, url);
        HttpGet httpget  =   new  HttpGet(url);
        ResponseHandler < String >  responseHandler  =   new  BasicResponseHandler();
        String responseBody  =  httpClient.execute(httpget, responseHandler);
        logger.log(Level.INFO, " baidu response: " + responseBody);
         return  responseBody;
    }
    
     public  String geoCodeRequestUrl(String query)  throws  UnsupportedEncodingException{
        String url  =  WeChatConstant.BASEURL  +   " geocoder?address= "   +  URLEncoder.encode(query, " UTF-8 " )  +   " &key= "
                 +  WeChatConstant.MAPKEY  +   " &output= "   +  WeChatConstant.OUTPUTFORMAT;
         return  url;
    }

 

确定了经度和纬度，问题就变成和第1种消息类型一致了，根据经度纬度去做相应处理。

3.源代码

本文的代码较长，提供源代码下载。

WeChatDemo下载

 

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