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

原创文章，转载请注明： 转载自http://www.qiyadeng.com/

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