XML&&JSON
引言NOKIA 有句著名的广告语：“科技以人为本”。任何技术都是为了满足人的生产生活需要而产生的。具体到小小的一个手机，里面蕴含的技术也是浩如烟海，是几千年来人类科技的结晶，单个人穷其一生也未必能掌握其一角。不过个人一直认为基本的技术和思想是放之四海而皆准的，许多技术未必需要我们从头到尾再研究一遍，我们要做的就是站在巨人的肩膀上，利用其成果来为人们的需求服务。 XMLXML即可扩展标记语言(eXtensible Markup Language)。标记是指计算机所能理解的信息符号，通过此种标记，计算机之间可以处理包含各种信息的文章等。如何定义这些标记，既可以选择国际通用的标记语言，比如HTML，也可以使用象XML这样由相关人士自由决定的标记语言，这就是语言的可扩展性。XML是从SGML中简化修改出来的。它主要用到的有XML、XSL和XPath等。 <note>
<to>George</to>
<from>John</from>
<heading>Reminder</heading>
<body>Don't forget the meeting!</body>
</note>
上面的这条便签具有自我描述性。它拥有标题以及留言，同时包含了发送者和接受者的信息。但是，这个 XML 文档仍然没有做任何事情。它仅仅是包装在XML标签中的纯粹的信息。我们需要编写软件或者程序，才能传送、接收和显示出这个文档。 XML如何解析？step1：XML文件是一棵树，首先需要找到对应的节点，然后从节点开始解析，比如搜索找到的就是result/weights/weight 和result/weights/weight 2个节点，分别从这个开始解析： public ResultInfo onParser(Element rootElement) {
int resp = -1;
try {
String elName = "header/respcode";
resp = Integer.parseInt(selectNodeString(rootElement,elName));
} catch (NumberFormatException e) {
e.printStackTrace();
}
Log.d(TAG,"resp= " + resp);
if (resp != 0) {
return null;
}
ResultInfo searchResultInfo = new ResultInfo();
// Parse Search Weight
@SuppressWarnings("rawtypes")
final List weights = rootElement.selectNodes(rootElement.getPath() + "/"
+ "result/weights/weight");
ResultInfo[] resultFilterInfos = parseVideos(weights);
if (resultFilterInfos != null) {
ResultInfo weight = new ResultInfo();
weight.putResultInfoArray(ResultInfo.KEY_VIDEOS,resultFilterInfos);
searchResultInfo.putResultInfo(ResultInfo.KEY_WEIGHT,weight);
}
// Parse Albums
@SuppressWarnings("rawtypes")
final List albums = rootElement.selectNodes(rootElement.getPath() + "/"
+ "result/albums/album");
ResultInfo[] resultInfos = parseVideos(albums);
if (resultInfos != null) {
ResultInfo album = new ResultInfo();
album.putResultInfoArray(ResultInfo.KEY_VIDEOS,resultInfos);
searchResultInfo.putResultInfo(ResultInfo.KEY_SEARCH,album);
}
return searchResultInfo;
}
step2找到了对应的Node，即从对应的Node开始递归的查找，直到找到最小的节点，也就是最基本的单元Element。再对每一个Element进行解析： private ResultInfo[] parseVideos(final List nodes) {
if (nodes != null && nodes.size() > 0) {
final int size = nodes.size();
final ResultInfo[] vis = new ResultInfo[size];
int i = 0;
for (Object o : nodes) {
if (o instanceof Element) {
final Element videoElement = (Element) o;
ResultInfo vi = parseVideo(videoElement);
vis[i] = vi;
}
i++;
}
return vis;
}
return null;
}
step3针对获取到的Element，解析出对应的String将数据传递给VideoInfo这个类： private ResultInfo parseVideo(final Element videoElement) {
final String id = videoElement.elementText("album_id");
final String title = videoElement.elementText("title");
final String categoryId = videoElement.elementText("category_id");
final String categoryName = videoElement.elementText("category_name");
final String count = videoElement.elementText("count");
final String imgUrl = videoElement.elementText("img180236");
final String duration = videoElement.elementText("duration");
final String mainactors = videoElement.elementText("mainactors");
final String sitename = videoElement.elementText("site_name");
final String videourl = videoElement.elementText("vedio_url");
final String sort = videoElement.elementText("sort");
final String tv_id = videoElement.elementText("tv_id");
ResultInfo vi = new ResultInfo();
vi.putString(VideoInfo.ID,id);
vi.putString(VideoInfo.TITLE,title);
vi.putString(VideoInfo.CATEGORY_ID,categoryId);
vi.putString(VideoInfo.CATEGORY_NAME,categoryName);
vi.putString(VideoInfo.COUNT,count);
vi.putString(VideoInfo.IMG_URL,imgUrl);
vi.putString(VideoInfo.DURATION,duration);
vi.putString(VideoInfo.MAINACTORS,mainactors);
vi.putString(VideoInfo.SITENAME,sitename);
vi.putString(VideoInfo.VIDEOURL,videourl);
vi.putString(VideoInfo.SORT,sort);
vi.putString(VideoInfo.TV_ID,tv_id);
return vi;
}
step4当使用XML解析器将XML数据解析出来之后。需要将这些数据提取出来，也是通过连续2层提取，将数据定位到每个video， 将每个video里的数据传递给SearchVideoInfo这个ArrayList，然后将ArrayList中的数据和对应的Adapter数据关联起来： public static ArrayList<SearchVideoInfo> getSearchVideoInfo(ResultInfo searchResultInfo) {
ResultInfo resultInfo = null;
ResultInfo[] videos = null;
ArrayList<SearchVideoInfo> searchVideoInfos = null;
if (searchResultInfo != null) {
resultInfo = searchResultInfo.getResultInfo(ResultInfo.KEY_SEARCH);
}
if (resultInfo != null) {
videos = resultInfo.getResultInfoArray(ResultInfo.KEY_VIDEOS);
}
if (videos != null && videos.length > 0) {
searchVideoInfos = new ArrayList<SearchVideoInfo>(videos.length);
for (ResultInfo video : videos) {
SearchVideoInfo searchInfo = new SearchVideoInfo();
searchInfo.setAlbum_id(video.getString(VideoInfo.ID));
searchInfo.setTitle(video.getString(VideoInfo.TITLE));
searchInfo.setChannel_id(video.getString(VideoInfo.CATEGORY_ID));
searchInfo.setImgUrl(video.getString(VideoInfo.IMG_URL));
searchInfo.setDuration(video.getString(VideoInfo.DURATION));
searchInfo.setMainActors(video.getString(VideoInfo.MAINACTORS));
searchInfo.setSiteName(video.getString(VideoInfo.SITENAME));
searchInfo.setVideo_url(video.getString(VideoInfo.VIDEOURL));
searchInfo.setOrder(video.getString(VideoInfo.SORT));
searchInfo.setTv_id(video.getString(VideoInfo.TV_ID));
// searchInfo.setContinueType(video.getString(VideoInfo.CONTINUETYPE));
searchVideoInfos.add(searchInfo);
}
}
if (searchVideoInfos == null) {
MyLog.e(TAG,"error,getSearchVideoInfo,can not get info");
}
return searchVideoInfos;
}
JSON定义：JSON：JavaScript对象表示法(JavaScript Object Notation）,是一种轻量级的数据交换格式,易于人阅读和编写,同时也易于机器解析和生成。 "code": 1,"data": 0,"albumIdList": [
{
"totalidnum": 2000,"idlist": [
"319281600"
]
}
],"albumArray": {
"319281600": {
"_as": "","_blk": 0,"_cid": 1,"_ct": "2014-10-10 17:55:06","_da": "","_dl": 0,"_dn": "7296","_id": 319281600,"_img": "http://pic2.qiyipic.com/image/20141016/19/ca/v_108628048_m_601_m1_120_160.jpg","_ip": 1,"_ma": "","_pc": 2,"_pid": 0,"_reseftv": 959,"_t": "末代独裁","_tvct": 1,"_tvs": 1,"_vt": 0,"a_av": 1,"a_pro": "","bpt": "0","clm": "","cn_year": "0","co_album_id": "0","ctype": 0,"desc": "","down": 0,"down2": "0","drm": 0,"fst_time": "2014-10-16","h1_img": "http://pic2.qiyipic.com/image/20141016/19/ca/v_108628048_m_601_m1_180_236.jpg","h2_img": "http://pic2.qiyipic.com/image/20141016/19/ca/v_108628048_m_601_m1_195_260.jpg","is_h": 0,"is_n": 0,"is_zb": 0,"k_word": "","language": 0,"live_center": 0,"live_start_time": 0,"live_stop_time": 0,"logo": 1,"m_av": 1,"p_av": 1,"p_s": 0,"p_s_1": 0,"p_s_4": 0,"p_s_8": 0,"qiyi_pro": 0,"qiyi_year": "0","qt_id": "1005722","s_TT": "","songname": "","t_pc": 1,"tag": "当代 美国 乡村 大片","tv_eftv": 1,"tv_pha": "","tv_pro": "","tv_ss": "","tvfcs": "雄心壮志背后的真相","up": 0,"up2": "0","upcl": "","v2_img": "http://pic2.qiyipic.com/image/20141016/19/ca/v_108628048_m_601_m1_284_160.jpg","v3_img": "http://pic2.qiyipic.com/image/20141016/19/ca/v_108628048_m_601_m1_480_270.jpg","vv": "1","year": "2007","tv_id": "0","vv_p": 0,"vv_f": 2,"vv_m": 0,"_sc": 8
}
},"changeAlbum": null,"category": null,"before": "2~4~1~7~3","latest_push_id": "655","up_tm": "1413441370874","recommend_attach": "","preset_keys": null,"category_group": null,"exp_ts": 120,"stfile_path": "/data/view/online5/0/1/2.1.8.5.1.txt"
}
从上面的例子可以很清晰的看出JSON是如何展示一个电影的数据的，当然这是JSON格式化之后的数据。JSON的元数据是不便于阅读的。 解析JSON下面以视频中解析iQiyi的每个视频album数据为例来说明如何解析JSON： JsonObjectRequest jsonObjRequest = new JsonObjectRequest(Request.Method.GET,url,null,new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
MyLog.d(TAG,"response=" + response);
parseiQiyiInterfaceResponse(response);
} catch (Exception e) {
e.printStackTrace();
}
}
},new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
/*
* if (error instanceof NetworkError) { } else if (error
* instanceof ClientError) { } else if (error instanceof
* ServerError) { } else if (error instanceof
* AuthFailureError) { } else if (error instanceof
* ParseError) { } else if (error instanceof
* NoConnectionError) { } else if (error instanceof
* TimeoutError) { }
*/
MyLog.e(TAG,"onErrorResponse,error=" + error);
}
}) {
@Override
public Map<String,String> getHeaders() throws AuthFailureError {
HashMap<String,String> headers = new HashMap<String,String>();
headers.put("t",iQiyiInterface.getEncryptTimestamp());
headers.put("sign",iQiyiInterface.getSign());
return headers;
}
};
第二步，获取到对应的对应的JSONObject数据： public void getJsonObjectString(String url) {
mQueue = VideoApplication.getInstance().getRequestQueue();
JsonObjectRequest jsObjRequest = new JsonObjectRequest(Request.Method.GET,null,new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
MyLog.e(TAG,"response = " + response.toString());
JSONArray jsonArray = null;
JSONObject jsonObject = null;
try {
jsonObject = response.getJSONObject("response");
jsonArray = jsonObject.getJSONObject("result").getJSONArray("album");
} catch (JSONException e) {
e.printStackTrace();
}
if (jsonArray == null) {
return;
}
mChannelList = VideoUtils.parseVideoJsonArray(jsonArray);
if (isLoading) {
isLoading = false;
if (mIsGrid) {
mChannelGridAdapter.appendChannelVideoInfo(mChannelList);
} else {
mChannelListAdapter.appendChannelVideoInfo(mChannelList);
}
} else {
if (mIsGrid) {
mChannelGridAdapter.setChannelVideoInfo(mChannelList);
showOppoGrid();
} else {
mChannelListAdapter.setChannelVideoInfo(mChannelList);
showOppoList();
}
}
}
},new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
MyLog.e(TAG,"error = " + error);
}
});
jsObjRequest.setTag(TAG);
jsObjRequest.setShouldCache(true);
mQueue.add(jsObjRequest);
mQueue.start();
}
获取到JSON Object之后，就对这个JSONObject进行解析： private ArrayList<VideoConstant> parseVideoAlbumJsonObject(JSONObject albumJSONObject,ArrayList<Integer> albumIdJSONArrayList) {
MyLog.d(TAG,"parseVideoAlbumJsonObject,length=" + albumJSONObject.length());
if (albumJSONObject.length() < 1) {
return null;
}
ArrayList<VideoConstant> videos = new ArrayList<VideoConstant>();
try {
for (int index = 0; index < albumJSONObject.length(); index++) {
VideoConstant video = new VideoConstant();
JSONObject itemJsonObject;
itemJsonObject = albumJSONObject.getJSONObject(albumIdJSONArrayList.get(index)
.toString());
MyLog.d(TAG,"string=" + albumIdJSONArrayList.get(index).toString());
video.mAlbumId = itemJsonObject.optString(InterfaceParameterName.ID);
video.mAtitle = itemJsonObject.optString(InterfaceParameterName.TITLE);
video.mEpisodeCount = itemJsonObject.optString(InterfaceParameterName.UPDATE_SET);
video.mTvSets = itemJsonObject.optString(InterfaceParameterName.TV_SETS);
video.mDesc = itemJsonObject.optString(InterfaceParameterName.DESCRIPTION);
video.mCid = itemJsonObject.optString(InterfaceParameterName.CATEGORY_ID);
video.mImg = itemJsonObject.optString(InterfaceParameterName.IMG);
video.mHighimg = itemJsonObject
.optString(InterfaceParameterName.HIGH_RESO_PORT_IMG);
video.mHoriImg = itemJsonObject
.optString(InterfaceParameterName.HIGH_RESO_HORI_IMG);
video.mScore = itemJsonObject.optString(InterfaceParameterName.SCORE);
video.mMainActors = itemJsonObject.optString(InterfaceParameterName.MAIN_ACTOR);
video.mCreateTime = itemJsonObject.optString(InterfaceParameterName.CREATE_TIME);
video.mDuration = itemJsonObject.optString(InterfaceParameterName.DURATION);
video.mTag = itemJsonObject.optString(InterfaceParameterName.TAG);
MyLog.d(TAG,"id=" + video.mAlbumId + ",title=" + video.mAlbumTitle + ",img="
+ video.mHighimg + ",tvsets=" + video.mTvSets);
videos.add(video);
}
} catch (JSONException e) {
e.printStackTrace();
}
return videos;
}
<4>. Android JSON解析库 上面介绍都是使用Android提供的原生类解析JSON，最大的好处是项目不需要引入第三方库，但是如果比较注重开发效率而且不在意应用大小增加几百K的话，有以下JSON可供选择： Jackson google-gson Json-lib 大家可以去对应的官网下载并学习:) JSON和XML就像武林界的屠龙刀和倚天剑，那么他们孰强孰弱？ XML长期执数据传输界之牛耳，而JSON作为后起之秀，已经盟主发起了挑战。 那就让他们来进行PK一下： 没有结束标签 更短 读写的速度更快 能够使用内建的 JavaScript eval() 方法进行解析 使用数组 不使用保留字 总之： JSON 比 XML 更小、更快，更易解析。 XML是element、attribute和element content。
JSON的主要组成成分： JSON是object、array、string、number、boolean(true/false)和null。
XML要表示一个object(指name-value pair的集合)，最初可能会使用element作为object，每个key-value pair 用 attribute 表示： <student name="John" age="10"/>
但如个某个 value 也是 object，那么就不可以当作attribute: <student name="John" age="10">
<address>
<country>China</country>
<province>Guang Dong</province>
<city>...</city>
<district>...</district>
...
</address>
</student>
那么，什么时候用element，什么时候用attribute，就已经是一个问题了。 {
"name": "John","age" : 10,"address" : {
"country" : "China","province" : "Guang Dong","city" : "..","district" : "..",...
}
}
One More Thing… JSON与XML相比就是这样的。 四、总结 这篇文章只是对XML和JSON这2种目前主流使用的数据格式进行了解释，并系统的学习了其中的语法及如何进行解析，同时在最好针对XML和JSON做了对比，了解其不同点和各自的优势。 （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |