Android网络与数据存储——网络编程数据处理(网络请求解析Json,解析xml)

protocol://host:port/resourceName

https://www.baidu.com

public void requestCityData(final String urlString) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    URL url = new URL(urlString);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(8000);
                    connection.setReadTimeout(8000);
                    connection.connect();
                    if (connection.getResponseCode() == 200) {
                        InputStream inputStream = connection.getInputStream();
                        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                        String line;
                        StringBuilder builder = new StringBuilder();
                        while ((line = reader.readLine()) != null) {
                            builder.append(line);
                        }
                        reader.close();
                        String result = builder.toString();
                        Message msg = new Message();
                        msg.what = 0;
                        msg.obj = result;
                        handler.sendMessage(msg);
                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
}

<uses-permission android:name="android.permission.INTERNET" />

<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id = "0" url = "http://www.baidu.com" >百度</item>
    <item id = "1" url = "http://www.google.com" >谷歌</item>
    <item id = "2" url = "http://www.sohu.com" >搜狐</item>
</web>

public class SAXParseHandler extends DefaultHandler {
    private List<WebURL> mWebURLs;
    private WebURL mWebURL;
    private boolean state = false;
    @Override
    public void startDocument() throws SAXException {
        mWebURLs = new ArrayList<>();
    }
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        mWebURL = new WebURL();
        if (TextUtils.equals(localName, "item")){
            for (int i = 0; i < attributes.getLength(); i++) {
                if (TextUtils.equals(attributes.getLocalName(i), "id")){
                    mWebURL.setmID(Integer.parseInt(attributes.getValue(i)));
                }else if (TextUtils.equals(attributes.getLocalName(i), "url")){
                    mWebURL.setmUrl(attributes.getValue(i));
                }
            }
            state = true;
        }
    }
    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        String content = String.valueOf(ch, start, length);
        if (state) {
            mWebURL.setmContent(content);
            state = false;
        }
    }
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (TextUtils.equals(localName, "item")){
            mWebURLs.add(mWebURL);
        }
    }
    @Override
    public void endDocument() throws SAXException {
    }
}

private void testSAXParse() throws ParserConfigurationException, SAXException, IOException {
        //定义一个factory API，能够配置和获取一个SAX解析器去解析xml
        //SAXParserFactory.newInstance();返回Android的接口SAXParserFactory，不像其他Java接口，该方法不能产生系统属性
        SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();//属性文件或服务API
        //定义一个API包裹XMLReader实现类
        SAXParser saxParser = saxParserFactory.newSAXParser();
        //读一个xml文档的接口，用于回调
        XMLReader xmlReader = saxParser.getXMLReader();
        saxParseHandler = new SAXParseHandler();
        //将saxParseHandler的实例设置到XMLReader中
        xmlReader.setContentHandler(saxParseHandler);
        InputStream inputStream = getResources().openRawResource(R.raw.test);
        InputSource inputSource = new InputSource(inputStream);
        //开始执行解析
        xmlReader.parse(inputSource);
    }

{city_info: [ 
{city: "北京", cnty: "中国", id: "CN101010100", lat: "39.904000", lon: "116.391000", prov: "直辖市" }, ... 
] }

public List<CityInfo> parseCityData(String cityData) {
        List<CityInfo> cityInfos = new ArrayList<>();
        try {
            JSONObject jsonObject = new JSONObject(cityData);
            JSONArray jsonArray = jsonObject.getJSONArray("city_info");
            for (int i = 0; i < jsonArray.length(); i++) {
                JSONObject cityObject = (JSONObject) jsonArray.get(i);
                String city = cityObject.getString("city");
                String prov = cityObject.getString("prov");
                CityInfo cityInfo = new CityInfo(city, prov);
                cityInfos.add(cityInfo);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return cityInfos;
}