Android网络访问与数据解析
16lz
2021-01-25
使用HttpUrlConnection访问网络
在过去，Android中发送Http请求的方式一般有两种：HttpUrlConnection和HttpClient.由于HttpClient的API数量太多导致扩展性很差，在Android6.0系统中HttpClient的功能被完全去除了。
@Override public void onClick(View view) { if (view.getId() == R.id.send_request) { sendRequestWithHttpUrlConnection(); } } private void sendRequestWithHttpUrlConnection() { //在Android3.0之后所有网络请求均需要在异步线程中执行 new Thread(new Runnable() { @Override public void run() { HttpURLConnection connection = null; BufferedReader reader = null; try { //向百度发送请求 URL url = new URL("https://www.baidu.com"); //使用构造的url开启一个连接 connection = (HttpURLConnection) url.openConnection(); //设置网络请求方式为GET,主要需要大写 connection.setRequestMethod("GET"); //设置连接超时时间 connection.setConnectTimeout(8000); //设置读取超时时间 connection.setReadTimeout(8000); InputStream is = connection.getInputStream(); //对获取到的输入流数据进行读取 reader = new BufferedReader(new InputStreamReader(is)); StringBuilder response = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { //对读取到的数据进行拼接 response.append(line); } //对读取到的数据进行显示 showResponse(response.toString()); } catch (IOException e) { e.printStackTrace(); } finally { //关闭对应的流操作 if (reader != null) { try { reader.close(); } catch (IOException e) { e.printStackTrace(); } } //断开连接 if (connection != null) { connection.disconnect(); } } } }).start(); } private void showResponse(final String result) { runOnUiThread(new Runnable() { @Override public void run() { //只要在主线程中才能进行Ui操作 responseText.setText(result); } }); }URL的书写一定不能出现错误
数据解析
解析XMl数据
使用Apache在本地搭建一个网页服务器，并在服务器上准备以下xml数据
lisa girl Bob boy Mike boy Pull解析
Student实体类
public class Student { private String name; private String gender; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } @Override public String toString() { return "Student{" + "name='" + name + '\'' + ", gender='" + gender + '\'' + '}'; } /** * 使用okHttp发送网络请求 */ private void sendRequestWithOkHttp() { new Thread(new Runnable() { @Override public void run() { try { OkHttpClient client = new OkHttpClient(); Request request = new Request.Builder() //指定访问的服务器地址是电脑本机 .url("http://10.0.2.2/test.xml") .build(); Response response = client.newCall(request).execute(); //取得返回的数据 String responseData = response.body().string(); Log.d("MainActivity", " " + responseData); parseXmlWithPull(responseData); } catch (IOException e) { e.printStackTrace(); } } }).start(); } private void parseXmlWithPull(String xmlData) { try { //构造XmlPullParserFactory对象进一步得到XmlPullParse对象 XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); XmlPullParser xmlPullParser = factory.newPullParser(); //将服务器返回的xml数据设置进去开始解析 xmlPullParser.setInput(new StringReader(xmlData)); int eventType = xmlPullParser.getEventType(); //未遍历到xml文件的结尾 while (eventType != XmlPullParser.END_DOCUMENT) { String nodeName = xmlPullParser.getName(); switch (eventType) { //开始解析节点 case XmlPullParser.START_TAG: { if ("name".equals(nodeName)) { //使用xmlPullParser.nextText()方法取出对应的值 student.setName(xmlPullParser.nextText()); } else if ("gender".equals(nodeName)) { student.setGender(xmlPullParser.nextText()); } break; } //完成解析某个节点 case XmlPullParser.END_TAG: { if ("student".equals(nodeName)) { Log.d("MainActivity", " " + student.toString()); } break; } default: break; } eventType = xmlPullParser.next(); } } catch (XmlPullParserException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }Log日志如下
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SAX解析
public class ContentHandler extends DefaultHandler { private String nodeName; private StringBuilder name; private StringBuilder gender; //开始XML解析时调用 @Override public void startDocument() throws SAXException { //变量初始化 name = new StringBuilder(); gender = new StringBuilder(); } //开始解析某个节点时调用 @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { //记录下当前节点名称 nodeName = localName; } //在获取节点中的内容时调用 @Override public void characters(char[] ch, int start, int length) throws SAXException { //根据节点名判断要将内容添加到哪个对象中 if ("name".equals(nodeName)) { //拼接数据 name.append(ch, start, length); } else if ("gender".equals(nodeName)) { gender.append(ch, start, length); } } //完成解析某个节点时调用 @Override public void endElement(String uri, String localName, String qName) throws SAXException { if ("student".equals(localName)) { Log.d("ContentHandler", "name is " + name.toString().trim()); Log.d("ContentHandler", "gender is " + gender.toString().trim()); //将StringBuilder清空，避免影响下一次数据的读取 name.setLength(0); gender.setLength(0); } } //完成整个XML解析时调用，一般调用父类的方法即可 @Override public void endDocument() throws SAXException { super.endDocument(); }} private void parseXmlWithSAX(String responseData) { try { //获取SAXParseFactory对象 SAXParserFactory factory = SAXParserFactory.newInstance(); //使用SAXParseFactory对象进一步获取到XMLReader对象 XMLReader xmlReader = factory.newSAXParser().getXMLReader(); ContentHandler handler = new ContentHandler(); //将ContentHandler实例设置到XMLReader中 xmlReader.setContentHandler(handler); //开始解析 xmlReader.parse(new InputSource(new StringReader(responseData))); } catch (SAXException e) { e.printStackTrace(); } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }Log日志
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DOM解析
//DOM解析XML数据 private void parseXmlWithDOM(String responseData) { try { //获取DOM解析器的工厂实例 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //从工厂实例中获取DOM解析器 DocumentBuilder builder = factory.newDocumentBuilder(); //将要解析的xml数据读入解析器 Document document = builder.parse(new InputSource(new StringReader(responseData))); //得到xml文件中名称为student的节点集合 NodeList studentNodes = document.getElementsByTagName("student"); //遍历该节点集合，获取集合中的元素及其子元素的值 for (int i = 0; i < studentNodes.getLength(); i++) { Element student = (Element) studentNodes.item(i); String name = student.getElementsByTagName("name").item(0).getFirstChild().getNodeValue(); String gender = student.getElementsByTagName("gender").item(0).getFirstChild().getNodeValue(); Log.d("DOM", "name is " + name); Log.d("DOM", "gender is " + gender); } } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }Log日志
图片.png解析Json数据
在服务器准备Json数据源
[ { "name": "Mike", "gender": "boy", "age": 19, "family": [ { "name": "Bob", "gender": "boy", "age": 21 }, { "name": "Lily", "gender": "girl", "age": 18 } ] }, { "name": "lisa", "gender": "girl", "age": 20 }]JSONObject解析
//使用JsonObject解析Json数据 private void parseJsonWithJsonObject(String responseData) { try { //将服务器返回的数据传入JsonArray对象中 JSONArray jsonArray = new JSONArray(responseData); for (int i = 0; i < jsonArray.length(); i++) { //从JsonArray对象中取出最外层的JsonObject对象 JSONObject jsonObject = jsonArray.getJSONObject(i); String name = jsonObject.getString("name"); String gender = jsonObject.getString("gender"); int age = jsonObject.getInt("age"); Log.d("Json", "name is " + name); Log.d("Json", "gender is " + gender); Log.d("Json", "age is " + age); //进一步从最外层的JsonObject获取次外层的JsonArray JSONArray jsonArray_family = jsonObject.getJSONArray("family"); for (int j = 0; j < jsonArray_family.length(); j++) { //获取次外层的JsonObject对象 JSONObject jsonObject_family = jsonArray_family.getJSONObject(j); String family_name = jsonObject_family.getString("name"); String family_gender = jsonObject_family.getString("gender"); int family_age = jsonObject_family.getInt("age"); Log.d("Json", "family_name is " + family_name); Log.d("Json", "family_gender is " + family_gender); Log.d("Json", "family_age is " + family_age); } } } catch (JSONException e) { e.printStackTrace(); } }Log日志
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