res中：
<WebView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/web_view"
/>
java中：
WebView webView = findViewById(R.id.web_view);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebViewClient(new WebViewClient()); // 网页跳转在WebView中显示
webView.loadUrl("http://www.baidu.com");
.xml中：
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
...
android:requestLegacyExternalStorage="true"
android:usesCleartextTraffic="true">
1.httpconnection
textView = findViewById(R.id.text_view);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://www.baidu.com");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
});
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
textView.setText(response);
}
});
}
.xml中：
添加权限控制，如上
2.OkHttp
.gradle中：
implementation ‘com.squareup.okhttp3:okhttp:3.10.0‘
java中：
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://www.baidu.com")
.build();
try {
Response response = client.newCall(request).execute();
String responseData = response.body().string();
showResponse(responseData);
} catch (IOException e) {
e.printStackTrace();
}
.xml中：
引入权限控制，如上
1.PULL
// 解析xml文件
private void parseXMLWithPull(String xmlData) {
XmlPullParserFactory factory = null;
try {
factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
// 开始解析某个节点
case XmlPullParser.START_TAG: {
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
}
// 完成解析某个节点
case XmlPullParser.END_TAG: {
if ("app".equals(nodeName)) {
System.out.println("id is " + id);
System.out.println("name is " + name);
System.out.println("version is " + version);
}
break;
}
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.SAX
.java中：
继承DefaultHandler类：
public class ContentHandler extends DefaultHandler {
private String nodeName;
private StringBuilder id;
private StringBuilder name;
private StringBuilder version;
/**
* 开始解析的时候调用
*/
@Override
public void startDocument() throws SAXException {
super.startDocument();
id = new StringBuilder();
name = new StringBuilder();
version = new StringBuilder();
}
/**
* 开始解析某个节点的时候调用
*/
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
super.startElement(uri, localName, qName, attributes);
// 记录当前节点名称
nodeName = localName;
}
/**
* 获取节点内容的时候调用
*/
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
super.characters(ch, start, length);
// 根据当前节点名称判断将内容添加到哪个StringBuilder对象中
if ("id".equals(nodeName)) {
id.append(ch,start,length);
} else if ("name".equals(nodeName)) {
name.append(ch,start,length);
} else if ("version".equals(nodeName)) {
version.append(ch,start,length);
}
}
/**
* 完成某个节点的时候调用
*/
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
super.endElement(uri, localName, qName);
if ("app".equals(localName)) {
System.out.println("id is " + id.toString().trim());
System.out.println("name is " + name.toString().trim());
System.out.println("version is " + version.toString().trim());
// 最后要将StringBuilder清空掉,不然影响下一次内容读取
id.setLength(0);
name.setLength(0);
version.setLength(0);
}
}
/**
* 完成整个xml解析的时候调用
*/
@Override
public void endDocument() throws SAXException {
super.endDocument();
}
}
java.activity中:
private void parseXMLWithSAX(String xmlData) {
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
XMLReader xmlReader = factory.newSAXParser().getXMLReader();
ContentHandler handler = new ContentHandler();
// 将ContentHandler的实例设置到XMLReader中
xmlReader.setContentHandler(handler);
// 开始执行解析
xmlReader.parse(new InputSource(new StringReader(xmlData)));
} catch (Exception e) {
e.printStackTrace();
}
}
1.JSONObject
private void parseJSONWithJSONObject(String jsonData) {
try {
JSONArray jsonArray = new JSONArray(jsonData);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String id = jsonObject.getString("id");
String name = jsonObject.getString("name");
String version = jsonObject.getString("version");
System.out.println("id is " + id);
System.out.println("name is " + name);
System.out.println("version is " + version);
}
} catch (Exception e) {
e.printStackTrace();
}
}
2.GSON
.gradle中：
implementation ‘com.google.code.gson:gson:2.8.4‘
java中：
新建App类，作为映射对象
java.Activity中：
private void parseJSONWithGSON(String jsonData) {
Gson gson = new Gson();
List<App> appList = gson.fromJson(jsonData, new TypeToken<List<App>>() {
}.getType());
for (App app:appList
) {
System.out.println("id is " + app.getId());
System.out.println("name is " +app.getName());
System.out.println("version is " +app.getVersion());
}
}
原文：https://www.cnblogs.com/ssy197/p/13705284.html