一、解析XML
格式的数据
1、准备工作
建立一个本地网页,访问http://192.168.2.118:7777/get_data.xml
,可以出现以下内容:
<apps>
<app>
<id>1</id>
<name>Goole Maps</name>
<version>1.0</version>
</app>
<app>
<id>2</id>
<name>Chrome</name>
<version>2.1</version>
</app>
<app>
<id>3</id>
<name>Google Play</name>
<version>2.3</version>
</app>
</apps>
如图:
2、Pull
解析
继续使用上文《Android网络技术(一)——WebView和HTTP协议》的代码。
主活动:
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try{
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.2.118:7777/get_data.xml")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
parseXMLWithPull(responseData);
// showResponse(responseData);
}catch (Exception e){
e.printStackTrace();
}
}
}).start();
}
private void parseXMLWithPull(String responseData) {
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
InputStream is = new ByteArrayInputStream(responseData.getBytes());
xmlPullParser.setInput(is, "utf-8");
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT){
String nodeName = xmlPullParser.getName();
switch (eventType){
// 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)){
Log.d(TAG, "-----------------------------");
Log.d(TAG, "id is "+id);
Log.d(TAG, "name is "+name);
Log.d(TAG, "version is "+version);
}
break;
}
default:
break;
}
eventType = xmlPullParser.next();
}
}catch (Exception e){
e.printStackTrace();
}
}
步骤:
- 在自定义的方法
parseXMLWithPull()
中处理数据,具体如下: - 先获取
XmlPullParserFactory
实例:XmlPullParserFactory.newInstance()
- 通过实例得到
XmlPullParser
对象:.newPullParser()
- 调用对象的方法将数据解析:
.setInput(new StringReader(数据))
- 获取对象的解析事件:
.getEventType()
【返回的事件对象类似游标】 - 判断所有解析未完成:
事件 != 对象.END_DOCUMENT
- 获取节点名:
对象.getName()
- 获取节点内具体内容:
对象.nextText()
- 节点开始:
对象.START_TAG
- 节点结束:
对象.END_TAG
针对安卓Q的安全设置:
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:usesCleartextTraffic="true"
...
运行:
3、SAX
解析
它比Pull
解析更加复杂,但语义更加清晰
通常先新建一个继承自DefaultHandler
类,并重写父类的5个方法:
public class MyHandler extends DefaultHandler {
@Override
public void startDocument() throws SAXException {
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
}
@Override
public void endDocument() throws SAXException {
}
}
实战:
新建一个ContentHandler
类:
public class ContentHandler extends DefaultHandler {
private String nodeName;
private StringBuilder id;
private StringBuilder name;
private StringBuilder version;
private static final String TAG = "ContentHandler";
@Override
public void startDocument() throws SAXException {
id = new StringBuilder();
name = new StringBuilder();
version = new StringBuilder();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
// 记录当前节点名
nodeName = localName;
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
// 根据当前节点名判断内容添加到哪一个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);
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
// 完成解析当前节点
if ("app".equals(localName)){
Log.d(TAG, "----------------------------------");
Log.d(TAG, "id is "+id.toString().trim());
Log.d(TAG, "name is "+name.toString().trim());
Log.d(TAG, "version is "+version.toString().trim());
// 最后将StringBuilder清空
id.setLength(0);
name.setLength(0);
version.setLength(0);
}
}
@Override
public void endDocument() throws SAXException {
super.endDocument();
}
}
修改主活动的代码:
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try{
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.2.118:7777/get_data.xml")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
parseXMLWithSAX(responseData);
// parseXMLWithPull(responseData);
// showResponse(responseData);
}catch (Exception e){
e.printStackTrace();
}
}
}).start();
}
private void parseXMLWithSAX(String responseData) {
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
XMLReader xmlReader = factory.newSAXParser().getXMLReader();
ContentHandler handler = new ContentHandler();
// 将创建的ContetnHandler实例添加到XMLReader中
xmlReader.setContentHandler(handler);
// 开始解析
xmlReader.parse(new InputSource(new StringReader(responseData)));
}catch (Exception e){
e.printStackTrace();
}
}
运行:
4、DOM
解析
自己查资料去,上面两种够用了。
二、解析JSON
格式的数据
1、准备工作
建立一个本地网页,访问http://192.168.2.118:7777/get_data.json
,可以出现以下内容:
[{"id":"5","version":"5.5","name":"路飞"},
{"id":"6","version":"7.0","name":"索隆"},
{"id":"7","version":"3.5","name":"乔治"}]
2、JSONObject
解析
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try{
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.2.118:7777/get_data.json")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
parseJSONWithJSONObject(responseData);
}catch (Exception e){
e.printStackTrace();
}
}
}).start();
}
private void parseJSONWithJSONObject(String responseData) {
try{
JSONArray jsonArray = new JSONArray(responseData);
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");
Log.d(TAG, "-----------------------------------------");
Log.d(TAG, "id is "+id);
Log.d(TAG, "name is "+name);
Log.d(TAG, "version is "+version);
}
}catch (Exception e){
e.printStackTrace();
}
}
3、GSON
解析
添加依赖:implementation 'com.google.code.gson:gson:2.8.6'
建一个基本类App
:
public class App {
private String id;
private String name;
private String version;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getVersion() {
return version;
}
public void setVersion(String version) {
this.version = version;
}
}
主活动:
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try{
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.2.118:7777/get_data.json")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
parseJSONWithGSON(responseData);
}catch (Exception e){
e.printStackTrace();
}
}
}).start();
}
private void parseJSONWithGSON(String responseData) {
Gson gson = new Gson();
List<App> appList = gson.fromJson(responseData, new TypeToken<List<App>>(){}.getType());
for (App app:appList){
Log.d(TAG, "---------------------------------");
Log.d(TAG, "id is "+app.getId());
Log.d(TAG, "name is "+app.getName());
Log.d(TAG, "version is "+app.getVersion());
}
}