[devdiv精华转载] android开发四种方式解析字符串----JSON、SAX、DOM、XML

原帖地址:http://www.devdiv.com/forum.php?mod=viewthread&tid=60304&extra=page%3D1%26filter%3Ddigest%26digest%3D1%26digest%3D1

当是练习吧，分别以JSON、SAX、DOM、XML(android.util.XML)来解析字符串。
个人感觉这四种方式的实现由难到易的顺序是：SAX→XML→DOM→JSON。

JSON解析的内容如下，文件名为devdiv.json，存于工程的assets目录下：

{
"code":"1",
"result":{
"title":"Devdiv移动开发社区",
"title_url":"http://www.devdiv.com/forum.php",
"development_forum_name":"开发讨论区",
"development_forum":[
{"name":"Windows Phone论坛","url":"http://www.devdiv.com/forum-windows-phone-mobile-1.html"},
{"name":"Android论坛","url":"http://www.devdiv.com/forum-android-1.html"},
{"name":"iOS/iPhone论坛","url":"http://www.devdiv.com/forum-iphone-1.html"}
]
}
}

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剩下三个解析内容如下，文件名为devdiv.xml，存于工程的assets目录下：

<root>
<title>Devdiv移动开发社区</title>
<body>开发讨论区</body>
<item url="http://www.devdiv.com/forum-windows-phone-mobile-1.html">Windows Phone论坛</item>
<item url="http://www.devdiv.com/forum-android-1.html">Android论坛</item>
<item url="http://www.devdiv.com/forum-iphone-1.html">iOS/iPhone论坛</item>
</root>

复制代码

本例子解析后显示效果：

代码如下：

package lab.sodino.string;
import java.io.IOException;
import java.io.InputStream;
import java.util.Vector;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import android.app.Activity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.method.LinkMovementMethod;
import android.text.style.StyleSpan;
import android.text.style.URLSpan;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class TextAct extends Activity {
public static final String TAG = "ANDROID_LAB";
private Button btnJSON;
private Button btnSAX;
private Button btnDOM;
private Button btnXML;
private BtnListener btnListener;
private TextView txtInfo;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnListener = new BtnListener();
btnJSON = (Button) findViewById(R.id.btnJSON);
btnSAX = (Button) findViewById(R.id.btnSAX);
btnDOM = (Button) findViewById(R.id.btnDOM);
btnXML = (Button) findViewById(R.id.btnXML);
btnJSON.setOnClickListener(btnListener);
btnSAX.setOnClickListener(btnListener);
btnDOM.setOnClickListener(btnListener);
btnXML.setOnClickListener(btnListener);
txtInfo = (TextView) findViewById(R.id.txtInfo);
}
private void inflateTextViewByBean(Bean bean) {
int spanCount = 4;
int[] start = new int[spanCount];
int[] end = new int[spanCount];
StringBuffer buffer = new StringBuffer();
buffer.append(bean.type + "\n");
buffer.append(bean.title + "\n");
start[0] = buffer.length();
buffer.append(bean.development_forum_name + "\n");
end[0] = buffer.length();
for (int i = 0; i < bean.vecName.size(); i++) {
start[i + 1] = buffer.length();
buffer.append(bean.vecName.get(i) + "\n");
end[i + 1] = buffer.length();
}
SpannableString spannableString = new SpannableString(buffer.toString());
spannableString.setSpan(new StyleSpan(Typeface.ITALIC), start[0], end[0],
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
for (int i = 0; i < bean.vecName.size(); i++) {
spannableString.setSpan(new URLSpan(bean.vecUrl.get(i)), start[i + 1], end[i + 1],
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}
txtInfo.setText(spannableString);
txtInfo.setMovementMethod(LinkMovementMethod.getInstance());
}
class BtnListener implements Button.OnClickListener {
public void onClick(View view) {
if (view == btnJSON) {
showInfoFromJSON();
} else if (view == btnSAX) {
showInfoFromSAXParser();
} else if (view == btnDOM) {
showInfoFromDOM();
} else if (view == btnXML) {
showInfoFromXML();
}
}
}
public void showInfoFromJSON() {
Bean bean = new Bean();
bean.type = "Inflated by JSON\n";
String content = "";
InputStream is = null;
try {
is = getAssets().open("devdiv.json");
byte[] data = new byte[is.available()];
is.read(data);
content = new String(data);
Log.d(TAG, "content=" + content);
JSONObject jsonContent = new JSONObject(content);
int code = jsonContent.getInt("code");
// 假设默认code为1时才是正确的json数据。
if (code == 1) {
JSONObject jsonResult = jsonContent.getJSONObject("result");
bean.title = jsonResult.getString("title");
bean.development_forum_name = jsonResult.getString("development_forum_name");
bean.vecName = new Vector<String>();
bean.vecUrl = new Vector<String>();
JSONArray devArr = jsonResult.getJSONArray("development_forum");
String tmp = "";
for (int i = 0; i < devArr.length(); i++) {
JSONObject obj = devArr.getJSONObject(i);
tmp = obj.getString("name");
bean.vecName.add(tmp);
tmp = obj.getString("url");
bean.vecUrl.add(tmp);
}
inflateTextViewByBean(bean);
} else {
Log.d(TAG, "A error occur when parse a json file.");
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ie) {
ie.printStackTrace();
}
}
}
public void showInfoFromXML() {
Bean bean = new Bean();
bean.type = "Inflated by XML\n";
bean.vecName = new Vector<String>();
bean.vecUrl = new Vector<String>();
MyXMLHandler xmlHandler = null;
InputStream is = null;
xmlHandler = new MyXMLHandler(bean);
try {
is = getAssets().open("devdiv.xml");
// 一句话就OK了。
android.util.Xml.parse(is, android.util.Xml.Encoding.UTF_8, xmlHandler);
} catch (IOException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ie) {
ie.printStackTrace();
}
}
inflateTextViewByBean(bean);
}
public void showInfoFromDOM() {
Bean bean = new Bean();
bean.type = "Inflated by DOM\n";
bean.vecName = new Vector<String>();
bean.vecUrl = new Vector<String>();
InputStream is = null;
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
try {
is = getAssets().open("devdiv.xml");
NodeList list = null;
DocumentBuilder domBuilder = domFactory.newDocumentBuilder();
Document doc = domBuilder.parse(is);
// 获取根目录
Element rootElement = doc.getDocumentElement();
// 输出[rootElement=root]
Log.d(TAG, "rootElement=" + rootElement.getNodeName());
list = rootElement.getElementsByTagName("title");
// 在已提前获只有一个title的情况下直接去取list.item(0)
bean.title = list.item(0).getTextContent();
// 在已提前获只有一个body的情况下直接去取list.item(0)
list = rootElement.getElementsByTagName("body");
bean.development_forum_name = list.item(0).getTextContent();
// 多个item的读取情形
list = rootElement.getElementsByTagName("item");
for (int i = 0; i < list.getLength(); i++) {
Node node = list.item(i);
bean.vecUrl.add(node.getAttributes().item(0).getTextContent());
bean.vecName.add(node.getTextContent());
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ie) {
ie.printStackTrace();
}
}
inflateTextViewByBean(bean);
}
public void showInfoFromSAXParser() {
Bean bean = new Bean();
bean.vecName = new Vector<String>();
bean.vecUrl = new Vector<String>();
bean.type = "Inflated by SAXParser\n";
InputStream is = null;
SAXParser parser = null;
MyXMLHandler xmlHandler = null;
try {
parser = SAXParserFactory.newInstance().newSAXParser();
xmlHandler = new MyXMLHandler(bean);
is = getAssets().open("devdiv.xml");
parser.parse(is, xmlHandler);
inflateTextViewByBean(bean);
} catch (IOException ie) {
ie.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (FactoryConfigurationError e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ie) {
ie.printStackTrace();
}
}
}
class MyXMLHandler extends DefaultHandler {
Bean bean;
String currentElement;
public MyXMLHandler(Bean bean) {
MyXMLHandler.this.bean = bean;
}
public void startDocument() throws SAXException {
Log.d(TAG, "MyXMLHandler startDocument");
}
public void endDocument() throws SAXException {
Log.d(TAG, "MyXMLHandler endDocument");
}
public void startElement(String uri, String localName, String qName, Attributes atts)
throws SAXException {
// Log.d(TAG, "MyXMLHandler startElement");
currentElement = localName;
if (localName.equals("item")) {
if (atts != null) {
for (int i = 0; i < atts.getLength(); i++) {
// 本例中atts.getLength()值为1
bean.vecUrl.add(atts.getValue(i));
Log.d(TAG, "add url[" + atts.getValue(i) + "]");
}
}
}
}
public void characters(char[] ch, int start, int length) throws SAXException {
String str = new String(ch, start, length);
// Log.d(TAG, "MyXMLHandler characters start=" + start + " len=" +
// length + " str[" + str
// + "]");
if (currentElement != null) {
String tmp = new String(ch, start, length);
if (currentElement.equals("title")) {
bean.title = tmp;
} else if (currentElement.equals("body")) {
bean.development_forum_name = tmp;
} else if (currentElement.equals("item")) {
bean.vecName.add(tmp);
Log.d(TAG, "add name[" + tmp + "]");
}
}
}
public void endElement(String uri, String localName, String qName) throws SAXException {
Log.d(TAG, "MyXMLHandler endDocument");
currentElement = null;
}
}
class Bean {
String type;
String title;
String development_forum_name;
Vector<String> vecName;
Vector<String> vecUrl;
}
}

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DOM解析中的Node.etTextContent()要求api-level至少为8。
现补充level为8以下的解析方法：

public void showInfoFromDOM() {
Bean bean = new Bean();
bean.type = "Inflated by DOM\n";
bean.vecName = new Vector<String>();
bean.vecUrl = new Vector<String>();
InputStream is = null;
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
try {
is = getAssets().open("devdiv.xml");
NodeList list = null;
DocumentBuilder domBuilder = domFactory.newDocumentBuilder();
Document doc = domBuilder.parse(is);
// 获取根目录
Element rootElement = doc.getDocumentElement();
// 输出[rootElement=root]
Log.d(TAG, "rootElement=" + rootElement.getNodeName());
list = rootElement.getElementsByTagName("title");
if (Integer.parseInt(Build.VERSION.SDK) >= 8) {
// 在已提前获只有一个title的情况下直接去取list.item(0)
bean.title = list.item(0).getTextContent();
// 在已提前获只有一个body的情况下直接去取list.item(0)
list = rootElement.getElementsByTagName("body");
bean.development_forum_name = list.item(0).getTextContent();
// 多个item的读取情形
list = rootElement.getElementsByTagName("item");
for (int i = 0; i < list.getLength(); i++) {
Node node = list.item(i);
bean.vecUrl.add(node.getAttributes().item(0).getTextContent());
bean.vecName.add(node.getTextContent());
}
} else {
// 在已提前获只有一个title的情况下直接去取list.item(0)
bean.title = list.item(0).getFirstChild().getNodeValue();
// 在已提前获只有一个body的情况下直接去取list.item(0)
list = rootElement.getElementsByTagName("body");
bean.development_forum_name = list.item(0).getFirstChild().getNodeValue();
// 多个item的读取情形
list = rootElement.getElementsByTagName("item");
for (int i = 0; i < list.getLength(); i++) {
Node node = list.item(i);
bean.vecUrl.add(node.getAttributes().getNamedItem("url").getNodeValue());
bean.vecName.add(node.getFirstChild().getNodeValue());
}
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ie) {
ie.printStackTrace();
}
}
inflateTextViewByBean(bean);
}

复制代码

posted on 2011-12-06 13:09 Evalon 阅读(445) 评论(0) 收藏举报

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Elan

[devdiv精华转载] android开发四种方式解析字符串----JSON、SAX、DOM、XML

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Elan

[devdiv精华转载] android开发 四种方式解析字符串----JSON、SAX、DOM、XML

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[devdiv精华转载] android开发四种方式解析字符串----JSON、SAX、DOM、XML