dom解析占用内存大（我这边需要解析各种各样的kml文件，有时4-5M的kml文件使用dom解析很多手机就内存溢出了），也需要引入第三方库，所以使用相对于节省内存很多、不需引入其他库的sax解析就是很好的选择了。因为sax解析比较复杂的xml文件特别麻烦，所以整理了一个简化android sax解析的工具。
实现思路：和Android Touch事件传递机制一样，把需要子解析器解析的节点往下传递。
如果有进一步简化的方法，欢迎交流！email:csqwyyx@163.com。
示例程序：https://github.com/John-Chen/EasySaxParser
简化工具SaxParser：
public abstract class SaxParser {
protected String curQName;
protected StringBuilder curValue = new StringBuilder();
protected SaxParser saxParser;
protected String saxParserQName;
/**
* 需要生成子SaxParser的节点名称
*/
protected HashSet<String> childParserQNames;
public SaxParser() {
}
public SaxParser(HashSet<String> childParserQNames) {
this.childParserQNames = childParserQNames;
}
protected void startElement(String uri, String localName, String qName, Attributes attributes) {
if(qName == null){
return;
}
if(saxParser != null){
saxParser.startElement(uri, qName, qName, attributes);
}else if(childParserQNames != null && childParserQNames.contains(qName)){
this.saxParser = dispatchTo(qName, attributes);
if(this.saxParser != null){
this.saxParserQName = qName;
saxParser.parserStart(attributes);
}
}else{
curQName = qName;
if(curValue.length() > 0){
curValue.delete(0, curValue.length());
}
}
}
protected void endElement(String uri, String localName, String qName) {
if(qName == null){
return;
}
if(qName.equals(saxParserQName)){
if(saxParser != null){
saxParser.parserEnd();
}
saxParser = null;
saxParserQName = null;
}else if(saxParser != null){
saxParser.endElement(uri, qName, qName);
}else{
parserElementEnd(qName, curValue.toString());
curQName = null;
if(curValue.length() > 0){
curValue.delete(0, curValue.length());
}
}
}
protected void characters(char[] ch, int start, int length) {
if(saxParser != null){
saxParser.characters(ch, start, length);
}else{
String data = new String(ch, start, length);
if(data.length() > 0 && curQName != null){
curValue.append(data);
}
}
}
/**
* 开始解析一个输入流
* @param is 文件输入流
* @param rootParserQName 解析的文件根节点
* @param rootParser 根解析器
*/
public static void start(InputStream is,
final String rootParserQName,
final SaxParser rootParser){
try {
SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
parser.parse(is, new DefaultHandler(){
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
if(qName == null){
return;
}
if(rootParser != null){
rootParser.startElement(uri, qName, qName, attributes);
}else if(qName.equals(rootParserQName)){
rootParser.parserStart(attributes);
}
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if(rootParser != null){
rootParser.characters(ch, start, length);
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if(qName == null){
return;
}
if(qName.contains(rootParserQName)){
if(rootParser != null){
rootParser.parserEnd();
}
}else if(rootParser != null){
rootParser.endElement(uri, qName, qName);
}
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 节点解析开始
*/
public abstract void parserStart(Attributes attributes);
/**
* 一个子节点解析结束
* @param value characters获得的值
*/
public abstract void parserElementEnd(String qName, String value);
/**
* 解析事件需要向下传递，返回需要传递的子SaxParser
*/
public abstract SaxParser dispatchTo(String qName, Attributes attributes);
/**
* 节点解析结束
*/
public abstract void parserEnd();
}
需要解析的xml文件test.xml:
<?xml version="1.0" encoding="UTF-8"?> <kml xmlns:gx="http://www.google.com/kml/ext/2.2"> <Document id="123">
<description>abc</description>
<author>csq</author>
<ExtendedData>
<Data name="TrackId">
<value>293156</value>
</Data>
<Data name="TrackTypeId">
<value>8</value>
</Data>
</ExtendedData> <Placemark>
<name>深圳湾公园</name>
<TimeStamp>
<when>2015-03-21T10:00:13Z</when>
</TimeStamp>
<Point>
<coordinates>113.93946,22.48955,9.0</coordinates>
</Point>
</Placemark> </Document> </kml>
开始解析：
根节点kml，根节点解析器KmlParser
SaxParser.start(getAssets().open("test.kml"), "kml", new Kml.KmlParser(kml));
部分节点解析实现：
public static class KmlParser extends SaxParser {
private Kml kml;
public KmlParser(Kml kml) {
super(new HashSet<String>());
this.kml = kml;
childParserQNames.add("Document");
}
@Override
public void parserStart(Attributes attributes) {
}
@Override
public void parserElementEnd(String qName, String value) {
}
@Override
public SaxParser dispatchTo(String qName, Attributes attributes) {
if(qName.equals("Document")){
return new Document.DocumentParser(kml);
}
return null;
}
@Override
public void parserEnd() {
}
}
public static class DocumentParser extends SaxParser {
private Kml kml;
private Document document;
public DocumentParser(Kml kml) {
super(new HashSet<String>());
this.kml = kml;
childParserQNames.add("ExtendedData");
childParserQNames.add("Placemark");
}
@Override
public void parserStart(Attributes attributes) {
document = new Document();
document.id = attributes.getValue("id");
}
@Override
public void parserElementEnd(String qName, String value) {
if(document == null){
return;
}
if(qName.equals("description")){
document.description = value;
}else if(qName.equals("author")){
document.author = value;
}
}
@Override
public SaxParser dispatchTo(String qName, Attributes attributes) {
if(document == null){
return null;
}
if(qName.equals("ExtendedData")){
return new ExtendedData.ExtendedDataParser(document);
}else if(qName.equals("Placemark")){
return new Placemark.PlacemarkParser(document);
}
return null;
}
@Override
public void parserEnd() {
kml.document = document;
}
}
public static class PlacemarkParser extends SaxParser {
private Document document;
private Placemark placemark;
public PlacemarkParser(Document document) {
super(new HashSet<String>(1));
childParserQNames.add("Point");
this.document = document;
}
@Override
public void parserStart(Attributes attributes) {
placemark = new Placemark();
}
@Override
public void parserElementEnd(String qName, String value) {
if(qName.equals("name")){
placemark.name = value;
}else if(qName.equals("when")){
placemark.when = value;
}
}
@Override
public SaxParser dispatchTo(String qName, Attributes attributes) {
if(qName.equals("Point")){
return new Point.PointParser(placemark);
}
return null;
}
@Override
public void parserEnd() {
document.placemark = placemark;
}
}
public static class ExtendedDataParser extends SaxParser {
private Document document;
private ExtendedData extendedData;
public ExtendedDataParser(Document document) {
super(new HashSet<String>(1));
childParserQNames.add("Data");
this.document = document;
}
@Override
public void parserStart(Attributes attributes) {
extendedData = new ExtendedData();
}
@Override
public void parserElementEnd(String qName, String value) {
}
@Override
public SaxParser dispatchTo(String qName, Attributes attributes) {
if(qName.equals("Data")){
return new Data.DataParser(extendedData);
}
return null;
}
@Override
public void parserEnd() {
document.extendedDatas = extendedData;
}
}
......
解析结果：