Sax的Xml解析方式

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一、Sax解析格式实例

test.xml

注意本段解析文件中<heading> 和<body>之中都有<font>,所以要考虑一一对应问题

以<to>George</to>为例：startElement读取到了qName为to标签，紧接着character函数运行获取标签后的内容George，endElement函数读取/to标签，以此类推执行下去。

<note level="5">    <to>George</to>    <to>Jack</to>    <to>Jash</to>    <to>Ryan</to>    <from>John</from>    <heading>        <font>正黑</font>        <title>Reminder</title>    </heading>    <body>        <font>宋体</font>        <message>Don't forget the meeting!</message>    </body></note>

TestSax.java

public class Test {    public static void main(String[] args) {        SAXParserFactory factory = SAXParserFactory.newInstance();        try {            SAXParser parser = factory.newSAXParser();            Note note = new Note();            parser.parse(new File("res/test.xml"), new MyHandler(note));            System.out.println(note.getHeading());            System.out.println(note.getBody());            System.out.println(note.getLevel());            System.out.println(note.getTo());        } catch (ParserConfigurationException e) {            e.printStackTrace();        } catch (SAXException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }}

Note.java

public class Note {    private List<String> to;    private String from;    private Heading heading;    private Body body;    private int level;    public List<String> getTo() {        if (to == null) {            to = new ArrayList<>();        }        return to;    }    public void setTo(List<String> to) {        this.to = to;    }    public String getFrom() {        return from;    }    public void setFrom(String from) {        this.from = from;    }    public Heading getHeading() {        return heading;    }    public void setHeading(Heading heading) {        this.heading = heading;    }    public Body getBody() {        return body;    }    public void setBody(Body body) {        this.body = body;    }    public int getLevel() {        return level;    }    public void setLevel(int level) {        this.level = level;    }}

Heading.java

public class Heading {    private String font;    private String title;    public String getFont() {        return font;    }    public void setFont(String font) {        this.font = font;    }    public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }    @Override    public String toString() {        return "Heading{" +                "font='" + font + '\'' +                ", title='" + title + '\'' +                '}';    }}

Body.java

public class Body {    private String font;    private String message;    public String getFont() {        return font;    }    public void setFont(String font) {        this.font = font;    }    public String getMessage() {        return message;    }    public void setMessage(String message) {        this.message = message;    }    @Override    public String toString() {        return "Body{" +                "font='" + font + '\'' +                ", message='" + message + '\'' +                '}';    }}

MyHandler.java

public class MyHandler extends DefaultHandler {    private Note note;    private Stack<String> nameStack;    public MyHandler(Note note) {        this.note = note;    }    @Override    public void startDocument() throws SAXException {        super.startDocument();        nameStack = new Stack<>();    }    @Override    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {        super.startElement(uri, localName, qName, attributes);        nameStack.push(qName);//qName表示的是note，form,heading,font这样的标签。        switch (qName) {            case "note":                note.setLevel(Integer.parseInt(attributes.getValue("level")));                break;            case "heading":                note.setHeading(new Heading());                break;            case "body":                note.setBody(new Body());                break;        }        // System.out.println(qName);    }    @Override    public void characters(char[] ch, int start, int length) throws SAXException {        super.characters(ch, start, length);        String s = new String(ch, start, length).trim();        System.out.println(ch);        System.out.println("=======");        if (!s.isEmpty()) {//            System.out.println(s);            switch (nameStack.peek()) {                case "to":                    note.getTo().add(s);                    break;                case "from":                    note.setFrom(s);                    break;                case "font":                    switch (nameStack.get(nameStack.size() - 2)) {//下标从零开始的所以要减2                        case "heading":                            note.getHeading().setFont(s);                            break;                        case "body":                            note.getBody().setFont(s);                            break;                    }                    break;                case "title":                    note.getHeading().setTitle(s);                    break;                case "message":                    note.getBody().setMessage(s);                    break;//                case "heading"://                    note.setHeading(s);//                    break;//                case "body"://                    note.setBody(s);//                    break;            }        }    }    @Override    public void endElement(String uri, String localName, String qName) throws SAXException {        super.endElement(uri, localName, qName);        nameStack.pop();//用来是释放栈的内存    }    @Override    public void endDocument() throws SAXException {        super.endDocument();    }}

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