将XML数据文件写入文本文件

debugcn 发表于 Dev

s0lus

我在一个文件夹中有几个XML文件。我想将XML数据文件写入文本文件。但是我不知道该怎么做。:(

样本XML文件：

<?xml version = "1.0"?>
<note>
<to> Mat </to>
<from> Tim </from>
<head> Black </head>
<body> Yellow </body>
</note>

这是我的代码：

public class ReadXML extends DefaultHandler {

Boolean noteTag = false;
Boolean toTag = false;
Boolean fromTag = false;
Boolean headTag = false;
Boolean bodyTag = false;

static final String NOTE = "note";
static final String TO = "to";
static final String FROM = "from";
static final String HEAD = "head";
static final String BODY = "body";

public void read() throws Exception {

    SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser();

    File folder = new File("D:\\Source Code\\NetBeans\\Java\\BGPU\\ParseXMLFile");
    File[] listOfFiles = folder.listFiles();

    for (File file : listOfFiles) {
        if (file.isFile() && file.getName().endsWith(".xml")) {
            saxParser.parse(file, this);
            System.out.println();
        }
    }
}

@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

    if (qName.equalsIgnoreCase(NOTE)) {
        noteTag = true;
    }

    if (qName.equalsIgnoreCase(TO)) {
        toTag = true;
    }

    if (qName.equalsIgnoreCase(FROM)) {
        fromTag = true;
    }

    if (qName.equalsIgnoreCase(HEAD)) {
        headTag = true;
    }

    if (qName.equalsIgnoreCase(BODY)) {
        bodyTag = true;
    }
}

@Override
public void characters(char ch[], int start, int length) throws SAXException {

    if (fromTag.equals(true)) {
        System.out.println("FROM: " + new String(ch, start, length));
        }

    if (toTag.equals(true)) {
        System.out.println("TO: " + new String(ch, start, length));
        toTag = false;
    }

    if (headTag.equals(true)) {
        System.out.println("HEAD: " + new String(ch, start, length));
        headTag = false;
    }
}

@Override
public void endElement(String uri, String localName, String qName) throws SAXException {

    if (qName.equalsIgnoreCase(NOTE)) {
        noteTag = false;
    }

    if (qName.equalsIgnoreCase(TO)) {
        toTag = false;
    }

    if (qName.equalsIgnoreCase(FROM)) {
        fromTag = false;
    }

    if (qName.equalsIgnoreCase(HEAD)) {
        headTag = false;
    }

    if (qName.equalsIgnoreCase(BODY)) {
        bodyTag = false;
    }
}

public void save(String filename) throws Exception {

}

请帮助我完成save（）方法。

亚当

我建议不要使用SAX，这是一个使用XPath的示例。您可以使用java.util.FileWriter写入文件。

public class Test {
    public static void main(String[] args) throws Exception {
        BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"));

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse("test.xml");
        XPathFactory xPathFactory = XPathFactory.newInstance();
        writer.append(xPathFactory.newXPath().compile("//note/to").evaluate(document));
        writer.newLine();
        writer.append(xPathFactory.newXPath().compile("//note/from").evaluate(document));
        writer.newLine();
        writer.append(xPathFactory.newXPath().compile("//note/head").evaluate(document));
        writer.newLine();
        writer.append(xPathFactory.newXPath().compile("//note/body").evaluate(document));
        writer.newLine();
        writer.close();
    }
}

如果您真的必须使用SAX，这是一种更清洁的方法

public class ReadXml {

    public static void main(String[] args) throws Exception {
        new ReadXml().read();
    }

    public void read() throws Exception {

        SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser();

        File folder = new File(".");
        File[] listOfFiles = folder.listFiles();

        for (File file : listOfFiles) {
            if (file.isFile() && file.getName().endsWith(".xml")) {

                Handler handler = new Handler();
                saxParser.parse(file, handler);
                save(handler, file.getName() + ".txt");
            }
        }
    }

    private void save(Handler handler, String filename) throws IOException {
        BufferedWriter writer = new BufferedWriter(new FileWriter(filename));
        writer.append(handler.getFrom());
        writer.newLine();
        writer.append(handler.getTo());
        writer.newLine();
        writer.append(handler.getHead());
        writer.newLine();
        writer.append(handler.getBody());
        writer.newLine();
        writer.close();
    }

    private class Handler extends DefaultHandler {

        private StringBuilder content;
        private String to;
        private String from;
        private String body;
        private String head;

        @Override
        public void startElement(String uri, String localName, String qName,
                Attributes attributes) throws SAXException {

            content = new StringBuilder();
        }

        @Override
        public void characters(char ch[], int start, int length)
                throws SAXException {
            content.append(ch, start, length);
        }

        @Override
        public void endElement(String uri, String localName, String qName)
                throws SAXException {

            if ("to".equals(qName)) {
                to = content.toString();
            } else if ("from".equals(qName)) {
                from = content.toString();
            } else if ("body".equals(qName)) {
                body = content.toString();
            } else if ("head".equals(qName)) {
                head = content.toString();
            }
        }

        public String getTo() {
            return to;
        }

        public String getFrom() {
            return from;
        }

        public String getBody() {
            return body;
        }

        public String getHead() {
            return head;
        }

    }
}

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