java - 如何在Java SAX中解析此XML？

我在Java中使用SAX解析器。我不确定：

1）在这种情况下我需要什么班级？我想我想拥有
的课程（请让我知道我的想法是否完全错误）：
-FosterHome（包含家庭和儿童的数组列表）
-Family（包含ArrayList的Child和一个String的parent）
-Child（包含ArrayList作为ChildID）

2）如何在startElement和endElement方法中处理这种情况

造成问题的原因是ChildID同时出现在ChildList和RemainingChildList中。感谢任何可以帮助我的人。

<FosterHome>
<Orphanage>Happy Days Daycare</Orphanage>
<Location>Apple Street</Location>
<Families>
    <Family>
        <Parent>Adams</ParentID>
        <ChildList>
            <ChildID>Child1</ChildID>
            <ChildID>Child2</ChildID>
        </ChildList>
    </Family>
    <Family>
        <Parent>Adams</ParentID>
        <ChildList>
            <ChildID>Child3</ChildID>
            <ChildID>Child4</ChildID>
        </ChildList>
    </Family>
</Families>
<RemainingChildList>
<ChildID>Child5</ChildID>
<ChildID>Child6</ChildID>
</RemainingChildList>
</FosterHome>

最佳答案

要处理来自不同父元素的ChildID元素，可以分别在输入ChildList和RemainingChildList的startElement（）处理程序方法时保存当前状态。然后，当您输入ChildID的endElement（）处理程序方法时，将根据保存的状态处理当前的ChildID（例如，在FosterHome类中填充适当的字段）。

例如：

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;

import java.io.CharArrayReader;
import java.io.CharArrayWriter;
import java.io.IOException;

public class XmlParser {

static void parse(String xml, Handler handler) throws SAXException, ParserConfigurationException, IOException
{
    SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
    XMLReader reader = saxParserFactory.newSAXParser().getXMLReader();
    reader.setContentHandler(handler);
    reader.parse(new InputSource(new CharArrayReader(xml.toCharArray())));
}

static class Handler extends DefaultHandler {

    CharArrayWriter contents = new CharArrayWriter();

    static enum STATE { Family, Remaining }
    STATE state;

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException
    {
        if (qName.equals("ChildList"))
            state = STATE.Family;
        else if (qName.equals("RemainingChildList"))
            state = STATE.Remaining;
        else if (qName.equals("ChildID"))
            contents.reset();
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException
    {
        if (qName.equals("ChildID"))
            System.out.println(contents.toString() + " [" + state + "]");
    }

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

public static void main(String[] args) throws Exception
{
    String xml = "<FosterHome>\n" +
        "<Orphanage>Happy Days Daycare</Orphanage>\n" +
        "<Location>Apple Street</Location>\n" +
        "<Families>\n" +
        "    <Family>\n" +
        "        <ParentID>Adams</ParentID>\n" +
        "        <ChildList>\n" +
        "            <ChildID>Child1</ChildID>\n" +
        "            <ChildID>Child2</ChildID>\n" +
        "        </ChildList>\n" +
        "    </Family>\n" +
        "    <Family>\n" +
        "        <ParentID>Adams</ParentID>\n" +
        "        <ChildList>\n" +
        "            <ChildID>Child3</ChildID>\n" +
        "            <ChildID>Child4</ChildID>\n" +
        "        </ChildList>\n" +
        "    </Family>\n" +
        "</Families>\n" +
        "<RemainingChildList>\n" +
        "<ChildID>Child5</ChildID>\n" +
        "<ChildID>Child6</ChildID>\n" +
        "</RemainingChildList>\n" +
        "</FosterHome>";

    parse(xml, new Handler());
}
}

关于java - 如何在Java SAX中解析此XML？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/8176590/