怎样读取xml文件中指定标记的内容

[VincentTung]

有一个xml文件，内容如下
<?xml version="1.0" encoding="GB2312" ?>
<Root>
<IP>192.168.0.1</IP>
<IP>192.168.0.234</IP>
<IP>192.168.0.120</IP>
<IP>192.168.0.7</IP>
<IP>192.168.0.19</IP>

</Root>
我想把所有IP中的内容读出来，请问用Java怎么写？

[llongfeng2008]

[Quote=引用 5 楼 laitaogood 的回复:]
dom4j+xpath
相当简单
[/Quote]

最讨厌你这种人。人家是来问问题，会你就把问题给人家解决了。“dom4j+xpath”扔了这么句话啥意思？充大个儿呀？

[VincentTung]

import java.io.File;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class Xml {
public static void main(String[] args) {
try {
DocumentBuilderFactory factory = DocumentBuilderFactory
.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse(new File("d:\\123\\123.xml"));
Element rootElement = document.getDocumentElement();

NodeList list = rootElement.getElementsByTagName("IP");
Element element = (Element) list.item(0);
System.out.println(element.getChildNodes().item(0).getNodeValue());

} catch (Exception e) {
System.out.println("exception:" + e.getMessage());
}
}
}

这个只能读一条IP

[学习Java中]

Dom4j

package xml;

import java.io.File;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.QName;
import org.dom4j.io.SAXReader;

public class Dom4jTest {

	private SAXReader reader;
	private Document document;
	private static String path = "c:/Dom4jSample1.xml";

	public Dom4jTest(String str) throws DocumentException {
		reader = new SAXReader();
		document = reader.read(new File(str));
	}

	public static void main(String[] args) throws DocumentException {
		// TODO Auto-generated method stub
		Dom4jTest test = new Dom4jTest(path);	
		test.getInfo();

	}

	public void getInfo() {
		Element root = document.getRootElement();

		QName qname = new QName("IP");
		List<Element> list = root.elements(qname);

		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i).getText());
		}

	}

}

[VincentTung]

哇塞，成功了，谢谢高手。小弟再问一下，怎样往里面追加一条IP 呢？

[学习Java中]

[Quote=引用 3 楼 will88 的回复:]
哇塞，成功了，谢谢高手。小弟再问一下，怎样往里面追加一条IP 呢？
[/Quote]

	// 添加
	public void add(String add) throws IOException {

		Element root = document.getRootElement();
		Element e = root.addElement("IP");
		e.setText(add);
		writeFile(document);

	}

	// 写入文件
	private void writeFile(Document doc) throws IOException {
		FileWriter out = new FileWriter(path);
		doc.write(out);
		out.flush();
		out.close();
	}

[laitaogood]

dom4j+xpath
相当简单

[火龙果被占用了]

如果你用 JDK 5 或者以上版的话，可以直接使用 XPath 进行查找：

import java.io.InputStream;

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;

public class XPathTest {

    public static void main(String[] args) throws XPathExpressionException {
        String xpath = "//Root/IP";
        InputSource is = readInputSource("test.xml");

        XPathFactory factory = XPathFactory.newInstance();
        XPath path = factory.newXPath();
        NodeList nodes = (NodeList)path.evaluate(xpath, is, XPathConstants.NODESET);
        for(int i = 0, k = nodes.getLength(); i < k; i++) {
            System.out.println(nodes.item(i).getTextContent());
        }
    }

    private static InputSource readInputSource(String resource) {
        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
        return new InputSource(is);
    }
}

[liuyuhua0066]

[Quote=引用 6 楼 llongfeng2008 的回复:]

引用 5 楼 laitaogood 的回复:
dom4j+xpath
相当简单


最讨厌你这种人。人家是来问问题，会你就把问题给人家解决了。“dom4j+xpath”扔了这么句话啥意思？充大个儿呀？
[/Quote]点到为止，有时候思路比答案重要，授之于鱼不如授之于渔