修改XML文件

Question

例如，我有这个文件XML：

<http auto-config="true">
        <intercept-url access="ROLE_ADMIN,ROLE_USER" pattern="/"/>
        <intercept-url access="ROLE_ADMIN,ROLE_USER" pattern="/index*"/>
        <intercept-url access="ROLE_ADMIN" pattern="/page1"/>
        <intercept-url access="ROLE_ADMIN" pattern="/page2"/>
        <intercept-url access="ROLE_ADMIN" pattern="/page33"/>

</http>

我想更改此行的元素“访问”的文本：

<intercept-url access="ROLE_ADMIN" pattern="/page33"/>

所以我创建此代码：

import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
 import org.w3c.dom.Document;
 import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import com.sun.xml.internal.ws.org.objectweb.asm.Attribute;

public class ChangeXMLFile {

    public static void main(String argv[]) {

       try {
        String filepath = "D:\\Myfile.xml";
        DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
        Document doc = docBuilder.parse(filepath);


        Node company = doc.getFirstChild();

        Node staff = doc.getElementsByTagName("intercept-url").item(0);

        NodeList list = staff.getChildNodes();

        for (int i = 0; i < list.getLength(); i++) {

                   Node node = list.item(i);


           if ("pattern".equals(node.getNodeName())) {
                if(("/page33").equals(node.getTextContent())){


                    NamedNodeMap attr = staff.getAttributes();
                    Node nodeAttr = attr.getNamedItem("access");
                    nodeAttr.setTextContent("ROLE_ANONYM");
                }

           }




        }


        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(new File(filepath));
        transformer.transform(source, result);

        System.out.println("Done");

       } catch (ParserConfigurationException pce) {
        pce.printStackTrace();
       } catch (TransformerException tfe) {
        tfe.printStackTrace();
       } catch (IOException ioe) {
        ioe.printStackTrace();
       } catch (SAXException sae) {
        sae.printStackTrace();
       }
    }
}

但是我没有改变。 如何让程序读取xml文件的每一行并根据内容的“模式”文本更改“访问”属性？

Answer 1

您的层次结构级别都错了。 尝试这样的事情：

        DocumentBuilderFactory docFactory = DocumentBuilderFactory
                .newInstance();
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
        Document doc = docBuilder.parse(...;

        NodeList list = doc.getElementsByTagName("intercept-url");

        for (int i = 0; i < list.getLength(); i++) {
            Element node = (Element) list.item(i);
            Attr pattern = node.getAttributeNode("pattern");
            if (pattern != null && pattern.getValue().equals("/page33")) {
                node.setAttribute("access", "ROLE_ANONYM");
            }
        }

        TransformerFactory transformerFactory = TransformerFactory
                .newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(...);
        transformer.transform(source, result);

Answer 2

您应该检查调试，

    Node staff = doc.getElementsByTagName("intercept-url").item(0);

    NodeList list = staff.getChildNodes();

list为空：staff是您的第一个“ intercept-url”节点，因此，当您尝试获取其子级时，结果列表为空。

尝试这样的事情：

    NodeList staffList = doc.getElementsByTagName("intercept-url");