java 有用的Java实用程序类或方法。

Posted 2021-05-08

import java.io.IOException;
import java.io.StringReader;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Node;
import org.w3c.dom.DOMException;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSException;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
 * Class to format Strings that contain XMLs.
 *
 * @author Zygimantas
 * @see http://stackoverflow.com/questions/139076/how-to-pretty-print-xml-from-java
 */
public class XmlFormatter {

    public String format(String xml) {

        try {
            final InputSource src = new InputSource(new StringReader(xml));
            final Node document = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(src).getDocumentElement();
            final Boolean keepDeclaration = xml.startsWith("<?xml");

            final DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance();
            final DOMImplementationLS impl = (DOMImplementationLS) registry.getDOMImplementation("LS");
            final LSSerializer writer = impl.createLSSerializer();

            writer.getDomConfig().setParameter("format-pretty-print", Boolean.TRUE); // Set this to true if the output needs to be beautified.
            writer.getDomConfig().setParameter("xml-declaration", keepDeclaration); // Set this to true if the declaration is needed to be outputted.

            return writer.writeToString(document);
        } catch (ParserConfigurationException | SAXException | IOException |
                ClassNotFoundException | InstantiationException |
                IllegalAccessException | ClassCastException | DOMException |
                LSException e) {
            throw new RuntimeException(e);
        }
    }
}