我有一个存储为DOM文档的XML文件,我希望将其漂亮地打印到控制台上,最好不使用外部库。 [我知道这个问题已经在此站点上问过多次,但是以前的答案对我来说都没有。我正在使用Java 8,所以这也许是我的代码与以前的问题有所不同的地方?我也尝试过使用从Web上找到的代码手动设置变压器,但这只是导致了not found
错误。
这是我的代码,当前仅在控制台左侧的新行上输出每个xml元素。
import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class Test {
public Test(){
try {
//java.lang.System.setProperty("javax.xml.transform.TransformerFactory", "org.apache.xalan.xsltc.trax.TransformerFactoryImpl");
DocumentBuilderFactory dbFactory;
DocumentBuilder dBuilder;
Document original = null;
try {
dbFactory = DocumentBuilderFactory.newInstance();
dBuilder = dbFactory.newDocumentBuilder();
original = dBuilder.parse(new InputSource(new InputStreamReader(new FileInputStream("xml Store - Copy.xml"))));
} catch (SAXException | IOException | ParserConfigurationException e) {
e.printStackTrace();
}
StringWriter stringWriter = new StringWriter();
StreamResult xmlOutput = new StreamResult(stringWriter);
TransformerFactory tf = TransformerFactory.newInstance();
//tf.setAttribute("indent-number", 2);
Transformer transformer = tf.newTransformer();
transformer.setOutputProperty(OutputKeys.METHOD, "xml");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.transform(new DOMSource(original), xmlOutput);
java.lang.System.out.println(xmlOutput.getWriter().toString());
} catch (Exception ex) {
throw new RuntimeException("Error converting to String", ex);
}
}
public static void main(String[] args){
new Test();
}
}
我想这个问题与原始文件中的空白文本节点(即只有空白的文本节点)有关。您应该尝试在解析后使用以下代码以编程方式删除它们。如果不删除它们,则Transformer
将保留它们。
original.getDocumentElement().normalize();
XPathExpression xpath = XPathFactory.newInstance().newXPath().compile("//text()[normalize-space(.) = '']");
NodeList blankTextNodes = (NodeList) xpath.evaluate(original, XPathConstants.NODESET);
for (int i = 0; i < blankTextNodes.getLength(); i++) {
blankTextNodes.item(i).getParentNode().removeChild(blankTextNodes.item(i));
}
为回复Espinosa的评论,这是“ 原始xml尚未(部分)缩进或包含新行的解决方案。
背景
启发该解决方案的文章摘录(请参阅下面的[[References]:] 根据DOM规范,标记外部的空格是完全有效的,并且已正确保留。要删除它们,我们可以使用XPath的normalize-space定位所有空白节点,然后首先将其删除。
Java代码public static String toPrettyString(String xml, int indent) {
try {
// Turn xml string into a document
Document document = DocumentBuilderFactory.newInstance()
.newDocumentBuilder()
.parse(new InputSource(new ByteArrayInputStream(xml.getBytes("utf-8"))));
// Remove whitespaces outside tags
document.normalize();
XPath xPath = XPathFactory.newInstance().newXPath();
NodeList nodeList = (NodeList) xPath.evaluate("//text()[normalize-space()='']",
document,
XPathConstants.NODESET);
for (int i = 0; i < nodeList.getLength(); ++i) {
Node node = nodeList.item(i);
node.getParentNode().removeChild(node);
}
// Setup pretty print options
TransformerFactory transformerFactory = TransformerFactory.newInstance();
transformerFactory.setAttribute("indent-number", indent);
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
// Return pretty print xml string
StringWriter stringWriter = new StringWriter();
transformer.transform(new DOMSource(document), new StreamResult(stringWriter));
return stringWriter.toString();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
样本用法
String xml = "<root>" + //
"\n " + //
"\n<name>Coco Puff</name>" + //
"\n <total>10</total> </root>";
System.out.println(toPrettyString(xml, 4));
输出
<root>
<name>Coco Puff</name>
<total>10</total>
</root>
参考文献