我有一个包含XML的Java字符串，没有换行或缩进。我想把它变成一个字符串与格式良好的XML。我怎么做呢?
String unformattedXml = "<tag><nested>hello</nested></tag>";
String formattedXml = new [UnknownClass]().format(unformattedXml);
注意:我的输入是一个字符串。输出是一个字符串。
(基本)模拟结果:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<tag>
<nested>hello</nested>
</tag>
</root>
当前回答
如果你不需要缩进那么多，但一些换行，这可能是足够的简单regex…
String leastPrettifiedXml = uglyXml.replaceAll("><", ">\n<");
代码很好，而不是因为缺少缩进而导致的结果。
(对于有缩进的解，请参见其他答案。)
其他回答
使用scala:
import xml._
val xml = XML.loadString("<tag><nested>hello</nested></tag>")
val formatted = new PrettyPrinter(150, 2).format(xml)
println(formatted)
如果你依赖scala-library.jar，你也可以在Java中这样做。它是这样的:
import scala.xml.*;
public class FormatXML {
public static void main(String[] args) {
String unformattedXml = "<tag><nested>hello</nested></tag>";
PrettyPrinter pp = new PrettyPrinter(150, 3);
String formatted = pp.format(XML.loadString(unformattedXml), TopScope$.MODULE$);
System.out.println(formatted);
}
}
PrettyPrinter对象是用两个整数构造的，第一个是最大行长，第二个是缩进步骤。
嗯…面对这样的事情，这是一个已知的bug… 只需添加这个OutputProperty ..
transformer.setOutputProperty(OutputPropertiesFactory.S_KEY_INDENT_AMOUNT, "8");
希望这对你有所帮助……
现在已经是2012年了，Java可以比以前的XML做更多的事情，我想在我公认的答案之外添加一个替代方案。这在Java 6之外没有依赖关系。
import org.w3c.dom.Node;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.InputSource;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.StringReader;
/**
* Pretty-prints xml, supplied as a string.
* <p/>
* eg.
* <code>
* String formattedXml = new XmlFormatter().format("<tag><nested>hello</nested></tag>");
* </code>
*/
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 = Boolean.valueOf(xml.startsWith("<?xml"));
//May need this: System.setProperty(DOMImplementationRegistry.PROPERTY,"com.sun.org.apache.xerces.internal.dom.DOMImplementationSourceImpl");
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 (Exception e) {
throw new RuntimeException(e);
}
}
public static void main(String[] args) {
String unformattedXml =
"<?xml version=\"1.0\" encoding=\"UTF-8\"?><QueryMessage\n" +
" xmlns=\"http://www.SDMX.org/resources/SDMXML/schemas/v2_0/message\"\n" +
" xmlns:query=\"http://www.SDMX.org/resources/SDMXML/schemas/v2_0/query\">\n" +
" <Query>\n" +
" <query:CategorySchemeWhere>\n" +
" \t\t\t\t\t <query:AgencyID>ECB\n\n\n\n</query:AgencyID>\n" +
" </query:CategorySchemeWhere>\n" +
" </Query>\n\n\n\n\n" +
"</QueryMessage>";
System.out.println(new XmlFormatter().format(unformattedXml));
}
}
我把它们混合在一起，写了一个小程序。它从xml文件中读取并打印出来。而不是xzy给出你的文件路径。
public static void main(String[] args) throws Exception {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setValidating(false);
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new FileInputStream(new File("C:/Users/xyz.xml")));
prettyPrint(doc);
}
private static String prettyPrint(Document document)
throws TransformerException {
TransformerFactory transformerFactory = TransformerFactory
.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
DOMSource source = new DOMSource(document);
StringWriter strWriter = new StringWriter();
StreamResult result = new StreamResult(strWriter);transformer.transform(source, result);
System.out.println(strWriter.getBuffer().toString());
return strWriter.getBuffer().toString();
}
对于那些寻找快速和肮脏的解决方案的人——它不需要XML是100%有效的。例如，在REST / SOAP日志的情况下(你永远不知道其他人发送了什么;-))
我发现并改进了一个我在网上找到的代码剪辑，我认为这仍然是一个有效的可能的方法:
public static String prettyPrintXMLAsString(String xmlString) {
/* Remove new lines */
final String LINE_BREAK = "\n";
xmlString = xmlString.replaceAll(LINE_BREAK, "");
StringBuffer prettyPrintXml = new StringBuffer();
/* Group the xml tags */
Pattern pattern = Pattern.compile("(<[^/][^>]+>)?([^<]*)(</[^>]+>)?(<[^/][^>]+/>)?");
Matcher matcher = pattern.matcher(xmlString);
int tabCount = 0;
while (matcher.find()) {
String str1 = (null == matcher.group(1) || "null".equals(matcher.group())) ? "" : matcher.group(1);
String str2 = (null == matcher.group(2) || "null".equals(matcher.group())) ? "" : matcher.group(2);
String str3 = (null == matcher.group(3) || "null".equals(matcher.group())) ? "" : matcher.group(3);
String str4 = (null == matcher.group(4) || "null".equals(matcher.group())) ? "" : matcher.group(4);
if (matcher.group() != null && !matcher.group().trim().equals("")) {
printTabs(tabCount, prettyPrintXml);
if (!str1.equals("") && str3.equals("")) {
++tabCount;
}
if (str1.equals("") && !str3.equals("")) {
--tabCount;
prettyPrintXml.deleteCharAt(prettyPrintXml.length() - 1);
}
prettyPrintXml.append(str1);
prettyPrintXml.append(str2);
prettyPrintXml.append(str3);
if (!str4.equals("")) {
prettyPrintXml.append(LINE_BREAK);
printTabs(tabCount, prettyPrintXml);
prettyPrintXml.append(str4);
}
prettyPrintXml.append(LINE_BREAK);
}
}
return prettyPrintXml.toString();
}
private static void printTabs(int count, StringBuffer stringBuffer) {
for (int i = 0; i < count; i++) {
stringBuffer.append("\t");
}
}
public static void main(String[] args) {
String x = new String(
"<soap:Envelope xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"><soap:Body><soap:Fault><faultcode>soap:Client</faultcode><faultstring>INVALID_MESSAGE</faultstring><detail><ns3:XcbSoapFault xmlns=\"\" xmlns:ns3=\"http://www.someapp.eu/xcb/types/xcb/v1\"><CauseCode>20007</CauseCode><CauseText>INVALID_MESSAGE</CauseText><DebugInfo>Problems creating SAAJ object model</DebugInfo></ns3:XcbSoapFault></detail></soap:Fault></soap:Body></soap:Envelope>");
System.out.println(prettyPrintXMLAsString(x));
}
输出如下:
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<soap:Fault>
<faultcode>soap:Client</faultcode>
<faultstring>INVALID_MESSAGE</faultstring>
<detail>
<ns3:XcbSoapFault xmlns="" xmlns:ns3="http://www.someapp.eu/xcb/types/xcb/v1">
<CauseCode>20007</CauseCode>
<CauseText>INVALID_MESSAGE</CauseText>
<DebugInfo>Problems creating SAAJ object model</DebugInfo>
</ns3:XcbSoapFault>
</detail>
</soap:Fault>
</soap:Body>
</soap:Envelope>
