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
这是我自己问题的答案。我将各种结果的答案结合起来，编写了一个输出XML的类。
不保证它如何响应无效的XML或大型文档。
package ecb.sdw.pretty;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
/**
* 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 XmlFormatter() {
}
public String format(String unformattedXml) {
try {
final Document document = parseXmlFile(unformattedXml);
OutputFormat format = new OutputFormat(document);
format.setLineWidth(65);
format.setIndenting(true);
format.setIndent(2);
Writer out = new StringWriter();
XMLSerializer serializer = new XMLSerializer(out, format);
serializer.serialize(document);
return out.toString();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private Document parseXmlFile(String in) {
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource(new StringReader(in));
return db.parse(is);
} catch (ParserConfigurationException e) {
throw new RuntimeException(e);
} catch (SAXException e) {
throw new RuntimeException(e);
} catch (IOException 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));
}
}
其他回答
java有一个静态方法U.formatXml(string)。生活的例子
import com.github.underscore.U;
public class MyClass {
public static void main(String args[]) {
String xml = "<tag><nested>hello</nested></tag>";
System.out.println(U.formatXml("<?xml version=\"1.0\" encoding=\"UTF-8\"?><root>" + xml + "</root>"));
}
}
输出:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<tag>
<nested>hello</nested>
</tag>
</root>
如果您确信您有一个有效的XML，那么这个很简单，并且避免了XML DOM树。可能有一些错误，如果你看到任何错误，请评论
public String prettyPrint(String xml) {
if (xml == null || xml.trim().length() == 0) return "";
int stack = 0;
StringBuilder pretty = new StringBuilder();
String[] rows = xml.trim().replaceAll(">", ">\n").replaceAll("<", "\n<").split("\n");
for (int i = 0; i < rows.length; i++) {
if (rows[i] == null || rows[i].trim().length() == 0) continue;
String row = rows[i].trim();
if (row.startsWith("<?")) {
// xml version tag
pretty.append(row + "\n");
} else if (row.startsWith("</")) {
// closing tag
String indent = repeatString(" ", --stack);
pretty.append(indent + row + "\n");
} else if (row.startsWith("<")) {
// starting tag
String indent = repeatString(" ", stack++);
pretty.append(indent + row + "\n");
} else {
// tag data
String indent = repeatString(" ", stack);
pretty.append(indent + row + "\n");
}
}
return pretty.toString().trim();
}
这是我自己问题的答案。我将各种结果的答案结合起来，编写了一个输出XML的类。
不保证它如何响应无效的XML或大型文档。
package ecb.sdw.pretty;
import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
/**
* 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 XmlFormatter() {
}
public String format(String unformattedXml) {
try {
final Document document = parseXmlFile(unformattedXml);
OutputFormat format = new OutputFormat(document);
format.setLineWidth(65);
format.setIndenting(true);
format.setIndent(2);
Writer out = new StringWriter();
XMLSerializer serializer = new XMLSerializer(out, format);
serializer.serialize(document);
return out.toString();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private Document parseXmlFile(String in) {
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
InputSource is = new InputSource(new StringReader(in));
return db.parse(is);
} catch (ParserConfigurationException e) {
throw new RuntimeException(e);
} catch (SAXException e) {
throw new RuntimeException(e);
} catch (IOException 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));
}
}
我总是使用下面的函数:
public static String prettyPrintXml(String xmlStringToBeFormatted) {
String formattedXmlString = null;
try {
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setValidating(true);
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
InputSource inputSource = new InputSource(new StringReader(xmlStringToBeFormatted));
Document document = documentBuilder.parse(inputSource);
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
StreamResult streamResult = new StreamResult(new StringWriter());
DOMSource dOMSource = new DOMSource(document);
transformer.transform(dOMSource, streamResult);
formattedXmlString = streamResult.getWriter().toString().trim();
} catch (Exception ex) {
StringWriter sw = new StringWriter();
ex.printStackTrace(new PrintWriter(sw));
System.err.println(sw.toString());
}
return formattedXmlString;
}
有一个非常好的命令行XML实用程序叫做xmlstarlet(http://xmlstar.sourceforge.net/)，它可以做很多事情，很多人都在使用它。
您可以使用Runtime以编程方式执行此程序。然后读入格式化的输出文件。它具有比几行Java代码所能提供的更多选项和更好的错误报告。
下载xmlstarlet: http://sourceforge.net/project/showfiles.php?group_id=66612&package_id=64589
