如何使用 Java 和 XmlSchema Core 解析 XSD 并读取所有复杂元素及其子元素

Question

我正在使用 Apache XmlSchema Core 库解析 XSD 文件并获取所有元素及其子类型（数据类型、maxOccurs 等）。我正在关注文档 Apache XML SCHEMA CORE 并尝试这样做。但是在导航到某个点之后，我有点困惑。有人可以指导我如何遍历 XSD 文件并获取所有元素及其子元素以及相关信息吗？

我能够在我的 schema 元素中获取所有 XSD 信息我只想知道如何从我的根 RootFood 访问子元素并获取其相关信息信息。任何帮助将不胜感激。

我试图继续下去，这是我目前所拥有的：元素 RootFood 属于 class XmlSchemaGroupParticle 的实例。我试图调试代码以找到与我的 rootParticles 关联的元素，它有一个名为 items 的字段，其中我有我的 food 元素 items->[0]->namedDelegate->qName->localPart 但是当我尝试在 rootParticles 上添加 GET 方法来获取 items 然后没有这样的方法。

XmlSchemaParticle 扩展了以下 classes：XmlSchemaAnnotated、XmlSchemaObject 并实现了接口 XmlSchemaObjectBase，但其中 none 有名为 Items.

的字段

以下是我目前的 Java 代码，我尝试了几种方法：

public class XMLSchemaCore {

    public static void main(String[] args) throws URISyntaxException,
        FileNotFoundException,
        UnsupportedEncodingException {
            String xsdPath = Paths.get(XMLSchemaCore.class.getClassLoader().getResource("test.xsd").toURI()).toFile().getAbsolutePath();
            String filePath = Path.of(xsdPath).toString();

            InputStream is = new FileInputStream(filePath);
            XmlSchemaCollection schemaCol = new XmlSchemaCollection();

            // Schema contain the complete XSD content which needs to be parsed
            XmlSchema schema = schemaCol.read(new StreamSource(is));
            // schema.write(System.out);
            for (Map.Entry<QName, XmlSchemaElement> entry: schema.getElements().entrySet()) {
                // Root element and its contents
                QName parentElementName = entry.getKey();
                XmlSchemaElement parentElementValues = entry.getValue();

                // Get the elements based on the Root element
                XmlSchemaElement root = schema.getElementByName(parentElementName);

                // Get the type of the root element
                XmlSchemaType type = root != null ? root.getSchemaType() : null;

                // Check if the root element is of Complex type
                if (type instanceof XmlSchemaComplexType) {
                    // Get the Particles associated with the element
                    XmlSchemaParticle rootParticles = ((XmlSchemaComplexType) type).getParticle();

                    // Check particle belongs to which type
                    if (rootParticles instanceof XmlSchemaAny) {
                        System.out.println("Any Schema Type");

                    } else if (rootParticles instanceof XmlSchemaElement) {
                        System.out.println("Element Schema Type");

                    } else if (rootParticles instanceof XmlSchemaGroupParticle) {
                        System.out.println("Group Schema Type");
                        System.out.println(rootParticles);
                        System.out.println(rootParticles);

                    } else if (rootParticles instanceof XmlSchemaGroupRef) {
                        System.out.println("Group Ref Schema Type");

                    }
                }
            }

        }

}

以下是我的 XSD 文件：

<xs:schema attributeFormDefault="unqualified"
    elementFormDefault="qualified"
    xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="RootFood">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="food">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element type="xs:string" name="name" />
                            <xs:element type="xs:string" name="price" />
                            <xs:element type="xs:string" name="description" />
                            <xs:element type="xs:short" name="calories" />
                            <xs:element name="ingredients">
                                <xs:complexType>
                                    <xs:sequence>
                                        <xs:element type="xs:string" name="ingredient"
                                            maxOccurs="unbounded" minOccurs="0" />
                                    </xs:sequence>
                                </xs:complexType>
                            </xs:element>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
</xs:schema>

Answer 1

在尝试了很多事情之后，我能够让代码正常工作。在这里发布代码，因为它可能会对计划使用 Apache XMLSchema Core Library for XML/XSD parsing 的人有所帮助。我知道这有多令人沮丧，因为我们在 Internet 上没有关于此解析库的一些好的示例。希望这有帮助。

基本上，此代码将解析整个 XSD 文件并根据其父元素和子元素将元素存储在 HashMap 中。您可以获得任何 XSD 元素的父级，也可以获得与子级相关的信息，例如其父级等。检查 XmlSchemaElement 以获取有关每个子级信息的更多详细信息：

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import javax.xml.namespace.QName;
import javax.xml.transform.stream.StreamSource;

import org.apache.ws.commons.schema.XmlSchema;
import org.apache.ws.commons.schema.XmlSchemaAny;
import org.apache.ws.commons.schema.XmlSchemaCollection;
import org.apache.ws.commons.schema.XmlSchemaComplexType;
import org.apache.ws.commons.schema.XmlSchemaElement;
import org.apache.ws.commons.schema.XmlSchemaGroupRef;
import org.apache.ws.commons.schema.XmlSchemaParticle;
import org.apache.ws.commons.schema.XmlSchemaSequence;
import org.apache.ws.commons.schema.XmlSchemaSequenceMember;
import org.apache.ws.commons.schema.XmlSchemaType;

public class XMLSchemaCore {

    private static XmlSchemaCollection xmlSchemaCollection;
    private static Map<QName, List<XmlSchemaElement>> xsdElements = new HashMap<QName, List<XmlSchemaElement>>();
    private static List<XmlSchemaElement> schemaElements = new ArrayList<XmlSchemaElement>();

    public static void main(String[] args) throws URISyntaxException, FileNotFoundException, UnsupportedEncodingException {
        // Path for the file which is stored within the Resource folder
        String xsdPath = Paths.get(XMLSchemaCore.class.getClassLoader().getResource("test.xsd").toURI()).toFile().getAbsolutePath();
        String filePath = Path.of(xsdPath).toString();

        InputStream is = new FileInputStream(filePath);
        xmlSchemaCollection = new XmlSchemaCollection();

        // Schema contain the complete XSD content which needs to be parsed
        XmlSchema schema = xmlSchemaCollection.read(new StreamSource(is));
        // schema.write(System.out);

        // Get the root element from XSD
        Map.Entry<QName, XmlSchemaElement> entry = schema.getElements().entrySet().iterator().next();
        QName rootElement = entry.getKey();

        // Get all the elements based on the parent element
        XmlSchemaElement childElement = xmlSchemaCollection.getElementByQName(rootElement);

        // Call method to get all the child elements
        getChildElementNames(childElement);

        String element = "" + xsdElements.entrySet().stream().map(e -> e.getKey() + " -- " + String.join(", ", e.getValue().stream().map(v -> v
                            .getQName().toString()).collect(Collectors.toList()))).collect(Collectors.toList());

        System.out.println(element);
    }

    // Method to check for the child elements and return list
    private static void getChildElementNames(XmlSchemaElement element) {

        // Get the type of the element
        XmlSchemaType elementType = element != null ? element.getSchemaType() : null;

        // Confirm if the element is of Complex type
        if (elementType instanceof XmlSchemaComplexType) {
            // Get all particles associated with that element Type
            XmlSchemaParticle allParticles = ((XmlSchemaComplexType) elementType).getParticle();

            // Check particle belongs to which type
            if (allParticles instanceof XmlSchemaAny) {
                System.out.println("Any Schema Type");

            } else if (allParticles instanceof XmlSchemaElement) {
                System.out.println("Element Schema Type");

            } else if (allParticles instanceof XmlSchemaSequence) {
                // System.out.println("Sequence Schema Type");
                final XmlSchemaSequence xmlSchemaSequence = (XmlSchemaSequence) allParticles;
                final List<XmlSchemaSequenceMember> items = xmlSchemaSequence.getItems();
                items.forEach((item) -> {
                    XmlSchemaElement itemElements = (XmlSchemaElement) item;
                    schemaElements.add(itemElements);
                    // System.out.println(" Parent : " + element.getQName() + " -- Child : " +
                    // itemElements.getQName());
                    //Call the method to add the current element as child
                    addChild(element.getQName(), itemElements);
                    // Call method recursively to get all subsequent element
                    getChildElementNames(itemElements);
                    schemaElements = new ArrayList<XmlSchemaElement>();
                });

            } else if (allParticles instanceof XmlSchemaGroupRef) {

            }
        }
    }

    // Add child elements based on its parent
    public static void addChild(QName qName, XmlSchemaElement child) {
        List<XmlSchemaElement> values = xsdElements.get(qName);
        if (values == null) {
            values = new ArrayList<XmlSchemaElement>();
        }
        values.add(child);
        xsdElements.put(qName, values);
    }

}

如何使用 Java 和 XmlSchema Core 解析 XSD 并读取所有复杂元素及其子元素

How to parse XSD and read all the complex elements and its child elements using the Java and XmlSchema Core

java

xml

xsd

xmlschema