是否可以有XML，适当的XSD，可以选择maxOccurs =“ 1”，而每个元素都可以使用minOccurs =“ 1”？

我有有效的XSD，但我无法制作xml，不适合它。

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<xs:schema xmlns="urn:hl7-org:v3" xmlns:xs="http://www.w3.org/2001/XMLSchema"
           targetNamespace="urn:hl7-org:v3"
           elementFormDefault="qualified">

    <xs:element name="Main" type="Main"/>
    <xs:complexType name="Child1">
        <xs:sequence>
            <xs:element name="f1" type="xs:string"/>
        </xs:sequence>
    </xs:complexType>
    <xs:complexType name="Child2">
        <xs:sequence>
            <xs:element name="f1" type="xs:string"/>
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="Main">
        <xs:sequence>
            <xs:choice>
                <xs:element name="child1" type="Child1"
                            nillable="true"
                            minOccurs="1"
                            maxOccurs="1"/>
                <xs:element name="child2" type="Child2"
                            nillable="true"
                            minOccurs="1"
                            maxOccurs="1"/>
            </xs:choice>
        </xs:sequence>
    </xs:complexType>
</xs:schema>

如果这不可能，那么架构为何有效？使用JAXB为此模式生成源，创建对象，但验证未通过-[发现无效的内容以元素'child1'开始。此时，预计不会有任何子元素。]

import cz.atria.common.datagenerator.ValueProvider;
import cz.atria.common.datagenerator.ValueProviderRandom;
import org.hl7.v3.Child1;
import org.hl7.v3.Main;
import org.hl7.v3.ObjectFactory;
import org.junit.Test;

import javax.xml.XMLConstants;
import javax.xml.bind.*;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import java.io.File;

public void test1() throws Exception {
    JAXBContext jaxbContext = JAXBContext.newInstance(Main.class.getPackage().getName());
    SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
    Schema schema = schemaFactory.newSchema(new File("D:\\cts2\\jaxbtest\\src\\main\\xsd\\schema1.xsd"));
    Marshaller marshaller = jaxbContext.createMarshaller();
    ObjectFactory of = new ObjectFactory();
    marshaller.setSchema(schema);
    Main main = new Main();
    Child1 child1 = new Child1();

    child1.setF1("test");

    main.setChild1(child1);

    final ValidationEventHandler validationEventHandler = marshaller.getEventHandler();
    marshaller.setEventHandler(new ValidationEventHandler() {
        @Override
        public boolean handleEvent(ValidationEvent event) {
            /*if(event.getLocator().getObject() instanceof Child1) {
                return true;
            } else {
                return validationEventHandler.handleEvent(event);
            }*/
            return validationEventHandler.handleEvent(event);
        }
    });

    System.out.println(marshaller.getEventHandler());
    marshaller.marshal(main, System.out);
}