JAXB没有为空的xs:element标签创建类

Question

我正在将项目从jaxb 1.0迁移到2.1.当使用jaxb 2.1(通过ant xjc任务)从xsd生成类时,生成的类缺少没有任何内容的元素:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="unqualified">
....
<xs:element name="get-all-services-partners-request"/>

但是,当元素具有内容时会生成文件,如下所示:

 <xs:element name="catalog-full-service-request">
   <xs:complexType>
     <xs:sequence>
       <xs:element name="service-id" type="xs:string" minOccurs="0"/>
       <xs:element name="log-id" type="xs:string" minOccurs="0"/>
     </xs:sequence>
   </xs:complexType>
 </xs:element>

为什么会这样？前一组生成的类(使用jaxb 1.0)包含所有元素的类,而不仅仅是包含内容的类.

如何让jaxb生成这些缺失的类？我真的没有权利改变xsd(但如果真的有必要可以这样做).

Answer 1

好消息是你不需要生成"缺失的类",我将在下面举例说明.

schema.xsd

下面是XML架构的简化版本.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    elementFormDefault="unqualified">

    <xs:element name="get-all-services-partners-request" />

    <xs:complexType name="foo">
        <xs:sequence>
            <xs:element name="bar" type="xs:string" />
        </xs:sequence>
    </xs:complexType>

</xs:schema>

富

JAXB(JSR-222)实现将为每个复杂类型(命名或匿名)创建一个类.在上面的XML模式中,只有一个复杂的类型(foo),因此只生成模型类.

package forum12990635;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "foo", propOrder = {
    "bar"
})
public class Foo {

    @XmlElement(required = true)
    protected String bar;

    public String getBar() {
        return bar;
    }

    public void setBar(String value) {
        this.bar = value;
    }

}

的ObjectFactory

与命名复杂类型对应的全局元素与@XmlElementDecl注释的类上的注释相对应@XmlRegistry(请参阅:http: //blog.bdoughan.com/2012/07/jaxb-and-root-elements.html).

package forum12990635;

import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.XmlElementDecl;
import javax.xml.bind.annotation.XmlRegistry;
import javax.xml.namespace.QName;


@XmlRegistry
public class ObjectFactory {

    private final static QName _GetAllServicesPartnersRequest_QNAME = new QName("", "get-all-services-partners-request");

    public ObjectFactory() {
    }

    public Foo createFoo() {
        return new Foo();
    }

    @XmlElementDecl(namespace = "", name = "get-all-services-partners-request")
    public JAXBElement<Object> createGetAllServicesPartnersRequest(Object value) {
        return new JAXBElement<Object>(_GetAllServicesPartnersRequest_QNAME, Object.class, null, value);
    }

}

演示

下面是如何使用根元素创建文档的示例get-all-services-partners-request.

package forum12990635;

import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance("forum12990635");

        Foo foo = new Foo();
        foo.setBar("Hello World");

        ObjectFactory objectFactory = new ObjectFactory();
        JAXBElement<Object> jaxbElement = objectFactory.createGetAllServicesPartnersRequest(foo);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(jaxbElement, System.out);
    }

}

产量

以下是运行演示代码的输出.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<get-all-services-partners-request xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="foo">
    <bar>Hello World</bar>
</get-all-services-partners-request>