XmlElements (Java EE 5 SDK)

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Java EE 5 SDK

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摘要: REQUIRED | OPTIONAL

详细信息: ELEMENT

javax.xml.bind.annotation Annotation Type XmlElements

@Retention(value=RUNTIME) @Target(value={FIELD,METHOD}) public @interface XmlElements

A container for multiple @XmlElement annotations. Multiple annotations of the same type are not allowed on a program element. This annotation therefore serves as a container annotation for multiple @XmlElements as follows:

 @XmlElements({ @XmlElement(...),@XmlElement(...) })

The @XmlElements annnotation can be used with the following program elements:

a JavaBean property
non static, non transient field

This annotation is intended for annotation a JavaBean collection property (e.g. List).

Usage

The usage is subject to the following constraints:

This annotation can be used with the following annotations: @XmlIDREF, @XmlElementWrapper.
If @XmlIDREF is also specified on the JavaBean property, then each @XmlElement.type() must contain a JavaBean property annotated with @XmlID.

See "Package Specification" in javax.xml.bind.package javadoc for additional common information.

Example 1: Map to a list of elements

    
    // Mapped code fragment
    public class Foo {
        @XmlElements(
            @XmlElement(name="A", type=Integer.class),
            @XmlElement(name="B", type=Float.class)
         }
         public List items;
    }

    <!-- XML Representation for a List of {1,2.5} 
            XML output is not wrapped using another element -->
    ...
     1 
     2.5 
    ...

    <!-- XML Schema fragment -->
    <xs:complexType name="Foo">
      <xs:sequence>
        <xs:choice minOccurs="0" maxOccurs="unbounded">
          <xs:element name="A" type="xs:int"/>
          <xs:element name="B" type="xs:float"/>
        <xs:choice>
      </xs:sequence>
    </xs:complexType>

Example 2: Map to a list of elements wrapped with another element

 
    // Mapped code fragment
    public class Foo {
        @XmlElementWrapper(name="bar")
        @XmlElements(
            @XmlElement(name="A", type=Integer.class),
            @XmlElement(name="B", type=Float.class)
        }
        public List items;
    }

    <!-- XML Schema fragment -->
    <xs:complexType name="Foo">
      <xs:sequence>
        <xs:element name="bar">
          <xs:complexType>
            <xs:choice minOccurs="0" maxOccurs="unbounded">
              <xs:element name="A" type="xs:int"/>
              <xs:element name="B" type="xs:float"/>
            </xs:choice>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>

Example 3: Change element name based on type using an adapter.

    class Foo {
       @XmlJavaTypeAdapter(QtoPAdapter.class)
       @XmlElements({
           @XmlElement(name="A",type=PX.class),
           @XmlElement(name="B",type=PY.class)
       })
       Q bar;
    }
 
    @XmlType abstract class P {...}
    @XmlType(name="PX") class PX extends P {...}
    @XmlType(name="PY") class PY extends P {...}

    <!-- XML Schema fragment -->
    <xs:complexType name="Foo">
      <xs:sequence>
        <xs:element name="bar">
          <xs:complexType>
            <xs:choice minOccurs="0" maxOccurs="unbounded">
              <xs:element name="A" type="PX"/>
              <xs:element name="B" type="PY"/>
            </xs:choice>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>

从以下版本开始:

JAXB2.0

作者: