The attribute required is undefined for the annotation type XmlElementRef
阿新 • • 發佈:2018-10-09
生成 bool target sta div val 方式 java 需要
異常描述: 幾天沒用的項目導進Eclipse中發現有異常 public class BooleanFeatureType extends FeatureBaseType{ @XmlElementRef(name = "Value", namespace = "http://schemas.sean.com/ma/CA/OPM/", type = JAXBElement.class, required = false) protected JAXBElement<Boolean> value; ...... @XmlElementRef那行報錯:The attribute required is undefined for the annotation type XmlElementRef 異常分析: 剛開始有點摸不到頭緒,因為這部分代碼是使用JAXB根據schema自動生成的,schema定義如下: <xsd:element name="BooleanFeature" type="BooleanFeatureType" minOccurs="0" maxOccurs="unbounded"> <xsd:annotation> <xsd:documentation>Boolean feature.</xsd:documentation> </xsd:annotation> </xsd:element> <xsd:complexType name="BooleanFeatureType"> <xsd:annotation> <xsd:documentation>Type for features with a boolean (true or false) value. </xsd:documentation> </xsd:annotation> <xsd:complexContent> <xsd:extension base="FeatureBaseType"> <xsd:sequence> <xsd:element name="Value" type="xsd:boolean" nillable="true" minOccurs="0"> <xsd:annotation> <xsd:documentation>The feature value, true or false.</xsd:documentation> </xsd:annotation> </xsd:element> </xsd:sequence> </xsd:extension> </xsd:complexContent> </xsd:complexType> 嘗試重新生成了一下,發現重新生成的代碼中沒有required屬性了 public class BooleanFeatureType extends FeatureBaseType{ @XmlElementRef(name = "Value", namespace = "http://schemas.sean.com/ma/CA/OPM/", type = JAXBElement.class) protected JAXBElement<Boolean> value; ...... 項目當前使用JDK1.6.0_45,於是看了下JDK1.6.0_45中XmlElementRef註解的定義 @Retention(RUNTIME) @Target({FIELD,METHOD}) public @interface XmlElementRef { Class type() default DEFAULT.class; String namespace() default ""; String name() default "##default"; static final class DEFAULT {} } 發現定義中根本沒有required屬性,換成JDK1.7.0_65之後,再看下XmlElementRef註解的定義 @Retention(RUNTIME) @Target({FIELD,METHOD}) public @interface XmlElementRef { Class type() default DEFAULT.class; String namespace() default ""; String name() default "##default"; static final class DEFAULT {} /** * Customize the element declaration to be required. * <p> * If required() is true, then Javabean property is mapped to * an XML schema element declaration with minOccurs="1". * maxOccurs is "1" for a single valued property and "unbounded" * for a multivalued property. * * <p> * If required() is false, then the Javabean property is mapped * to XML Schema element declaration with minOccurs="0". * maxOccurs is "1" for a single valued property and "unbounded" * for a multivalued property. * * <p> * For compatibility with JAXB 2.1, this property defaults to <tt>true</tt>, * despite the fact that {@link XmlElement#required()} defaults to false. * * @since 2.2 */ boolean required() default true; } 看來主要的原因是使用的JDK版本不同,註解的定義也是不同的 通過required屬性的註釋部分,可以確定required屬性是從JAXB 2.2開始添加到XmlElementRef註解定義中的 當然,JAXB 2.2的內容從JDK1.6開始,已經被添加到rt.jar中了 解決方式: 如果需要required屬性,可將JDK換為1.7,如果不需要,將JDK換為1.6的,再使用JAXB重新生成代碼即可 當然了,如果必須要用JDK1.6,而且需要支持required屬性,那麽JDK1.6 + jaxb-api(我使用的是jaxb-api-2.2.1.jar,僅僅加入jaxb-api-2.2.1.jar代碼便不會報錯了,但是如果想使用JAXB生成代碼,僅僅只有api是不夠的,還需要其它相關jar,比如:jaxb-impl-2.2.1.jar)也是可以滿足要求的
The attribute required is undefined for the annotation type XmlElementRef