java 为什么JAXB会说“xxx是接口，而JAXB不能处理接口”。即使生成的类不是接口
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Why does JAXB say "xxx is an interface, and JAXB can't handle interfaces". Even though the generated class is not an interface
提问by Alok Chandna
I used JAXB to bind my xsd's and then tried creating the JAXBContext:
我使用 JAXB 来绑定我的 xsd，然后尝试创建 JAXBContext：
JAXBContext jaxbContext = JAXBContext.newInstance("my package name");
But JAXB gives 180 IllegalAnnotationsException.
但是 JAXB 给出了 180 IllegalAnnotationsException。
Most of the exceptions have the following messages:
大多数异常都有以下消息：
- XXX is an interface, and JAXB can't handle interfaces
- XXX does not have a no-arg default constructor
- @XmlAttribute/@XmlValue need to reference a Java type that maps to text in XML.
- XXX是接口，JAXB不能处理接口
- XXX 没有无参数的默认构造函数
- @XmlAttribute/@XmlValue 需要引用映射到 XML 文本的 Java 类型。
When I look at the classes generated none of them are interfaces and I can't understand why JAXB is interpreting them as interfaces.
当我查看生成的类时，它们都不是接口，我不明白为什么 JAXB 将它们解释为接口。
Here's is the stack trace of one of the errors reported by JAXB :
这是 JAXB 报告的错误之一的堆栈跟踪：
com.sc.md.datatypes.schemas.csemessage.EnvelopeType is an interface, and JAXB can't handle interfaces.
this problem is related to the following location:
at com.sc.md.datatypes.schemas.csemessage.EnvelopeType
at protected com.sc.md.datatypes.schemas.csemessage.EnvelopeType com.sc.md.datatypes.schemas.csemessage.cseMessage.envelope
at com.sc.md.datatypes.schemas.csemessage.cseMessage
com.sc.md.datatypes.schemas.csemessage.EnvelopeType does not have a no-arg default constructor.
this problem is related to the following location:
at com.sc.md.datatypes.schemas.csemessage.EnvelopeType
at protected com.sc.md.datatypes.schemas.csemessage.EnvelopeType com.sc.md.datatypes.schemas.csemessage.cseMessage.envelope
at com.sc.md.datatypes.schemas.csemessage.cseMessage
And this is how the type is defined in xsd :
这是在 xsd 中定义类型的方式：
<xs:complexType name="EnvelopeType">
<xs:sequence>
<xs:element name="Sent" type="DateTimeType"/>
<xs:element name="Identifier" type="String_1_14"/>
<xs:element name="AcknowledgementCode" type="AcknowledgementCodeType"/>
</xs:sequence>
<xs:simpleType name="AcknowledgementCodeType">
<xs:restriction base="xs:string">
<xs:enumeration value="m"/>
<xs:enumeration value="p"/>
</xs:restriction>
</xs:simpleType>
Here is the pom.xml I have used to generate the binding :
这是我用来生成绑定的 pom.xml：
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.cs</groupId>
<artifactId>cs-jaxb</artifactId>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>com.sun.xml.bind</groupId>
<artifactId>jaxb-impl</artifactId>
<version>2.2.4-1</version>
</dependency>
</dependencies>
<name>cs jaxb</name>
<version>1.0.0</version>
<parent>
<artifactId>hip-jaxb-parent</artifactId>
<groupId>com.cs</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<build>
<defaultGoal>install</defaultGoal>
<plugins>
<plugin>
<groupId>org.jvnet.jaxb2.maven2</groupId>
<artifactId>maven-jaxb2-plugin</artifactId>
<version>0.8.0</version>
<executions>
<execution>
<id>CS</id>
<goals>
<goal>generate</goal>
</goals>
<configuration>
<schemaDirectory>src/main/resources/</schemaDirectory>
<schemaIncludes>
<include>**/*.xsd</include>
</schemaIncludes>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<inherited>true</inherited>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
Please be patient with me since its the first time I'm asking a question on the web :)
请耐心等待，因为这是我第一次在网上提问:)
回答by Alok Chandna
Thanks to all, it was as usual a big mistake on my part, but anyways I enjoyed using stackoverflow for the first time and will make a point to snoop around here.
多亏了所有人，这对我来说和往常一样是一个大错误，但无论如何我第一次喜欢使用 stackoverflow 并且会在这里窥探一下。
The problem was with my classpath.I was referring to a xmlbeans binding project, which had the java source with the same package and classes as the ones generated by jaxb, which were included as a jar on my classpath. So I had 2 classes with same name and package, but to my misery JAXB was picking the Xmlbeans class and I didn't realise that for 2 days.This is one of the oldest errors in Java and I apologise for the blunder.If anyone needs any clarification please drop a comment.
问题出在我的类路径上。我指的是一个 xmlbeans 绑定项目，它的 java 源与 jaxb 生成的包和类具有相同的包和类，这些包和类作为 jar 包含在我的类路径中。所以我有 2 个具有相同名称和包的类，但让我痛苦的是 JAXB 选择了 Xmlbeans 类，我两天没有意识到这一点。这是 Java 中最古老的错误之一，我为这个错误道歉。如果有人需要任何说明，请发表评论。
回答by Robert
Have you annotated all root classes with the @XmlRootElementannotation?
您是否使用注释对所有根类进行了@XmlRootElement注释？
See: Unofficial JAXB Guide - Mapping interfaces - Java.net
请参阅：非官方 JAXB 指南 - 映射接口 - Java.net
Second, I would recommend you not to create your JAXBContext via JAXBContext.newInstance("my package name");. It is better to specify the root classes explicitly. Therefore if you have two root classes named ClassAand ClassBuse it this way:
其次，我建议您不要通过JAXBContext.newInstance("my package name");. 最好明确指定根类。因此，如果您有两个根类命名ClassA并ClassB以这种方式使用它：
JAXBContext.newInstance(new Class[] {ClassA.class, ClassB.class});
回答by bdoughan
I suspect that you are trying to use a JAXB 1 (JSR-31) model with a JAXB 2 (JSR-222) runtime. In JAXB 1 implementations generated spec defined interfaces backed by implementation specific impl clases. In JAXB 2 this became spec defined classes with standard annotations that are compatible with all implementations. Most JAXB 2 implementations support their own JAXB 1 models, but some additional config may be necessary, if you try to use a JAXB 1 model with a difference JAXB 2 provider you may see this type of error.
我怀疑您正在尝试将 JAXB 1 ( JSR-31) 模型与 JAXB 2 ( JSR-222) 运行时一起使用。在 JAXB 1 实现中，生成的规范定义的接口由实现特定的 impl 类支持。在 JAXB 2 中，这成为规范定义的类，带有与所有实现兼容的标准注释。大多数 JAXB 2 实现都支持它们自己的 JAXB 1 模型，但可能需要一些额外的配置，如果您尝试使用具有不同 JAXB 2 提供程序的 JAXB 1 模型，您可能会看到此类错误。
