我必须在REST Web服务中使用接口.这是接口Specs.java：

@XmlJavaTypeAdapter(MyAdapter.class)
public interface Specs {

    public BaseProperties getBaseProps();
    public void setBaseProps(BaseProperties baseProps);

}

MyAdapter.java：

public class MyAdapter extends XmlAdapter<Object,Object> 
{  
    public Object unmarshal(Object v) 
    { 
        return v; 
    }  
    public Object marshal(Object v) 
    { 
        return v; 
    }
}

RegSpecs.java

@XmlType
public class RegSpecs implements Specs{
private BaseProperties baseProps;

    public BaseProperties getBaseProps()
    {
        return baseProps;
    }
    public void setBaseProps(BaseProperties baseProps)
    {
        this.baseProps = baseProps;
    }

}

MapSpecs.java

@XmlType
public class MagSpecs implements Specs {

private BaseProperties baseProps;
private Features features;

    public BaseProperties getBaseProps()
    {
        return baseProps;
    }
    public void setBaseProps(BaseProperties baseProps)
    {
        this.baseProps = baseProps;
    }
    public Features getFeatures() {
        return features;
    }
    public void setFeatures(Features features) {
        this.features = features;
    }

}

访问此服务将引发以下错误：

javax.xml.bind.MarshalException
– with linked exception:
[javax.xml.bind.JAXBException: class entities.MagSpecs nor any of its super class is known to this context.]

如何修改我的上下文？我正在使用与Jersey 1.5捆绑在一起的JAXB

谢谢 ！

编辑：为了尝试更新我的上下文,我将此代码添加到我的客户端(资源)类中：

public class BookService  implements ContextResolver<JAXBContext> 
{

        private JAXBContext jaxbContext;

        public BookService() {
            try {
                // Bootstrap your JAXBContext will all necessary classes
                jaxbContext = JAXBContext.newInstance(Specs.class,MagSpecs.class, RegSpecs.class);
            } catch(Exception e) {
                throw new RuntimeException(e);
            }
        }

        public JAXBContext getContext(Class<?> clazz) {
            if(BookService.class == clazz) {
                return jaxbContext;
            }
            return null;
        }

在这种情况下,我会报错：

entities.Specs is an interface, and JAXB can’t handle interfaces.
this problem is related to the following location:
at entities.Specs
entities.Specs does not have a no-arg default constructor.
this problem is related to the following location:
at entities.Specs

解决方法:

Specs接口的客户端需要知道MagSpecs可以是它的一个实例,以便知道出于工具目的而查看它.最简单的方法是在Specs接口上放置@XmlSeeAlso批注：

@XmlSeeAlso({ MagSpecs.class, RegSpecs.class })
@XmlJavaTypeAdapter(MyAdapter.class) // Never needed this annotation myself...
public interface Specs {
    public BaseProperties getBaseProps();
    public void setBaseProps(BaseProperties baseProps);
}

通常,每当我使用JAXB批注时,都要确保编写大量测试以检查是否可以从所涉及的类生成XML模式,并从每个(合理的)入口点检查类和接口Web中的内容.我可以毫无例外地生成明智的模式.例如(为此,我为此感到抱歉)：

private SchemaOutputResolver sink;
StringWriter schema;

@Before
public void init() {
    schema = new StringWriter();
    sink = new SchemaOutputResolver() {
        @Override
        public Result createOutput(String namespaceUri,
                String suggestedFileName) throws IOException {
            StreamResult sr = new StreamResult(schema);
            sr.setSystemId("/dev/null");
            return sr;
        }
    };
    Assert.assertTrue(schema.toString().isEmpty());
}

private void testJAXB(Class<?>... classes) throws Exception {
    JAXBContext.newInstance(classes).generateSchema(sink);
    Assert.assertTrue(schema.toString().length() > 0);
}

@Test
public void testJAXBForSpecs() throws Exception {
    testJAXB(Specs.class);
}

[编辑]：您还需要将Specs接口更改为一个类,并使当前的实现继承自该类.如果需要,它可以是完全抽象的类.只要您没有在类中添加严肃的功能,它就应该起作用.