Jersey 2枚舉作為方法參數拋出異常

Question

我目前正在將jersey 1.x項目遷移到2.4.1，並在使用枚舉作為參數（PathParam，QueryParam等）時出錯。 基本上這個枚舉應該是基於球衣對方法參數的第三個要求

有一個名為valueOf或fromString的靜態方法接受單個String參數（例如，參見Integer.valueOf（String）和java.util.UUID.fromString（String））;

由於這個項目使用xsd作為契約來生成java類，我有：

<xs:simpleType name="status">
    <xs:restriction base="xs:string">
        <xs:enumeration value="ACTIVE" />
        <xs:enumeration value="INACTIVE" />
    </xs:restriction>
</xs:simpleType>

產生：

@XmlType(name = "status")
@XmlEnum
public enum Status {

    ACTIVE,
    INACTIVE;

    public String value() {
        return name();
    }

    public static Status fromValue(String v) {
        return valueOf(v);
    }

}

當它用於：

@GET
public Response search(@QueryParam("status") my.package.Status status) {
//..other code here
}

它產生：

org.glassfish.jersey.server.internal.inject.ExtractorException: Error unmarshalling JAXB object of type "class my.package.Status".
    at org.glassfish.jersey.server.internal.inject.JaxbStringReaderProvider$RootElementProvider$1.fromString(JaxbStringReaderProvider.java:195)
    at org.glassfish.jersey.server.internal.inject.AbstractParamValueExtractor.convert(AbstractParamValueExtractor.java:138)
    at org.glassfish.jersey.server.internal.inject.AbstractParamValueExtractor.fromString(AbstractParamValueExtractor.java:129)
    at org.glassfish.jersey.server.internal.inject.SingleValueExtractor.extract(SingleValueExtractor.java:83)
    at org.glassfish.jersey.server.internal.inject.QueryParamValueFactoryProvider$QueryParamValueFactory.provide(QueryParamValueFactoryProvider.java:88)
    at org.glassfish.jersey.server.spi.internal.ParameterValueHelper.getParameterValues(ParameterValueHelper.java:81)
    at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$AbstractMethodParamInvoker.getParamValues(JavaResourceMethodDispatcherProvider.java:121)
    at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:152)
    at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:104)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:367)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:349)
    at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:106)
    at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:259)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:318)
    at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
    at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:983)
    at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:361)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:372)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:335)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:218)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:401)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
    at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
    at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: javax.xml.bind.UnmarshalException
 - with linked exception:
[org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog.]
    at javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException(AbstractUnmarshallerImpl.java:335)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.createUnmarshalException(UnmarshallerImpl.java:512)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:209)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:181)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:232)
    at org.glassfish.jersey.server.internal.inject.JaxbStringReaderProvider$RootElementProvider$1.fromString(JaxbStringReaderProvider.java:192)
    ... 41 more
Caused by: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog.
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:441)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368)
    at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1388)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:998)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:489)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
    at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
    at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
    at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:203)
    ... 44 more

因為它是在JaxbStringReaderProvider的解組期間觸發的，所以當我生成的類沒有xml注釋時就不應該這樣。 處理枚舉類型方法參數的最佳方法是什么，而不是為每個需要的枚舉類型創建一個包含字符串構造函數的包裝器對象？

Answer 1

您應該實現自定義ParamConverterProvider和ParamConverter，並將您的實現注冊到JAX-RS運行時（使用JAX-RS Application或web.xml ）。 就像是：

@Provider
public class GeneratedEnumParamConverterProvider implements ParamConverterProvider {

    @Override
    public <T> ParamConverter<T> getConverter(final Class<T> rawType, final Type genericType,
                                              final Annotation[] annotations) {
        try {
            final Method fromValueMethod = rawType.getMethod("fromValue", String.class);

            return new ParamConverter<T>() {
                @Override
                public T fromString(final String value) {
                    try {
                        return rawType.cast(fromValueMethod.invoke(null, value));
                    } catch (Exception e) {
                        throw new IllegalArgumentException("Given value (" + value + ") cannot be converted to parameter of type" + rawType);
                    }
                }

                @Override
                public String toString(final T value) {
                    return value.toString();
                }
            };
        } catch (Exception e) {
            return null;
        }
    }
}

Answer 2

在org.eclipse.persistence.jaxb.JAXBContext中以這種方式啟動DEFAULT_VALIDATION_EVENT_HANDER：

 protected static final ValidationEventHandler DEFAULT_VALIDATION_EVENT_HANDER = new ValidationEventHandler() {
     public boolean handleEvent(ValidationEvent event) {
         return event.getSeverity() < ValidationEvent.FATAL_ERROR;
     }
 };

它將級別提升到致命錯誤，我認為應該是錯誤的。 所以上面的代碼可以是：

 protected static final ValidationEventHandler DEFAULT_VALIDATION_EVENT_HANDER = new DefaultValidationEventHandler();

我在創建服務器時使用了反射來修改DEFAULT_VALIDATION_EVENT_HANDER，然后在遇到錯誤的枚舉字符串值時會拋出異常。

在JAXBContext中修改DEFAULT_VALIDATION_EVENT_HANDER的代碼：

    final Field field = JAXBContext.class.getDeclaredField("DEFAULT_VALIDATION_EVENT_HANDER");
    field.setAccessible(true);

    Field modifiersField = Field.class.getDeclaredField("modifiers");
    modifiersField.setAccessible(true);
    modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
    field.set(null, new DefaultValidationEventHandler());