java - 如何转换 moxy json 输出？

Question

我正在尝试做与 Can I get MOXy to convert a string to a boolean when generating json 几乎相同的事情.

我从 xml -> 对象开始。对象现在包含我想要输出为 GeoJson 的几何图形。

我尝试在 xml-bindings.xml 中添加 xml-java-type-adapters，但它们似乎从未运行。 package-info.java 中的注释会运行，但也会影响 xml-> object，而不仅仅是 object->json。这就是为什么我认为 xml 映射覆盖是个好主意。

现在我有

<?xml version="1.0" encoding="UTF-8"?>
<xml-bindings package-name="se.lantmateriet.geoaccess.outrettfastighetsomrade.jaxb" xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.eclipse.org/eclipselink/xsds/persistence/oxm http://www.eclipse.org/eclipselink/xsds/eclipselink_oxm_2_4.xsd" version="2.4">
<java-types>
    <java-type name="OutrettFastighetsomradeReferensType">
        <java-attributes>
            <xml-element java-attribute="centralpunkt">
                <xml-java-type-adapter value="se.lantmateriet.sercxi.web.controller.GeoJsonAdapter"/>
            </xml-element>
        </java-attributes>
    </java-type>
</java-types>    

和一些演示代码:

    List<OutrettFastighetsomradeReferensType> result = this.outrettFastighetsomradeReferensRepository
        .getByExternIdStartsWith(decodeUtf8String(externId));

    List<InputStream> metadata = Lists.newArrayList(new ClassPathResource("json-bindings.xml").getInputStream());

    Map<String, List<InputStream>> properties = ImmutableMap.of(JAXBContextProperties.OXM_METADATA_SOURCE, metadata);

    Jaxb2Marshaller jaxb2Marshaller = new Jaxb2Marshaller();
    jaxb2Marshaller.setLazyInit(true);
    jaxb2Marshaller.setContextPaths("se.lantmateriet.sercxi.gateway.outrettfastighetsomrade.config", "se.lantmateriet.geoaccess.jaxb.gml",
        "se.lantmateriet.geoaccess.outrettfastighetsomrade.jaxb");
    jaxb2Marshaller.setJaxbContextProperties(properties);

    jaxb2Marshaller.afterPropertiesSet();

    StringResult stringResult = new StringResult();

    Marshaller marshaller = jaxb2Marshaller.getJaxbContext().createMarshaller();

    marshaller.setProperty("eclipselink.media-type", MediaType.APPLICATION_JSON_VALUE);

    marshaller.marshal(result.get(0), stringResult);

    return stringResult.toString();

XML适配器:

public class GeoJsonAdapter extends XmlAdapter<PointPropertyType, Map<String, Object>> {

@Override
public Map<String, Object> unmarshal(final PointPropertyType v) throws Exception {
    return JTSGeometryToGeoJsonConverter.convertGeometryToJson(POSITION(N(v.getPoint().getPos().getValue().get(0)),
        E(v.getPoint().getPos().getValue().get(1))).toPoint());
}

@Override
public PointPropertyType marshal(final Map<String, Object> v) throws Exception {
    throw new UnsupportedOperationException();
}

}

以及我想要在 json 输出中转换的属性centralpunkt的域对象(我在第三方 jar 中有此代码，无法更改它):

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "OutrettFastighetsomradeReferensType", namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", propOrder = {
"objektidentitet",
"fodelsenummer",
"externId",
"fastighetsomradetyp",
"centralpunkt"
})
public class OutrettFastighetsomradeReferensType {

@XmlElement(namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", required = true)
protected String objektidentitet;
@XmlElement(namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", required = true)
protected String fodelsenummer;
@XmlElement(namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", required = true)
protected String externId;
@XmlElement(namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", required = true)
protected FastighetsomradeTypType fastighetsomradetyp;
@XmlElement(name = "Centralpunkt", namespace = "http://namespace.lantmateriet.se/distribution/produkter/outrettfastighetsomrade/v1", required = true)
protected PointPropertyType centralpunkt;

但它不起作用:-(

Caused by: javax.xml.bind.JAXBException - with linked exception:
[java.lang.NullPointerException]
at org.eclipse.persistence.jaxb.JAXBContext$ContextPathInput.createContextState(JAXBContext.java:915)
at org.eclipse.persistence.jaxb.JAXBContext$ContextPathInput.createContextState(JAXBContext.java:848)
at org.eclipse.persistence.jaxb.JAXBContext.<init>(JAXBContext.java:182)
at org.eclipse.persistence.jaxb.JAXBContextFactory.createContext(JAXBContextFactory.java:129)
at sun.reflect.GeneratedMethodAccessor43.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:137)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:108)
at javax.xml.bind.ContextFinder.find(ContextFinder.java:258)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:412)
at org.springframework.oxm.jaxb.Jaxb2Marshaller.createJaxbContextFromContextPath(Jaxb2Marshaller.java:470)
at org.springframework.oxm.jaxb.Jaxb2Marshaller.getJaxbContext(Jaxb2Marshaller.java:443)
... 73 more
Caused by: java.lang.NullPointerException
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.updateGlobalElements(AnnotationsProcessor.java:3868)
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.postBuildTypeInfo(AnnotationsProcessor.java:735)
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.buildNewTypeInfo(AnnotationsProcessor.java:4746)
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.processReferencedClass(AnnotationsProcessor.java:838)
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.buildTypeInfo(AnnotationsProcessor.java:812)
at org.eclipse.persistence.jaxb.compiler.AnnotationsProcessor.postBuildTypeInfo(AnnotationsProcessor.java:734)
at org.eclipse.persistence.jaxb.compiler.XMLProcessor.processXML(XMLProcessor.java:364)
at org.eclipse.persistence.jaxb.compiler.Generator.<init>(Generator.java:104)
at org.eclipse.persistence.jaxb.JAXBContext$ContextPathInput.createContextState(JAXBContext.java:912)
... 85 more

有什么想法吗？

这就是我真正想要的:

<?xml version="1.0" encoding="UTF-8"?>
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.eclipse.org/eclipselink/xsds/persistence/oxm http://www.eclipse.org/eclipselink/xsds/eclipselink_oxm_2_4.xsd" version="2.4">
<xml-java-type-adapters>
    <xml-java-type-adapter value="se.lantmateriet.sercxi.web.controller.GeoJsonAdapter" type="se.lantmateriet.geoaccess.jaxb.gml.PointPropertyType"/>
</xml-java-type-adapters>

但这似乎并没有影响任何事情。全局级别的 xml-java-type-adapter 似乎没有记录？

谢谢

/马格努斯

Answer 1

目前存在一些问题。以下是我第一次尝试回答:

<小时/>

创建XmlAdapter

由于您尝试调整 PointPropertyType 类，因此您的 XmlAdapter 向后。而不是这个。

public class GeoJsonAdapter extends XmlAdapter<PointPropertyType, Map<String, Object>> {

你应该有:

public class GeoJsonAdapter extends XmlAdapter<Map<String, Object>, PointPropertyType> {

<小时/>

映射为 XmlAdapter

的值类型

目前，在 XmlAdapter 中使用 Map 作为值类型存在问题(见下文)。现在您应该使用常规 POJO。

• http://bugs.eclipse.org/421680

<小时/>

指定包级适配器

MOXy 元数据 (json-bindings.xml)

当您通过 JAXB 注释或 MOXy 的元数据文档在包级别指定 XmlAdapter 时，它将应用于属于该包中的类的所有映射字段/属性。在下面的示例文档中，se.lantmateriet.sercxi.web.controller.GeoJsonAdapter XmlAdapter 将应用于 se.lantmateriet.geoaccess.jaxb.gml.PointPropertyType 类型的字段/属性 属于 forum19952922 包中的类。

<?xml version="1.0" encoding="UTF-8"?>
<xml-bindings 
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.eclipse.org/eclipselink/xsds/persistence/oxm http://www.eclipse.org/eclipselink/xsds/eclipselink_oxm_2_4.xsd" 
    version="2.4"
    package-name="forum19952922">
        <xml-java-type-adapters>
            <xml-java-type-adapter value="se.lantmateriet.sercxi.web.controller.GeoJsonAdapter" type="se.lantmateriet.geoaccess.jaxb.gml.PointPropertyType" />
        </xml-java-type-adapters>
</xml-bindings>

了解更多信息

• http://blog.bdoughan.com/2012/02/jaxb-and-package-level-xmladapters.html

<小时/>

简化 Bootstrap

下面是一个代码示例，将有助于简化您的引导过程。如果以 String 形式给出的位置与将加载该文件的相对文件位置匹配，否则该位置将被尝试作为类路径上的资源。

    Map<String, Object> properties = new HashMap<String, Object>(2);
    properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, "forum19952922/json-bindings.xml");
    properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
    JAXBContext jc = JAXBContext.newInstance(new Class[] {Root.class}, properties);