如何使用EclipseLink解組JSON數組MOXy JAXB提供者

Question

這看起來很簡單，但我必須缺少一些東西。我想要做的是解組一個JSON數組。我的代碼在JSON是一個簡單的對象時起作用，但是當我將它製作爲一個數組時（即使用[]繞着JSON環繞JSON），它就失敗了。以下是示例json，域類，解組代碼和異常。任何幫助將不勝感激。

樣品JSON： [{"CreateIndex":24988,"ModifyIndex":132476,"LockIndex":0,"Key":"Redirector","Flags":0} ]

域：

package eclipselink.example.moxy.json.simple.model; 

import javax.xml.bind.annotation.XmlAccessType; 
import javax.xml.bind.annotation.XmlAccessorType; 
import javax.xml.bind.annotation.XmlAttribute; 
import javax.xml.bind.annotation.XmlElement; 
import javax.xml.bind.annotation.XmlRootElement; 

import com.fasterxml.jackson.annotation.JsonIgnore; 
import com.fasterxml.jackson.annotation.JsonIgnoreProperties; 
import com.fasterxml.jackson.annotation.JsonProperty; 
import com.fasterxml.jackson.databind.annotation.JsonDeserialize; 
import com.fasterxml.jackson.databind.annotation.JsonSerialize; 
import com.google.common.base.Optional; 
import com.google.common.io.BaseEncoding; 
import com.orbitz.consul.model.kv.ImmutableValue; 
import com.orbitz.consul.util.UnsignedLongDeserializer; 

@org.immutables.value.Value.Immutable 
@JsonDeserialize(as = ImmutableValue.class) 
@JsonSerialize(as = ImmutableValue.class) 
@JsonIgnoreProperties(ignoreUnknown = true) 
@XmlRootElement 
@XmlAccessorType(XmlAccessType.FIELD) 
public class MyValue { 

    @XmlAttribute 
private long createIndex; 
    @XmlAttribute 
private long modifyIndex; 
    @XmlAttribute 
private long lockIndex; 
    @XmlAttribute 
private String key; 
    @XmlElement 
private long flags; 

    @XmlElement(nillable = true) 
private Optional<String> value; 
    @XmlElement 
private Optional<String> session; 


    @JsonProperty("CreateIndex") 
    public long getCreateIndex() { 
     return createIndex; 
    } 

    @JsonProperty("ModifyIndex") 
    public long getModifyIndex() { 
     return modifyIndex; 
    } 


    @JsonProperty("LockIndex") 
    public long getLockIndex() { 
     return lockIndex; 
    } 


    @JsonProperty("Key") 
    public String getKey() { 
     return key; 
    } 


    @JsonProperty("Flags") 
    @JsonDeserialize(using=UnsignedLongDeserializer.class) 
    public long getFlags() { 
     return flags; 
    } 

    @JsonProperty("Value") 
    public Optional<String> getValue() { 
     return value; 
    } 

    @JsonProperty("Session") 
    public Optional<String> getSession() { 
     return session; 
    } 

    @JsonIgnore 
    @org.immutables.value.Value.Lazy 
    public Optional<String> getValueAsString() { 

     if (getValue() != null && getValue().isPresent()) { 
      return Optional.of(
        new String(BaseEncoding.base64().decode(getValue().get())) 
      ); 
     } else { 
      return Optional.absent(); 
     } 

    } 
} 

和解組代碼：

public class Main_JSON_redirector { 

    private static final String INPUT_XML = "META-INF/input.xml"; 
    private static final String INPUT_JSON_URL = "http://192.168.85.186:8500/v1/kv/Redirector"; 
    private static final File INPUT_JSON_FILE = new File("C:/Users/dnance/EclipseLink-examples/moxy/json-simple/src/main/resources/META-INF/redirector.json"); 

    public static void main(String[] args) throws Exception { 
     System.out.println(); 
     System.out.println("Running EclipseLink MOXy Simple MAIN_JSON Example"); 

     Map<String, Object> properties = new HashMap<String, Object>(); 
     properties.put(JAXBContextProperties.JSON_WRAPPER_AS_ARRAY_NAME, true); 
     JAXBContext jc = JAXBContext.newInstance(new Class[] {MyValue.class}, properties); 

     Unmarshaller unmarshaller = jc.createUnmarshaller(); 
     unmarshaller.setProperty(UnmarshallerProperties.MEDIA_TYPE, MediaType.APPLICATION_JSON); 
     unmarshaller.setProperty(UnmarshallerProperties.JSON_INCLUDE_ROOT, false); 

     StreamSource source = new StreamSource(INPUT_JSON_FILE); 
     JAXBElement<MyValue[]> jaxbElement = unmarshaller.unmarshal(source, MyValue[].class); 
MyValue[] value = jaxbElement.getValue(); 
System.out.println("value: " + value[0].getValueAsString()); 
... 

例外：

Running EclipseLink MOXy Simple MAIN_JSON Example 
Exception in thread "main" javax.xml.bind.UnmarshalException 
- with linked exception: 
[Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.XMLMarshalException 
Exception Description: A descriptor for class [Leclipselink.example.moxy.json.simple.model.MyValue; was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.] 
    at org.eclipse.persistence.jaxb.JAXBUnmarshaller.handleXMLMarshalException(JAXBUnmarshaller.java:1072) 
    at org.eclipse.persistence.jaxb.JAXBUnmarshaller.unmarshal(JAXBUnmarshaller.java:341) 
    at eclipselink.example.moxy.json.simple.Main_JSON_redirector.main(Main_JSON_redirector.java:58) 
Caused by: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070): org.eclipse.persistence.exceptions.XMLMarshalException 
Exception Description: A descriptor for class [Leclipselink.example.moxy.json.simple.model.MyValue; was not found in the project. For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter. 
    at org.eclipse.persistence.exceptions.XMLMarshalException.descriptorNotFoundInProject(XMLMarshalException.java:154) 
    at org.eclipse.persistence.internal.oxm.Context$ContextState.getSession(Context.java:137) 
    at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:798) 
    at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:1) 
    at org.eclipse.persistence.internal.oxm.Context.getSession(Context.java:458) 
    at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:366) 
    at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:1) 
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:837) 
    at org.eclipse.persistence.internal.oxm.record.SAXUnmarshaller.unmarshal(SAXUnmarshaller.java:710) 
    at org.eclipse.persistence.internal.oxm.XMLUnmarshaller.unmarshal(XMLUnmarshaller.java:643) 
    at org.eclipse.persistence.jaxb.JAXBUnmarshaller.unmarshal(JAXBUnmarshaller.java:339) 

Answer 1

你只需要在unmarshal方法中指定類型類而不是數組類，例如。

Collection<MyValue> myValues = (Collection<MyValue>) unmarshaller.unmarshal(source, MyValue.class).getValue(); 

既然你有unmarshaller.setProperty(UnmarshallerProperties.JSON_INCLUDE_ROOT, false);它只是工作。沒有它unmarshal返回JAXBElement<Collection<JAXBElement>>。