Java JsonMappingException 错误

Question

我已经使用 jersey 在 java 中编写了一个 REST API。当我使用 XML 请求时，一切正常，但当我使用 JSON 请求时，我总是得到 JsonMappingException。

这些对象是使用来自 xsd 文件的 Jaxb 生成的。由于 XML 请求有效，我假设这些生成的对象是正确的。

谁能告诉我我错过了什么？

(在底部您可以找到错误消息、WS、对象和示例的 xsd)

提前致谢。

错误:

[#|2012-12-04T18:55:56.599+0100|WARNING|glassfish3.1.2|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=29;_ThreadName=Thread-2;|StandardWrapperValve[ServletAdaptor]: PWC1406: Servlet.service() for servlet ServletAdaptor threw exception
org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type [simple type, class javax.xml.bind.JAXBElement<be.api.schema.sensorrequest.SensorCreateRequest>]: can not instantiate from JSON object (need to add/enable type information?)
 at [Source: org.apache.catalina.connector.CoyoteInputStream@20a49a63; line: 2, column: 1]
        at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
        at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObjectUsingNonDefault(BeanDeserializer.java:740)
        at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:683)
        at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
        at org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:2695)
        at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1308)
        at org.codehaus.jackson.jaxrs.JacksonJsonProvider.readFrom(JacksonJsonProvider.java:419)
        at com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy.readFrom(JacksonProviderProxy.java:139)
        at com.sun.jersey.spi.container.ContainerRequest.getEntity(ContainerRequest.java:474)
        at com.sun.jersey.server.impl.model.method.dispatch.EntityParamDispatchProvider$EntityInjectable.getValue(EntityParamDispatchProvider.java:123)
        at com.sun.jersey.server.impl.inject.InjectableValuesProvider.getInjectableValues(InjectableValuesProvider.java:46)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$EntityParamInInvoker.getParams(AbstractResourceMethodDispatchProvider.java:153)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:183)
        at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
        at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
        at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
        at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
        at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
        at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1550)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
        at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
        at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
        at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:331)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
        at com.sun.enterprise.v3.services.impl.ContainerMapper$AdapterCallable.call(ContainerMapper.java:317)
        at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:195)
        at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:860)
        at com.sun.grizzly.http.ajp.AjpProcessorTask.invokeAdapter(AjpProcessorTask.java:135)
        at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:757)
        at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1056)
        at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:229)
        at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
        at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
        at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
        at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
        at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
        at java.lang.Thread.run(Thread.java:662)
|#]

WS 实现:

@POST
    @Consumes(
    {
        MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON
    })
    @Produces(
    {
        MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON
    })
    @Validation(requestObject = SensorCreateRequest.class, xsd = "SensorRequest.xsd")
    public SensorCreateResponse post(@TypeHint(SensorCreateRequest.class) JAXBElement<SensorCreateRequest> JAXBSensorCreateRequest,
                                     @HeaderParam(value = "client") String clientName,
                                     @HeaderParam(value = "session") String sessionToken) throws WebApplicationException
    {

    }

请求对象(SensorCreateRequest)

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "SensorCreateRequestType", propOrder = {

})
@XmlRootElement(name = "sensorCreateRequest")
public class SensorCreateRequest implements Serializable, Equals, HashCode, ToString
{

    @XmlElement(namespace = "http://www.api.be/schema/Sensor", required = true)
    protected Sensors sensors;

    /**
     * Default no-arg constructor
     * 
     */
    public SensorCreateRequest() {
        super();
    }

    /**
     * Fully-initialising value constructor
     * 
     */
    public SensorCreateRequest(final Sensors sensors) {
        this.sensors = sensors;
    }

    //Getters, Setters, toString, hash & equals

}

传感器对象:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "SensorsType", propOrder = {
    "sensors"
})
@XmlRootElement(name = "sensors")
public class Sensors implements Serializable, Equals, HashCode, ToString
{

    @XmlElement(name = "sensor")
    protected List<Sensor> sensors;

    /**
     * Default no-arg constructor
     * 
     */
    public Sensors() {
        super();
    }

    /**
     * Fully-initialising value constructor
     * 
     */
    public Sensors(final List<Sensor> sensors) {
        this.sensors = sensors;
    }

    //Getters, Setters, toString, hash & equals

}

传感器对象:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "SensorType", propOrder = {
    "sensorId",
    "name",
    "token",
    "groups",
    "locations",
    "dataProfile",
    "status",
    "first",
    "last",
    "lastValue",
    "longName",
    "circles"
})
@XmlRootElement(name = "sensor")
public class Sensor implements Serializable, Equals, HashCode, ToString
{

    protected int sensorId;
    @XmlElement(required = true)
    protected String name;

    /**
     * Default no-arg constructor
     * 
     */
    public Sensor() {
        super();
    }

    /**
     * Fully-initialising value constructor
     * 
     */
    public Sensor(final int sensorId, final String name) {
        this.sensorId = sensorId;
        this.name = name;
    }

    //Getters, Setters, toString, hash & equals

}

SensorRequest xsd:

<?xml version="1.0" encoding="UTF-8"?>

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
        targetNamespace="http://www.api.be/schema/SensorRequest"
        xmlns:tns="http://www.api.be/schema/SensorRequest"
        xmlns:s="http://www.api.be/schema/Sensor"
        elementFormDefault="qualified">

    <xsd:import namespace="http://www.api.be/schema/Sensor" schemaLocation="Sensor.xsd"/>

    <xsd:element name="sensorCreateRequest" type="tns:SensorCreateRequestType"/>

    <xsd:complexType name="SensorCreateRequestType">
        <xsd:all>
            <xsd:element ref="s:sensors" minOccurs="1" maxOccurs="1" />
        </xsd:all>
    </xsd:complexType>

</xsd:schema>

传感器 xsd:

<?xml version="1.0" encoding="UTF-8"?>

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="http://www.api.be/schema/Sensor"
            xmlns:tns="http://www.api.be/schema/Sensor"
            elementFormDefault="qualified">

    <!-- Sensor -->
    <xsd:element name="sensors" type="tns:SensorsType"/>

    <xsd:complexType name="SensorsType">
        <xsd:sequence>
            <xsd:element name="sensor" type="tns:SensorType" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:element name="sensor" type="tns:SensorType" />

    <!-- Sensors -->
    <xsd:complexType name="SensorType">
        <xsd:sequence>
            <xsd:element name="sensorId" type="xsd:int" minOccurs="1" maxOccurs="1"/>
            <xsd:element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:schema>

Answer 1

注意:我是 EclipseLink JAXB (MOXy) JAXB (JSR-222) 的领导和成员专家组。

JAXB (JSR-222) 规范没有说明任何关于 JSON 绑定(bind)的内容。 JAX-RS 提供者利用的几个 JSON-Binding 实现能够从 JAXB 注释中派生出 JSON 表示。在您的环境中，您正在使用 Jackson . Jackson 支持 JAXB 元数据的子集，目前不支持 JAXBElement 类。请参阅 Jackson 领导的以下回答:

• JACKSON support for Java Generics?

EclipseLink JAXB (MOXy) 为我们的 JSON 绑定(bind)实现中的所有 JAXB 结构提供支持，它可能更适合您的用例:

• http://blog.bdoughan.com/2012/05/moxy-as-your-jax-rs-json-provider.html

下面是一些使用 MOXy 作为 JSON 提供程序的 Jersey 官方示例的链接:

• https://github.com/jersey/jersey/blob/master/examples/json-moxy/README.html