Restful Web服务找不到Java类和Java类型类以及MIME媒体类型application / xml的消息正文编写器

Question

我有一个rest ful web服务，它将通过hibernate从数据库中获取某些值 并将使用seeter和getter设置这些值。我能够查看值，但在尝试使用Web服务时，我得到了异常 “未找到Java类和Java类型类以及MIME媒体类型application / xml的消息正文编写器”

我的网络服务代码是

@Path("/IFConfig")
public class IFconfigService {
    private static final String FILE_PATH = "C:\\Users\\298637\\Desktop\\sample.xml";
    @GET
    @Path("/get/{varX}")
    @Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON })
    public IfMainbo  Webserviceoutput(@PathParam("varX") String varX)
    {

        List iFObjects = new ArrayList();
        String iFName=varX;
        System.out.println("the parameter name is "+iFName);
        IfMainbo ifMainbo = new IfMainbo();
        IfMain ifMain = new IfMain();
        FetchConfiguration passing = new FetchConfiguration();
        iFObjects = passing.loadConfigData(iFName);
        System.out.println("OBJECT SIZE"+iFObjects.size());
        for (Iterator iterator = iFObjects.iterator(); iterator.hasNext();){
            ifMain = (IfMain)iterator.next();
    }
        ifMainbo.setIfId(ifMain.getIfId());
        ifMainbo.setIfName(ifMain.getIfName());
        System.out.println(ifMainbo.getIfId());
        System.out.println(ifMainbo.getIfName());
        return ifMainbo;
}
}

我的提供类或setter和getter类代码是

@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "ifMainbo", propOrder = {
    "entities",
    "ifId",
    "ifName"
})
public  class IfMainbo implements MessageBodyWriter{

    @XmlElement(required = true, nillable = true)
    protected List<Object> entities;
    protected String ifId;
    protected String ifName;

    /**
     * Gets the value of the entities property.
     * 
     * <p>
     * This accessor method returns a reference to the live list,
     * not a snapshot. Therefore any modification you make to the
     * returned list will be present inside the JAXB object.
     * This is why there is not a <CODE>set</CODE> method for the entities property.
     * 
     * <p>
     * For example, to add a new item, do as follows:
     * <pre>
     *    getEntities().add(newItem);
     * </pre>
     * 
     * 
     * <p>
     * Objects of the following type(s) are allowed in the list
     * {@link Object }
     * 
     * 
     */
    public List<Object> getEntities() {
        if (entities == null) {
            entities = new ArrayList<Object>();
        }
        return this.entities;
    }

    /**
     * Gets the value of the ifId property.
     * 
     * @return
     *     possible object is
     *     {@link String }
     *     
     */
    public String getIfId() {
        return ifId;
    }

    /**
     * Sets the value of the ifId property.
     * 
     * @param value
     *     allowed object is
     *     {@link String }
     *     
     */
    public void setIfId(String value) {
        this.ifId = value;
    }

    /**
     * Gets the value of the ifName property.
     * 
     * @return
     *     possible object is
     *     {@link String }
     *     
     */
    public String getIfName() {
        return ifName;
    }

    /**
     * Sets the value of the ifName property.
     * 
     * @param value
     *     allowed object is
     *     {@link String }
     *     
     */
    public void setIfName(String value) {
        this.ifName = value;
    }

    @Override
    public long getSize(Object arg0, Class arg1, Type arg2, Annotation[] arg3,
            MediaType arg4) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public boolean isWriteable(Class arg0, Type arg1, Annotation[] arg2,
            MediaType arg3) {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public void writeTo(Object arg0, Class arg1, Type arg2, Annotation[] arg3,
            MediaType arg4, MultivaluedMap arg5, OutputStream arg6)
            throws IOException, WebApplicationException {
        // TODO Auto-generated method stub

    }

}

任何人都可以告诉我为什么会发生这种情况，因为我可以使用setter方法设置值。