java - 如何将 fasterxml.jackson.ObjectMapper @Inject 到 JAX-RS 资源中？

Question

我正在尝试将 ObjectMapper 类的一个实例注入(inject)到我的 JAX-RS 资源中，但我看到了这个错误，

[ERROR   ] Api type [com.fasterxml.jackson.databind.ObjectMapper] is not found with the qualifiers 
Qualifiers: [@javax.enterprise.inject.Default()]
for injection into Field Injection Point, field name :  mapper, Bean Owner : [PageMetaResource, Name:null, WebBeans Type:MANAGED, API Types:[com.lmig.pi.ado.meta.resources.PageMetaResource], Qualifiers:[javax.enterprise.inject.Any,javax.enterprise.inject.Default]]

我在 WEB-INF 目录中有一个空的 beans.xml 文件，

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>

我想知道是不是我的 Application.getSingletons() 方法导致了这个问题，

@Override
public Set<Object> getSingletons()
{
    Set<Object> set = new HashSet<>();

    DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

    ObjectMapper mapper = new ObjectMapper();

    mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
    mapper.setSerializationInclusion(JsonInclude.Include.NON_DEFAULT);
    mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
    mapper.configure(SerializationFeature.WRITE_EMPTY_JSON_ARRAYS, false);
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    mapper.setDateFormat(df);

    JacksonJsonProvider provider = new JacksonJsonProvider();
    provider.setMapper(mapper);

    set.add(provider);

    return set;
}

我的资源类是这样的，

public class PageMetaResource extends BasePresentationResource
{
    /**
     * The logger of the class
     */
    private static final Logger logger = Logger.getLogger(PageMetaResource.class);

    /**
     * Factory that produces a {@link PageMetaServices} instance for this resource.
     */
    private ServiceFactory serviceFactory;

    /**
     * Factory that produces a {@link PageMetaResourceBean} instance for this resource.
     */
    private ResourceBeanFactory resourceBeanFactory;

    /**
     * The servlet context.
     */
    @Context
    private ServletContext context;

    @Inject
    private ObjectMapper mapper;

    /**
     * Constructor
     */
    @Inject
    public PageMetaResource(ServiceFactory serviceFactory, ResourceBeanFactory resourceBeanFactory)
    {
        this.serviceFactory = serviceFactory;        
        this.resourceBeanFactory = resourceBeanFactory;
    }
...
}

有什么想法吗？我尝试将 @inject 注入(inject)到构造函数中 - 但抛出了类似的错误。

感谢您的帮助，

安德鲁

PS:我正在部署到 Websphere Application Server v8.5 Liberty Profile

Answer 1

您的 CDI 容器未找到 ObjectMapper 的生产者。看看here .