Question

我在尝试制作REST服务时遇到问题。我使用内置的GlassFish 4.1和Jersay 2.1。

@Path("/driver")
@RequestScoped
public class DriverResource {
    private static Logger logger = LogManager.getLogger(DriverResource.class);

        @Inject
        private DriverManager driverManager;

        private SharedResponseFactory responseFactory = new SharedResponseFactory();

        @GET
        @Path("/login/{pesel}/{password}")
        @Produces("application/json")
        public Response logIn(@PathParam("pesel") String pesel, @PathParam("password") String password) {
            try {
                Driver driver = driverManager.logIn(pesel, password);

                logger.debug("Zalogowano kierowcę: " + driver.getFullName());
                return responseFactory.getSuccesResponse(driver);
            } catch (ErrorDAOException e) {
                logger.catching(e);
                return responseFactory.getFailureResponse(e);
            } catch (NoDataFoundDAOException e) {
                logger.catching(e);
                return responseFactory.getFailureResponse(e);
            } catch (Exception e) {
                logger.catching(e);
                return responseFactory.getFailureResponse(e);
            }
        }
    }

当我试图返回我的实体时，我会得到这样的回复：

{}

在我的实体中有许多循环引用，我不会在实际实现上操作但是接口。我需要按照我的Android应用程序中的Retrofit进行反序列化的方式。

Glassfish的日志是空的，没有与休息有关的错误。我不知道如何让它发挥作用。

我尝试使用@JsonIdentityInfo来处理循环引用和@JsonTypeInfo以使接口可以反序列化。

我认为有一个小技巧会让它发挥作用，但不幸的是我不知道......

Answer 1

我找到了一种测试循环引用的相对简单的方法。如果您使用JAXB（包含在glassfish中），您可以尝试将实体编组为XML。如果找到任何循环引用，则抛出JAXBException。

这是一种将对象编组为XML的方法：

public static <T> String marshalToXml(T instance) throws javax.xml.bind.JAXBException {
    JAXBContext jaxbContext = JAXBContext.newInstance(instance.getClass());
    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
    jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    StringWriter writer = new StringWriter();
    jaxbMarshaller.marshal(instance, writer);
    return writer.toString();
}

并且服务可以像这样测试对象：

@Path("/driver")
@RequestScoped
public class DriverResource {

    private static Logger logger = LogManager.getLogger(DriverResource.class);

    @Inject
    private DriverManager driverManager;

    private SharedResponseFactory responseFactory = new SharedResponseFactory();

    @GET
    @Path("/login/{pesel}/{password}")
    @Produces("application/json")
    public Response logIn(@PathParam("pesel") String pesel, @PathParam("password") String password) {
        try {
            Driver driver = driverManager.logIn(pesel, password);

            marshalToXml(driver); //remember to import static method

            logger.debug("Zalogowano kierowcę: " + driver.getFullName());
            return responseFactory.getSuccesResponse(driver);
        } catch (ErrorDAOException e) {
            logger.catching(e);
            return responseFactory.getFailureResponse(e);
        } catch (NoDataFoundDAOException e) {
            logger.catching(e);
            return responseFactory.getFailureResponse(e);
        } catch (JAXBException e) {
            //view error message to see cyclic reference
            logger.catching(e);
            return responseFactory.getFailureResponse(e);
        } catch (Exception e) {
            logger.catching(e);
            return responseFactory.getFailureResponse(e);
        }
    }
}

RESTful服务空响应

1 个答案: