java - 自定义类上的 readEntity 抛出 MessageBodyProviderNotFoundException

Question

我正在用 Java 为一个类开发 RESTful API。我正在使用 JAX-RS 我遵循了本教程 "JAX-RS Jersey" 。一切正常，除了当我尝试执行 response.readEntity(MyTable.class) 来创建我的 MyTable 类的新 Object 时，一切都按预期进行。已经创造出来了。这对于 String.class 来说效果很好，它将所有 JSON 信息作为字符串读取，但它无法将其解析为新的 Object我的定制类(class)。我已经阅读了很多这方面的内容，并且已经设置了属性的所有 setter 和 getter 以及一个空的构造函数，但它无法将信息解析为我的自定义类的新对象。我收到 MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=class com.beans.MyTable, genericType=class com.beans.MyTable. 错误。

MyTable.java

 private Integer id;
    private String name;

    public MyTable() {

    }

    public MyTable(Integer id, String name) {
        this.id = id;
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "MyTable [id=" + id + ", name=" + name + "]";
    }

MyClient.java

Client client = ClientBuilder.newClient( new ClientConfig().register( LoggingFeature.class ) );
WebTarget webTarget = client.target("http://localhost:8080/App/rest").path("test");

Invocation.Builder invocationBuilder =  webTarget.request(MediaType.APPLICATION_JSON);
Response response = invocationBuilder.get();

//Does not work and gives error
MyTable table = response.readEntity(MyTable.class);
System.out.println(table.toString());

MyService.java

@PermitAll
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response test() {
        MyTable table = new MyTable();
        table.setId(1);
        table.setName("mesa de teste");

        GenericEntity<MyTable> genericEntity = new GenericEntity<MyTable>(table, MyTable.class);
        return Response.ok().entity(genericEntity).build();
    }

错误

Exception in thread "main" org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=application/json, type=class com.beans.MyTable, genericType=class com.beans.MyTable.
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:231)
    at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:155)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1085)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:874)
    at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:808)
    at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:326)
    at org.glassfish.jersey.client.InboundJaxrsResponse$1.call(InboundJaxrsResponse.java:115)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:419)
    at org.glassfish.jersey.client.InboundJaxrsResponse.runInScopeIfPossible(InboundJaxrsResponse.java:267)
    at org.glassfish.jersey.client.InboundJaxrsResponse.readEntity(InboundJaxrsResponse.java:112)
    at com.client.MyClient.main(MyClient.java:31)

Answer 1

根据链接的指南，作者使用 Gson 创建了一个客户 JSON 提供程序。您需要向客户端注册此提供程序，就像您在服务器端所做的那样。

new ClientConfig()
    .register( LoggingFeature.class )
    .register( GsonMessageBodyHandler.class )

阅读chapter 8 and 9 of the Jersey docs了解有关提供程序以及如何使用它们在 Jersey 中进行序列化和反序列化的更多信息。