java - 自定义即时解串器无法正常工作。不断收到 HttpMessageNotReadableException

Question

我正在尝试使用 postman 并将这些值放入数据库中，但我不断收到异常。

我试图从 postman 反序列化什么:

{
    "end_date": "2443-11-34 12:43:23",
    "start_date":  "2443-11-34 12:43:23"
}

我得到的异常:

2020-05-20 10:55:04.572  WARN 4452 --- [nio-8080-exec-2] .w.s.m.s.DefaultHandlerExceptionResolver :
 Resolved [org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot 
deserialize value of type `java.time.Instant` from String "2443-11-34 12:43:23": Failed to deserialize 
java.time.Instant: (java.time.format.DateTimeParseException) Text '2443-11-34 12:43:23' could not be 
parsed at index 10; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot 
deserialize value of type `java.time.Instant` from String "2443-11-34 12:43:23": Failed to deserialize 
java.time.Instant: (java.time.format.DateTimeParseException) Text '2443-11-34 12:43:23' could not be parsed at index 10
 at [Source: (PushbackInputStream); line: 3, column: 17] (through reference chain: 
com.project.rushhour.model.post.AppointmentPostDTO["end_date"])]

预约实体:

@Entity
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Appointment extends BaseEntity {

   @NotNull
   @DateTimeFormat(style = "yyyy-MM-dd HH:mm:ss")
   @JsonFormat(shape=JsonFormat.Shape.STRING, pattern="yyyy-MM-dd HH:mm:ss")
   @JsonDeserialize(using = JacksonInstantDeserializer.class)
   private Instant startDate;

   @NotNull
   @JsonDeserialize(using = JacksonInstantDeserializer.class)
   @DateTimeFormat(style = "yyyy-MM-dd HH:mm:ss")
   @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
   private Instant endDate;

我的类(class)预约:

@Data
@NoArgsConstructor
@AllArgsConstructor
public abstract class AppointmentDTO extends BaseDTO {

    @JsonProperty("start_date")
    private Instant startDate;

    @JsonProperty("end_date")
    private Instant endDate;

我使用的 AppointmentGetDTO 类

public class AppointmentGetDTO extends AppointmentDTO {
}

我还拥有所有 Jackson 依赖项

我使用的自定义反序列化器:

public class JacksonInstantDeserializer extends StdDeserializer<Instant> {
    public JacksonInstantDeserializer() { this(null); }
    public JacksonInstantDeserializer(Class<?> clazz) { super(clazz); }

    @Override
    public Instant deserialize(JsonParser parser, DeserializationContext ctx) throws IOException {
        return Instant.parse(parser.getText());
    }
}

Answer 1

您应该为您的类 AppointmentGetDTO 而不是 Instant 类创建一个 CustomDeserializer。

我们需要使用Deserializer注册AppointmentDTO类。下面我提供了相关的代码更改。用户调试器并在解串器中创建断点来测试转换逻辑。

如需进一步阅读，请结账:jackson-deserialization还有这个 Stackoverflow answer

阅读本文以了解替代方法:JsonComponent

预约DTO:

@Data
@NoArgsConstructor
@AllArgsConstructor
public abstract class AppointmentDTO {

    @JsonProperty("start_date")
    private Instant startDate;

    @JsonProperty("end_date")
    private Instant endDate;
}

预约GetDTO:

@JsonDeserialize(using= JacksonInstantDeserializer.class)
public class AppointmentGetDTO extends AppointmentDTO {
    public AppointmentGetDTO(Instant s, Instant e) {
        super(s,e);
    }
}

用于 AppointmentGetDTO 的自定义反序列化器

public class JacksonInstantDeserializer extends StdDeserializer<AppointmentGetDTO> {
    public JacksonInstantDeserializer() { this(AppointmentDTO.class); }
    public JacksonInstantDeserializer(Class<?> clazz) { super(clazz); }

    @Override
    public AppointmentGetDTO deserialize(JsonParser parser, DeserializationContext ctx) throws IOException {
        JsonNode node = parser.getCodec().readTree(parser);
        Instant s=null;
        Instant e=null;
        if(node.get("start_date") != null) {
            s=Instant.parse(node.get("start_date").asText());
        }
        if(node.get("end_date")!=null) {
            e=Instant.parse(node.get("end_date").asText());
        }
        return new AppointmentGetDTO(s,e);
    }
}

然后你可以创建com.fasterxml.jackson.databind.Module的bean，如下所示:

    @Bean
    public Module dynamoDemoEntityDeserializer() {
        SimpleModule module = new SimpleModule();
        module.addDeserializer(AppointmentGetDTO.class, new JacksonInstantDeserializer());
        return module;
    }

请求的 Controller 映射:

@PostMapping
public AppointmentDTO convert(@RequestBody  AppointmentGetDTO appointmentDTO) {
    System.out.println(appointmentDTO.getStartDate());
    System.out.println(appointmentDTO.getEndDate());
    return appointmentDTO;
}

请求 json:

{
    "end_date": "2443-11-12T12:43:23Z",
    "start_date":  "2443-11-12T12:43:23Z"
}