JSON解析错误：由于输入结束而没有要映射的内容

Question

POST方法出错。使用GET和DELETE方法工作。

  

org.springframework.http.converter.HttpMessageNotReadableException：JSON解析错误：由于输入结束而没有要映射的内容;嵌套异常是com.fasterxml.jackson.databind.exc.MismatchedInputException：由于输入结束而没有要映射的内容

public class ParameterDeserializer<T> extends JsonDeserializer<Parameter<T>> {

@Override
public Parameter<T> deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
    ObjectMapper objectMapper = (ObjectMapper) jsonParser.getCodec();
    ObjectNode jsonNodes = objectMapper.readTree(jsonParser);
    Class<? extends Parameter> parameterClass = null;
    Map parameterObjectMap = objectMapper.convertValue(jsonNodes, Map.class);
    Object value = parameterObjectMap.get("value");
    if (value instanceof String) {
        parameterClass = StringValue.class;
    } else if (value instanceof Long || value instanceof Integer) {
        parameterClass = LongValue.class;
    } else if (value instanceof Boolean) {
        parameterClass = BoolValue.class;
    } else if (value == null) {
        return null;
    }
    return objectMapper.readValue(jsonParser, parameterClass);
}
}


@Data
@Entity
@Table(name = "parameter")
@Inheritance(strategy = InheritanceType.JOINED)
@JsonDeserialize(using = ParameterDeserializer.class)
@DiscriminatorColumn(name = "parameter", discriminatorType = DiscriminatorType.STRING)
public abstract class Parameter<T> {

[...]

private T value;

public abstract T getValue();

public abstract void setValue(T value);
}

@Entity
@DiscriminatorValue(value = "string")
public class StringValue extends Parameter<String> {

@Column(name = "string_value")
private String stringValue;

@Override
public String getValue() {
    return stringValue;
}

@Override
public void setValue(String stringValue) {
    this.stringValue = stringValue;
}
}