Question

我想过滤掉响应中的某些字段。应当在将Java对象序列化为JSON之前进行过滤。考虑：

public class Entity {

    @JsonProperty("some_property")
    String someProperty;

    @JsonProperty("nested_entity")
    @OneToMany(mappedBy = "entity", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    NestedEntity nestedEntity;

    // other fields for eg fieldA, fieldB
}

API端点

get api/entity/{id}?fields=some_property,field_a

现在要问的是，在o / p中，我们应该只过滤出someProperty和fieldA。喜欢

{
    "some_property": "foo",
    "field_a": "bar"
}

但是由于这些是JSON字段而不是Java对象字段，所以我无法通过反射过滤或获取这些字段。有没有一种方法可以实现这一点，即基于json字段过滤Java对象？

仅供参考：序列化之前进行过滤的优势在于，除非需要这些字段，否则将保存惰性字段的DB调用

谢谢！

Answer 1

根据使用@JsonFilter的@robocode的建议，并且还支持空fields或不添加任何过滤杰克逊配置的字段

@JsonFilter("entityFilter")
public class Entity {

    @JsonProperty("some_property")
    String someProperty;
    // other fields for eg fieldA, fieldB
}

@Configuration
public class JacksonConfiguration { 
    public JacksonConfiguration(ObjectMapper objectMapper) {
        objectMapper.setFilterProvider(new SimpleFilterProvider().setFailOnUnknownId(false));
    } 
}

public class FieldMapper {
    
    @SneakyThrows
    public static Dto getFilteredFields(Dto make, String fields[]) {
        ObjectMapper objectMapper = new ObjectMapper();
        if(ArrayUtils.isNotEmpty(fields)) {
            FilterProvider filters = new SimpleFilterProvider().addFilter(
                    "entityFilter", SimpleBeanPropertyFilter.filterOutAllExcept(fields)
            );
            objectMapper.setFilterProvider(filters);
        } else {
            objectMapper.setFilterProvider(new SimpleFilterProvider().setFailOnUnknownId(false));
        }
        JsonNode j = objectMapper.readTree(objectMapper.writeValueAsString(make));
        return objectMapper.convertValue(j, Dto.class);
    }
}

// controller code to get the dto for api/entity/{id}?fields=some_property,field_a
Dto filteredFields = getFilteredFields(dto, fields);
return filteredFields

如何从JSON字段名称获取Java对象字段的名称

1 个答案: