我有一个具有多个@ManyToOne关联的实体。我正在使用spring-boot应用程序公开REST API。目前,我有多个REST API,它们返回包括关联在内的整个实体的json响应。
但是我不想序列化所有REST API中的所有关联对象。例如
API-1应该返回父对象+ associationA对象 API-2应该返回父对象+ associationA + associationB对象 API-3应该返回parent + associationB + associationc + associationD
因此,在我的序列化过程中,我想忽略除API-1的associationA以外的所有关联。 对于API-2,我想忽略A和B以外的其他关联
如何在Jackson序列化过程中动态忽略这些属性。
注意: 我在同一个班上,我不想为每个API创建任何dto
任何建议都会受到赞赏。
答案 0 :(得分:7)
我汇总了三种在Jackson中执行动态过滤的方法。其中之一必须满足您的需求。
@JsonView
您可以使用@JsonView
:
public class Views {
interface Simple { }
interface Detailed extends Simple { }
}
public class Foo {
@JsonView(Views.Simple.class)
private String name;
@JsonView(Views.Detailed.class)
private String details;
// Getters and setters
}
@RequestMapping("/foo")
@JsonView(Views.Detailed.class)
public Foo getFoo() {
Foo foo = new Foo();
return foo;
}
或者,您可以使用MappingJacksonValue
动态设置视图。
@RequestMapping("/foo")
public MappingJacksonValue getFoo() {
Foo foo = new Foo();
MappingJacksonValue result = new MappingJacksonValue(foo);
result.setSerializationView(Views.Detailed.class);
return result;
}
BeanSerializerModifier
您可以扩展BeanSerializerModifier
,然后覆盖changeProperties()
方法。它允许您根据需要添加,删除或替换任何要序列化的属性:
public class CustomSerializerModifier extends BeanSerializerModifier {
@Override
public List<BeanPropertyWriter> changeProperties(SerializationConfig config,
BeanDescription beanDesc, List<BeanPropertyWriter> beanProperties) {
// In this method you can add, remove or replace any of passed properties
return beanProperties;
}
}
然后将序列化程序注册为ObjectMapper
中的模块:
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new SimpleModule() {
@Override
public void setupModule(SetupContext context) {
super.setupModule(context);
context.addBeanSerializerModifier(new CustomSerializerModifier());
}
});
@JsonFilter
与SimpleBeanPropertyFilter
一起使用另一种方法涉及@JsonFilter
:
@JsonFilter("customPropertyFilter")
public class Foo {
private String name;
private String details;
// Getters and setters
}
根据您的需要扩展SimpleBeanPropertyFilter
并覆盖serializeAsField()
方法:
public class CustomPropertyFilter extends SimpleBeanPropertyFilter {
@Override
public void serializeAsField(Object pojo, JsonGenerator jgen,
SerializerProvider provider,
PropertyWriter writer) throws Exception {
// Serialize a field
// writer.serializeAsField(pojo, jgen, provider, writer);
// Omit a field from serialization
// writer.serializeAsOmittedField(pojo, jgen, provider);
}
}
然后在您的ObjectMapper
中注册过滤器:
FilterProvider filterProvider = new SimpleFilterProvider()
.addFilter("customPropertyFilter", new CustomPropertyFilter());
ObjectMapper mapper = new ObjectMapper();
mapper.setFilterProvider(filterProvider);
如果要将过滤器设置为“全局” ,即要应用于所有bean,则可以创建一个混合类并用@JsonFilter("customPropertyFilter")
进行注释:< / p>
@JsonFilter("customPropertyFilter")
public class CustomPropertyFilterMixIn {
}
然后将混合类绑定到Object
:
mapper.addMixIn(Object.class, CustomPropertyFilterMixIn.class);
答案 1 :(得分:0)
我已经对从 db 获取的数据实施动态过滤器并使用 rest api 返回它。我避免使用 MappingJacksonValue。因为它在对象链接时出现问题
@GetMapping("/courses")
public ResponseEntity<JpaResponse> allCourse() throws Exception {
JpaResponse response = null;
ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
List<Course> course = service.findAllCourse();
SimpleBeanPropertyFilter filter = SimpleBeanPropertyFilter.filterOutAllExcept("name","reviews");
FilterProvider filterProvider = new SimpleFilterProvider().addFilter("jpafilter", filter).setFailOnUnknownId(false);
ObjectWriter writer = mapper.writer(filterProvider);
String writeValueAsString = writer.writeValueAsString(course);
List<Course> resultcourse = mapper.readValue(writeValueAsString,List.class);
response = new JpaResponse(HttpStatus.OK.name(),resultcourse);
return new ResponseEntity<>(response, HttpStatus.OK);
}
public class JpaResponse {
private String status;
private Object data;
public JpaResponse() {
super();
}
public JpaResponse(String status, Object data) {
super();
this.status = status;
this.data = data;
}
}