如何利用Jackson序列化忽略指定类型的属性详解

{
 "namespace": "cc.unmi.data",
 "type": "record",
 "name": "User",
 "fields": [
 {"name": "name", "type": "string"},
 {"name": "address", "type": ["string", "null"]}
 ]
}

ObjectMapper objectMapper = new ObjectMapper() ;
User user = User.newBuilder().setName("Yanbin").setAddress("Chicago").build();
System.out.println(objectMapper.writeValueAsString(user));

 public org.apache.avro.Schema getSchema() { return SCHEMA$; }

 public Schema getValueType() {
 throw new AvroRuntimeException("Not a map: "+this);
 }

@JsonIgnoreType
@interface IgnoreAvroSchemaField {
}

ObjectMapper objectMapper = new ObjectMapper() ;
objectMapper.addMixIn(Schema.class, IgnoreAvroSchemaField.class);
 
User user = User.newBuilder().setName("Yanbin").setAddress("Chicago").build();
System.out.println(objectMapper.writeValueAsString(user));

class AvroSchemaSerializer extends JsonSerializer<Schema> {
 
 @Override
 public void serialize(Schema value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
 jgen.writeString(value.getFullName()); //直接输出当前 Apache avro 对象的全限类名
 }
}

ObjectMapper objectMapper = new ObjectMapper() ;
SimpleModule simpleModule = new SimpleModule("SimpleModule", Version.unknownVersion());
simpleModule.addSerializer(Schema.class, new AvroSchemaSerializer());
objectMapper.registerModule(simpleModule);
 
User user = User.newBuilder().setName("Yanbin").setAddress("Chicago").build();
System.out.println(objectMapper.writeValueAsString(user));

 jgen.writeString(value.toString());

 System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(user));
{
 "name" : "Yanbin",
 "address" : "Chicago",
 "schema" : "{\"type\":\"record\",\"name\":\"User\",\"namespace\":\"cc.unmi.data\",\"fields\":[{\"name\":\"name\",\"type\":\"string\"},{\"name\":\"address\",\"type\":[\"string\",\"null\"]}]}"
}

@JsonFilter("filter out apache avro schema field") //字符串值要与下面 addFilter("xxx") 保持一致
class PropertyFilterMixIn {}

 ObjectMapper objectMapper = new ObjectMapper() ;
 objectMapper.addMixIn(SpecificRecordBase.class, PropertyFilterMixIn.class); //对 SpecificRecordBase 类型的对象应用
 FilterProvider filterProvider = new SimpleFilterProvider() //对 SpecificRecordBase 类型(如 User) 的名为 "schema" 属性屏蔽
  .addFilter("filter out apache avro schema field", SimpleBeanPropertyFilter.serializeAllExcept("schema"));
 objectMapper.setFilterProvider(filterProvider);
 
 User user = User.newBuilder().setName("Yanbin").setAddress("Chicago").build();
 System.out.println(objectMapper.writeValueAsString(user));