It's too strong. An annotation handles the data desensitization returned by the interface

• Ideas

• Code

  • 1. Custom data annotation , Data desensitization strategy can be configured

  • 2. Customize Serializer, Reference resources jackson Of StringSerializer, The following example is only for String Type for desensitization

  • 3. Customize AnnotationIntrospector, Adapt our custom annotation to return the corresponding Serializer

  • 4. Cover ObjectMapper

  • 5. Return the object and annotate it

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A pleasant afternoon , Suddenly miss product came up to me , Interrupt my short fishing time, Try to have in-depth communication with me , It's good that I was on guard , Open Rui star Order page of , Hint that there is no one coffee Unsolvable needs , Requirements are information returned by some interfaces , Sensitive data must be desensitized , I thought the other way , Indicate a problem , Make arrangements now .

Ideas

1. It is necessary to make desensitization operation with configurable multiple strategies , Otherwise, desensitize the interfaces one by one , Too much repetitive work , It's obviously against “ I'll lose if I write one more line ” Programmer specification for , reasoning , Define the interface between data desensitization annotation and data desensitization logic , On the return class , Add... To the attributes that need desensitization , And specify the corresponding desensitization policy operation .

2. Next, I just need to intercept the data returned by the controller , Find the attribute operation with desensitization annotation , At first, I planned to use @ControllerAdvice To achieve , However, it is found that you need to reflect the class to get annotations , When the return object is complex , Recursive de reflection is required , Performance will degrade all at once , So change your mind , I think of the usual @JsonFormat, It is very similar to my current scene , Through custom annotation and field parser , Custom parsing of fields ,tql

Code

1. Custom data annotation , Data desensitization strategy can be configured

@Target({ElementType.FIELD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DataMasking {

    DataMaskingFunc maskFunc() default DataMaskingFunc.NO_MASK;

}

2. Customize Serializer, Reference resources jackson Of StringSerializer, The following example is only for String Type for desensitization

public interface DataMaskingOperation {

    String MASK_CHAR = "*";
    
    String mask(String content, String maskChar);

}

public enum DataMaskingFunc {

     /**
     *   Desensitization converter 
     */
     NO_MASK((str, maskChar) -> {
        return str;
     }),
     ALL_MASK((str, maskChar) -> {
        if (StringUtils.hasLength(str)) {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < str.length(); i++) {
                sb.append(StringUtils.hasLength(maskChar) ? maskChar : DataMaskingOperation.MASK_CHAR);
            }
            return sb.toString();
        } else {
            return str;
        }
    });

    private final DataMaskingOperation operation;

    private DataMaskingFunc(DataMaskingOperation operation) {
        this.operation = operation;
    }

    public DataMaskingOperation operation() {
        return this.operation;
    }

}

public final class DataMaskingSerializer extends StdScalarSerializer<Object> {
    private final DataMaskingOperation operation;

    public DataMaskingSerializer() {
        super(String.class, false);
        this.operation = null;
    }

    public DataMaskingSerializer(DataMaskingOperation operation) {
        super(String.class, false);
        this.operation = operation;
    }


    public boolean isEmpty(SerializerProvider prov, Object value) {
        String str = (String)value;
        return str.isEmpty();
    }

    public void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException {
        if (Objects.isNull(operation)) {
            String content = DataMaskingFunc.ALL_MASK.operation().mask((String) value, null);
            gen.writeString(content);
        } else {
            String content = operation.mask((String) value, null);
            gen.writeString(content);
        }
    }

    public final void serializeWithType(Object value, JsonGenerator gen, SerializerProvider provider, TypeSerializer typeSer) throws IOException {
        this.serialize(value, gen, provider);
    }

    public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
        return this.createSchemaNode("string", true);
    }

    public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException {
        this.visitStringFormat(visitor, typeHint);
    }
}

3. Customize AnnotationIntrospector, Adapt our custom annotation to return the corresponding Serializer

@Slf4j
public class DataMaskingAnnotationIntrospector extends NopAnnotationIntrospector {

    @Override
    public Object findSerializer(Annotated am) {
        DataMasking annotation = am.getAnnotation(DataMasking.class);
        if (annotation != null) {
            return new DataMaskingSerializer(annotation.maskFunc().operation());
        }
        return null;
    }

}

4. Cover ObjectMapper

@Configuration(
        proxyBeanMethods = false
)
public class DataMaskConfiguration {

    @Configuration(
            proxyBeanMethods = false
    )
    @ConditionalOnClass({Jackson2ObjectMapperBuilder.class})
    static class JacksonObjectMapperConfiguration {
        JacksonObjectMapperConfiguration() {
        }

        @Bean
        @Primary
        ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
            ObjectMapper objectMapper = builder.createXmlMapper(false).build();
            AnnotationIntrospector ai = objectMapper.getSerializationConfig().getAnnotationIntrospector();
            AnnotationIntrospector newAi = AnnotationIntrospectorPair.pair(ai, new DataMaskingAnnotationIntrospector());
            objectMapper.setAnnotationIntrospector(newAi);
            return objectMapper;
        }
    }

}

5. Return the object and annotate it

public class User implements Serializable {
    /**
     *  Primary key ID
     */
    private Long id;

    /**
     *  full name 
     */
    @DataMasking(maskFunc = DataMaskingFunc.ALL_MASK)
    private String name;

    /**
     *  Age 
     */
    private Integer age;

    /**
     *  mailbox 
     */
    @DataMasking(maskFunc = DataMaskingFunc.ALL_MASK)
    private String email;

}

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