如何通过注解实现接口返回数据脱敏？

左手的ㄟ右手 2024-03-26 14:48 75阅读 0赞

#### 思路 ####

1.要做成可配置多策略的脱敏操作，要不然一个个接口进行脱敏操作，重复的工作量太多，很显然违背了“多写一行算我输”的程序员规范，思来想去，定义数据脱敏注解和数据脱敏逻辑的接口， 在返回类上，对需要进行脱敏的属性加上，并指定对应的脱敏策略操作

2.接下来我只需要拦截控制器返回的数据，找到带有脱敏注解的属性操作即可，一开始打算用@ControllerAdvice去实现，但发现需要自己去反射类获取注解，当返回对象比较复杂，需要递归去反射，性能一下子就会降低，于是换种思路，我想到平时使用的@JsonFormat，跟我现在的场景很类似，通过自定义注解跟字段解析器，对字段进行自定义解析，

#### 代码 ####

1. 自定义数据注解，并可以配置数据脱敏策略

@Target({ElementType.FIELD, ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface DataMasking {
    
        DataMaskingFunc maskFunc() default DataMaskingFunc.NO_MASK;
    
    }

2. 自定义Serializer，参考jackson的StringSerializer，下面的示例只针对String类型进行脱敏

public interface DataMaskingOperation {
    
        String MASK_CHAR = "*";
        
        String mask(String content, String maskChar);
    
    }
    
    
    public enum DataMaskingFunc {
    
         /**
         *  脱敏转换器
         */
         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. 自定义AnnotationIntrospector，适配我们自定义注解返回相应的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. 覆盖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. 返回对象加上注解

public class User implements Serializable {
        /**
         * 主键ID
         */
        private Long id;
    
        /**
         * 姓名
         */
        @DataMasking(maskFunc = DataMaskingFunc.ALL_MASK)
        private String name;
    
        /**
         * 年龄
         */
        private Integer age;
    
        /**
         * 邮箱
         */
        @DataMasking(maskFunc = DataMaskingFunc.ALL_MASK)
        private String email;
    
    }