一个注解搞定接口数据脱敏，太强了！

Posted 2022-09-01 Java技术栈

来源：juejin.cn/post/7110110794188062727

下午惬意时光，突然产品小姐姐走到我面前，打断我短暂的摸鱼time，企图与我进行深入交流，还好我早有防备没有闪，打开瑞star的点单页面，暗示没有一杯coffee解决不了的需求，需求是某些接口返回的信息，涉及到敏感数据的必须进行脱敏操作，我思考一反，表示某问题，马上安排。

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，tql

代码

Spring Boot 基础就不介绍了，推荐下这个实战教程：

https://github.com/javastacks/spring-boot-best-practice

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;

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