SpringBoot自定义注解+Jackson序列化器实现数据脱敏

{
    "username": "测试用户",
    "phone":    "13812346789",    ❌明文暴露
    "email":    "test@qq.com"     ❌
}

{
    "username": "测试用户",
    "phone":    "138****6789",    ✅
    "email":    "t***@qq.com"     ✅
}    

public enum SensitiveType{
    MOBILe,    //手机号
    EMAIL,     //邮箱
    ID_CARD    //身份证
}

public class SensitiveUtils {

    /** 手机号：13812346789 -> 138****6789（保留前3后4） */
    public static String maskMobile(String mobile) {
        if (mobile == null || mobile.length() != 11) {
            return mobile;   // 格式不符时原样返回，不抛异常
        }
        return mobile.substring(0, 3) + "****" + mobile.substring(7);
    }

    /** 邮箱：test@qq.com -> t****@qq.com（保留首字母 + @后面） */
    public static String maskEmail(String email) {
        if (email == null || !email.contains("@")) {
            return email;
        }
        int atIndex = email.indexOf("@");
        return email.substring(0, 1) + "****" + email.substring(atIndex);
    }

    /** 身份证：110101199001011234 -> 110***********1234（保留前3后4） */
    public static String maskIdCard(String idCard) {
        if (idCard == null || idCard.length() != 18) {
            return idCard;
        }
        return idCard.substring(0, 3) + "***********" + idCard.substring(14);
    }
}

public class SensitiveJsonSerializer extends JsonSerializer<String>
        implements ContextualSerializer {

    /** 当前字段的脱敏类型 */
    private SensitiveType type;

    /** 无参构造：Jackson 反射创建实例时调用 */
    public SensitiveJsonSerializer() {
    }

    /** 有参构造：内部使用，携带脱敏类型 */
    private SensitiveJsonSerializer(SensitiveType type) {
        this.type = type;
    }

    /** 核心方法：序列化时打码 */
    @Override
    public void serialize(String value, JsonGenerator gen, SerializerProvider serializers)
            throws IOException {
        if (value == null) {
            gen.writeNull();
            return;
        }
        gen.writeString(mask(value, type));
    }

    /** 关键方法：读取字段上的 @Sensitive 注解，拿到脱敏类型 */
    @Override
    public JsonSerializer<?> createContextual(SerializerProvider prov, BeanProperty property) {
        if (property != null) {
            Sensitive annotation = property.getAnnotation(Sensitive.class);
            if (annotation != null) {
                return new SensitiveJsonSerializer(annotation.type());
            }
        }
        return this;
    }

    /** 根据类型调用对应的打码方法 */
    private String mask(String value, SensitiveType type) {
        switch (type) {
            case MOBILE: return SensitiveUtils.maskMobile(value);
            case EMAIL: return SensitiveUtils.maskEmail(value);
            case ID_CARD: return SensitiveUtils.maskIdCard(value);
            default: return value;
        }
    }
}

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@JacksonAnnotationsInside                       // 关键：允许组合 @JsonSerialize
@JsonSerialize(using = SensitiveJsonSerializer.class)
public @interface Sensitive {

    /** 脱敏类型，默认手机号 */
    SensitiveType type() default SensitiveType.MOBILE;
}

public class UserProfileVO{

    @Sensitive(type = SensitiveType.MOBILE)
    private String phone;

    @Sensitive(type = SensitiveType.EMAIL)
    private String email;

    //其他字段...
}