前言

根据公司业务需要，灵活对客户敏感信息进行加解密，这里采用mybatis拦截器进行简单实现个demo。

拦截器的使用

// 执行
Executor (update, query, flushStatements, commit, rollback, getTransaction, close, isClosed)
// 请求参数处理
ParameterHandler (getParameterObject, setParameters)
// 返回结果集处理
ResultSetHandler (handleResultSets, handleOutputParameters)
// SQL语句构建
StatementHandler (prepare, parameterize, batch, update, query)

我们要实现数据加密，进入数据库的字段不能是真实的数据，但是返回来的数据要真实可用，所以我们需要针对 Parameter 和 ResultSet 两种类型处理，同时为了更灵活的使用，我们需要自定义注解。

/**
 *需要加解密的字段注解
**/
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Encryption {
    String encryptionType() default "";
}

编写一下加解密算法（随便找的）

**
 * @desc: AES对称加密，对明文进行加密、解密处理
 * @author:
 * @createTime: 20231014 上午9:54:52
 * @version: v0.0.1
 */
public class AESUtil {
    private static final String KEY_ALGORITHM = "AES";
    private static final String CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";


    /**
     * @desc: AES对称-加密操作
     * @version: v0.0.1
     * @param keyStr 进行了Base64编码的秘钥
     * @param data 需要进行加密的原文
     * @return String 数据密文，加密后的数据，进行了Base64的编码
     */
    public static String encrypt(String keyStr, String data) throws Exception {
        // 转换密钥
        Key key = new SecretKeySpec(Base64.getDecoder().decode(keyStr), KEY_ALGORITHM);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        // 加密
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] result = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(result);
    }
    /**
     * @desc: AES对称-解密操作
     * @version: v0.0.1
     * @param keyStr 进行了Base64编码的秘钥
     * @param data 需要解密的数据<span style="color:red;">（数据必须是通过AES进行加密后，对加密数据Base64编码的数据）</span>
     * @return String 返回解密后的原文
     */
    public static String decrypt(String keyStr, String data) throws Exception {
        // 转换密钥
        Key key = new SecretKeySpec(Base64.getDecoder().decode(keyStr), KEY_ALGORITHM);
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        // 解密
        cipher.init(Cipher.DECRYPT_MODE, key);
        byte[] result = cipher.doFinal(Base64.getDecoder().decode(data));
        return new String(result);
    }


    /**
     * @desc: 生成AES的秘钥，秘钥进行了Base64编码的字符串
     * @version: v0.0.1
     * @return String 对生成的秘钥进行了Base64编码的字符串
     */
    public static String keyGenerate() throws Exception {
        // 生成密钥
        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_ALGORITHM);
        keyGenerator.init(new SecureRandom());
        SecretKey secretKey = keyGenerator.generateKey();
        byte[] keyBytes = secretKey.getEncoded();
        return Base64.getEncoder().encodeToString(keyBytes);
    }
    public static void main(String[] args) throws Exception {
        System.out.println(
                keyGenerate()
        );

    }
}

编写一下加解密接口

/**
 * 加解密处理接口
 */
public interface CipherHandler {

    /**
     * 加密
     * @param data 需要加密的数据
     * @return 加密结果
     */
   String encrypt(String data) throws Exception;

    /**
     * 解密
     * @param data 需要加密的数据
     * @return 解密结果
     */
    String decrypt(String data) throws Exception;

}

public class AEScipher implements CipherHandler{
    private final static String keyStr="glRwFSBcKzppYVQiwT8M/Q==";

    @Override
    public String encrypt(String data) throws Exception {
        return AESUtil.encrypt(this.keyStr,data);
    }

    @Override
    public String decrypt(String data) throws Exception {
        return AESUtil.decrypt(this.keyStr,data);
    }

    public static CipherHandler getAEScipher(){
        return new AEScipher();
    }
}

接下来写一下加解密的拦截器

@Intercepts({
        @Signature(type = ParameterHandler.class, method = "setParameters", args = PreparedStatement.class),
})
@Component
@Slf4j
public class ParameterInterceptor implements Interceptor {

    private CipherHandler cipherHandler = AEScipher.getAEScipher();
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        DefaultParameterHandler parameterHandler = (DefaultParameterHandler) invocation.getTarget();
        // 获取参数对像，即 mapper 中 paramsType 的实例
        Field parameterField = parameterHandler.getClass().getDeclaredField("parameterObject");
        parameterField.setAccessible(true);
        // 取出实例
        Object parameterObject = parameterField.get(parameterHandler);
        try {
            // 搜索该方法中是否有需要加密的字段
            List<Field> fieldList = searchParamAnnotation(parameterHandler);
            //加密
            if(!CommonHelper.isEmpty(fieldList)){
                dealParamEncrypt(fieldList,parameterObject);
            }
            parameterField.set(parameterHandler, parameterObject);
            PreparedStatement ps = (PreparedStatement) invocation.getArgs()[0];
            parameterHandler.setParameters(ps);

        } catch (Exception e) {
            log.info(e.getMessage());
        }
        return invocation.proceed();
    }


    /**
     * 查找需要需要加密字段
     * @param parameterHandler
     * @return
     * @throws Exception
     */
    private List<Field> searchParamAnnotation(ParameterHandler parameterHandler) throws Exception {
        Class<DefaultParameterHandler> handlerClass = DefaultParameterHandler.class;
        Field mappedStatementFiled = handlerClass.getDeclaredField("mappedStatement");
        mappedStatementFiled.setAccessible(true);
        MappedStatement mappedStatement = (MappedStatement) mappedStatementFiled.get(parameterHandler);
        String methodName = mappedStatement.getId();
        // 获取Mapper类对象
        Class<?> mapperClass = Class.forName(methodName.substring(0, methodName.lastIndexOf('.')));
        methodName = methodName.substring(methodName.lastIndexOf('.') + 1);
        Method[] methods = mapperClass.getDeclaredMethods();
        Method method = null;
        for (Method m : methods) {
            if (m.getName().equals(methodName)) {
                method = m;
                break;
            }
        }
        List<Field> fieldList = new ArrayList<>();
        if (method != null) {
            Annotation[][] pa = method.getParameterAnnotations();
            Parameter[] parameters = method.getParameters();
            for (int i = 0; i < pa.length; i++) {
                Parameter parameter = parameters[i];
                String typeName = parameter.getParameterizedType().getTypeName();
                // 去除泛型导致的ClassNotFoundException
                Class<?> parameterClass = Class.forName(typeName.contains("<") ? typeName.substring(0, typeName.indexOf("<")) : typeName);
                Field[] declaredFields = parameterClass.getDeclaredFields();
                for (Field declaredField : declaredFields) {
                    Annotation annotation = declaredField.getAnnotation(Encryption.class);
                    if(!CommonHelper.isEmpty(annotation))fieldList.add(declaredField);
                }
            }
        }
        return fieldList;
    }

    /**
     * 处理加密类
     * @param fields
     * @param parameterObject
     * @throws Exception
     */
    private void dealParamEncrypt(List<Field> fields,Object parameterObject) throws Exception {
        fields.forEach(declaredField->{
            declaredField.setAccessible(true);
            Object o = null;
            try {
                o = declaredField.get(parameterObject);
                declaredField.set(parameterObject,cipherHandler.encrypt(o.toString()));
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        });

    }

    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target,this);
    }

    @Override
    public void setProperties(Properties properties) {

    }

}

查询结果解密

@Intercepts({
        @Signature(type = ResultSetHandler.class, method = "handleResultSets", args = {Statement.class})
})
@Component
public class ResultSetInterceptor implements Interceptor {

    private CipherHandler cipherHandler = AEScipher.getAEScipher();
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        // 取出查询的结果
        Object resultObject = invocation.proceed();
        if (Objects.isNull(resultObject)) {
            return null;
        }
        // 基于selectList
        if (resultObject instanceof List<?>) {
            List<?> resultList = (List<?>) resultObject;
            if (!CommonHelper.isEmpty(resultList)) {
                for (Object obj : resultList) {
                    toDecrypt(obj);
                }
            }
        } else {
            toDecrypt(resultObject);
        }
        return resultObject;
    }

    private void toDecrypt(Object object) throws Exception {
        Class<?> objectClass = object.getClass();
        Field[] declaredFields = objectClass.getDeclaredFields();
        for (Field declaredField : declaredFields) {
            Annotation annotation = declaredField.getAnnotation(Encryption.class);
            if(!CommonHelper.isEmpty(annotation)){
                declaredField.setAccessible(true);
                declaredField.set(object,cipherHandler.decrypt(declaredField.get(object).toString()));
            }
        }
    }

    @Override
    public Object plugin(Object o) {
        return Plugin.wrap(o,this);
    }

    @Override
    public void setProperties(Properties properties) {

    }
}

判空工具类

public class CommonHelper {

    public static boolean isEmpty(Object o){
        if(o==null)return true;
        if(o instanceof String){
          return  ((String) o).isEmpty();
        }else if(o instanceof List){
            return CollectionUtils.isEmpty((List) o) || ((List<?>) o).size()==0 ;
        }else if(o instanceof Map){
            return CollectionUtils.isEmpty((Map) o) || ((Map<?,?>) o).size()==0 ;
        }else {
            return Objects.isNull(o);
        }
    }
}

测试结果：
插入数据

查询数据：