需求：

        针对查询返回的数据，在数据库层处理可能会影响到性能，在考虑性能及维护方便的情况下，采用AOP实现

1，自定义注解

import java.lang.annotation.*;/*** 针对 mapper层返回值 按照一定规则进行特殊处理后返回*/
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface MapperReturnData {/*** 指定执行规则的方法，默认方法为：transferReturnData* @return*/String method() default "transferReturnData";Class<? extends MapperReturnDataInterface> operation();
}

2，定义公共业务处理接口

/*** 不同的业务场景 其 针对返回值 解析处理规则不同，须根据自身情况实现该接口* @param <T>*/
public interface MapperReturnDataInterface<R> {R transferReturnData(Object request);}

3，编写AOP核心实现

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;/*** 针对 mapper层返参进行特殊处理*/
@Component
@Aspect
public class MapperReturnDataAspect {private static final Logger log = LoggerFactory.getLogger(MapperReturnDataAspect.class);//定义pointcut签名@Pointcut("execution(* com.taia.yms.mapper.*.*(..)) && @annotation(com.taia.yms.aop.reponse.MapperReturnData)")private void pointCut() {//方法为空，仅做签名}//对切点方法进行前置增强，就是在调用切点方法前进行做一些必要的操作，这就成为增强@Around("pointCut()")public Object getRes(ProceedingJoinPoint joinPoint) throws Throwable {// 获取被拦截的方法签名MethodSignature signature = (MethodSignature) joinPoint.getSignature();// 获取被拦截的方法Method method = signature.getMethod();// 获取返回值Object returnObj = joinPoint.proceed();MapperReturnData annotation = method.getAnnotation(MapperReturnData.class);// 查找并获取注解try{// 读取注解的属性Class<? extends MapperReturnDataInterface> operation = annotation.operation();MapperReturnDataInterface operationInstance = operation.getDeclaredConstructor().newInstance();String methoded = annotation.method();Method operationMethod = operation.getDeclaredMethod(methoded, Object.class);return operationMethod.invoke(operationInstance,returnObj);}catch (Exception e){log.error("类[{}]的方法[{}]执行失败，报错:{}",annotation.operation().getName(),annotation.method(),e.getMessage());return returnObj;}}}

4，编写业务处理实现

import org.springframework.util.CollectionUtils;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;public class TechnologyGetDataTypeList implements MapperReturnDataInterface<List<String>>{@Overridepublic List<String> transferReturnData(Object request) {List<String> list = (List<String>) request;if(CollectionUtils.isEmpty(list)){return new ArrayList<>(1);}List<String> results = list.stream().map(v -> v.substring(v.indexOf("_")+1)).collect(Collectors.toList());return results;}
}

5，在mapper指定接口方法上使用

    @MapperReturnData(operation = TechnologyGetDataTypeList.class)List<String> getDataTypeList(List<String> columnList);