Spring-AOP之异常转换

引子

最近项目遇到了一个问题，就是说业务层向展现层需要转换成统一个异常类，并抛出异常，但是由于业务层的异常类过多，所以导致业务异常转换代码充斥着异常转换的代码，本着程序猿能省写代码就省写代码的原则，决定用Spring AOP来做一个切片，业务异常类转换.

最原始代码

最原始的代码，咱简称V1.0

 @Override

    public GnAreaVo selectByID(GnAreaCondition condition) throws CallerException {

        try {

            //业务处理

            if (StringUtils.isEmpty(condition.getAreaCode()))

                throw new BusinessException("10001", "区域编码不能为空");

            Gson gson = new Gson();

            //处理结果

            return gson.fromJson(gson.toJson(iGnAreaBusinessService.selectByID(condition.getAreaCode())), GnAreaVo.class);

        } catch (BusinessException ex) {

            //

            throw new CallerException("100001", ex.getErrorMessage());

        } catch (SystemException ex) {

            //

            throw new CallerException("100001", ex.getMessage());

        } catch (Exception ex) {

            //

            throw new CallerException("10001", "系统异常");

        }

    }

升级版本

升级版本，简称V1.1，提取出一个公共类来处理

@Override

    public GnAreaVo selectByID(GnAreaCondition condition) throws CallerException {

        try {

            //业务处理

            if (StringUtils.isEmpty(condition.getAreaCode()))

                throw new BusinessException("10001", "区域编码不能为空");

            Gson gson = new Gson();

            //处理结果

            return gson.fromJson(gson.toJson(iGnAreaBusinessService.selectByID(condition.getAreaCode())), GnAreaVo.class);

        } catch (BusinessException ex) {

            //

            throw DubboExceptAssembler.assemble(ex);

        } catch (SystemException ex) {

            //

            throw DubboExceptAssembler.assemble(ex);

        } catch (Exception ex) {

            //

            throw DubboExceptAssembler.assemble(ex);

        }

    }

最终版

代码更加简单了，并且能支持更加多异常类的转换，减少业务程序的无用代码，下面来看看怎么实现的。
首先写一个AOP

import com.ai.runner.base.exception.BusinessException;

import com.ai.runner.base.exception.SystemException;

import com.ai.runner.utils.util.DubboExceptAssembler;

import org.apache.logging.log4j.LogManager;

import org.apache.logging.log4j.Logger;

import org.aspectj.lang.JoinPoint;

public class DubboExceptionConvertInterceptor {

    private static final Logger logger = LogManager.getLogger(DubboExceptionConvertInterceptor.class);

    public void convertException(JoinPoint joinPoint, Exception error) {

        logger.error("执行{}类中的{}方法出错，出错原因:{}", joinPoint.getTarget().getClass().getName(),

                joinPoint.getSignature().getName());

        if (error instanceof SystemException) {

            throw DubboExceptAssembler.assemble((SystemException) error);

        }

        if (error instanceof BusinessException) {

            throw DubboExceptAssembler.assemble((BusinessException) error);

        }

        throw DubboExceptAssembler.assemble(error);

    }

}

Spring的配置：

<bean id="dubboExceptionConvertor" class="DubboExceptionConvertInterceptor"/>

    <aop:config>

        <aop:aspect id="aspectLoggging" ref="dubboExceptionConvertor">

            <aop:pointcut id="dubboExceptionThrowing"

                          expression="execution (* com.ai.runner.center.common.api.*.impl.*.*(..))"/>

            <aop:after-throwing method="convertException" throwing="error"

                                pointcut-ref="dubboExceptionThrowing"/>

        </aop:aspect>

    </aop:config>

业务代码：

  @Override

    public GnAreaVo selectByID(GnAreaCondition condition) throws CallerException {

        if (StringUtils.isEmpty(condition.getAreaCode()))

            throw new BusinessException("10001", "区域编码不能为空");

        Gson gson = new Gson();

        return gson.fromJson(gson.toJson(iGnAreaBusinessService.selectByID(condition.getAreaCode())), GnAreaVo.class);

    }

Done!