Spring AOP之异常转换

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!