AOP切面编程后置通知实现返回值的判空值处理（项目中使用）-蒲公英云

AOP切面编程后置通知实现返回值的判空值处理（项目中使用）

目的：因为根据平常的代码在service层根据返回值要做判断空值处理，抛对应的错误信息，得每个方法判断一次，比较麻烦。现在的处理方法是根据放回值类型判断是否list.class，是的话list.size（）=0抛对应的错误信息，然后在判断是否int.class等，希望能给大家代理帮助。

平常的代码写法

if(i==0){
    throw new AppcationException(ExceptionEnum.DELETEDATADEFEAIED);
}

错误类的种类

INSERTDATADEFEATED(1001,"数据插入失败,"),
NOTFOUNTVALUE(1002,"找不到对应的值"),
UPDATEDATADEFEAIED(1003,"更新数据失败"),
DElETEDATADEFEAIED(1004,"更新数据失败");

现在的写法

注意：1.

Class returnType = ((MethodSignature) signature).getReturnType();

Api地址：

http://www.eclipse.org/aspectj/doc/released/runtime-api/org/aspectj/lang/reflect/MethodSignature.html\#getReturnType()

获取返回值类型

2.先判断list.class，int.class然后看是否是get或select开头的。

因为正规的话select开头返回object，get开头返回list，由于大家把两个闹乱了所以做了一下改造，测试通过。

@Aspect
@Component
public class ExceptionInterceptor {
    protected Logger log = (Logger) Logger.getLogger(this.getClass());
    /**
     * select开头  返回值为object
     * get开头  返回值为list
     * updat  返回值为int
     * delete开头  返回值为int
     * insert  返回值为int
     */
    @AfterReturning(value = "execution(* com.lenovo.pcsd.bp.businesspartner.mapper.*.*(..))", returning = "result")
    @SuppressWarnings("unchecked")
    public void afterReturning(JoinPoint joinPoint, Object result) {
        Signature signature = joinPoint.getSignature();
        String methodName = signature.getName();
        String selectregex = "^select.*$";
        String getregex = "^get.*$";
        String updateregex = "^updat.*$";
        String deleteregex = "^delete.*$";
        String insertregex = "^insert.*$";
        Class returnType = ((MethodSignature) signature).getReturnType();
        Pattern selectp = Pattern.compile(selectregex);
        Pattern getp = Pattern.compile(getregex);
        Pattern updatp = Pattern.compile(updateregex);
        Pattern deletep = Pattern.compile(deleteregex);
        Pattern insertp = Pattern.compile(insertregex);
        if (returnType.equals(List.class)) {
            List<? extends Object> list = (ArrayList<T>) result;
            if (list.size() == 0) {
                throw new AppcationException(ExceptionEnum.NOTFOUNTVALUE);
            }
        } else if (returnType.equals(Integer.class)) {
            Integer taskList = (Integer) result;
            if (taskList == 0) {
                if (updatp.matcher(methodName).matches()) {
                    throw new AppcationException(ExceptionEnum.UPDATEDATADEFEAIED);
                } else if (deletep.matcher(methodName).matches()) {
                    throw new AppcationException(ExceptionEnum.DElETEDATADEFEAIED);
                } else if (insertp.matcher(methodName).matches()) {
                    throw new AppcationException(ExceptionEnum.INSERTDATADEFEATED);
                }
            }
        } else {
            if (StringUtils.isEmpty(result)) {
                if (getp.matcher(methodName).matches() || selectp.matcher(methodName).matches()) {
                    throw new AppcationException(ExceptionEnum.NOTFOUNTVALUE);
                }
            }
        }
    }
}