背景

?公司某貸業(yè)務(wù)線同學(xué)某天在針對(duì)aop方法進(jìn)行單測(cè)的時(shí)候遇到問(wèn)題然后有幸?guī)兔σ黄鹋挪閱?wèn)題，報(bào)錯(cuò)的信息翻譯過(guò)來(lái)就是在spring上下文中找不到指定類型的類對(duì)象，具體錯(cuò)誤信息如下。

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type [service.biz.sale.impl.PtXxxCoreServiceImpl] found for dependency: 
expected at least 1 bean which qualifies as autowire candidate for this dependency. 
Dependency annotations: {@javax.annotation.Resource(shareable=true, lookup=, name=, 
description=, authenticationType=CONTAINER, type=class java.lang.Object, mappedName=)}
  at factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1326)
  at factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1072)
  at factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:967)

?額外信息就是在針對(duì)某類增加aop前是沒(méi)有問(wèn)題，但是增加aop之后就會(huì)報(bào)如上錯(cuò)誤，所以基本上第一反應(yīng)就是aop影響了程序的正常啟動(dòng)，只是具體原因不確定而已。

應(yīng)用分析

類的具體實(shí)現(xiàn)方式

• 該類是需要進(jìn)行單測(cè)的類，該類的某方法被aop進(jìn)行了修飾。

• PtXxxCoreServiceImpl的父類BaseSaleXxxService實(shí)現(xiàn)了接口BizSaleXxxService。

• PtXxxCoreServiceImpl繼承自BaseSaleXxxService間接實(shí)現(xiàn)接口。

public abstract class BaseSaleXxxService implements BizSaleXxxService { }

public class PtXxxCoreServiceImpl extends BaseSaleXxxService { }

類的單測(cè)代碼

• 單測(cè)的代碼，通過(guò)在xxxServiceFactory.getCoreService()在spring上線文獲取PtSaleCoreServiceImpl對(duì)象。

• 針對(duì)該對(duì)象的updateXxxCredit進(jìn)行單測(cè)，updateXxxCredit方法通過(guò)aop進(jìn)行切面。

• xxxServiceFactory.getCoreService(XxxChannelEnum.PT.getChannel())獲取PtXxxCoreServiceImpl類型對(duì)象。

• 獲取PtXxxCoreServiceImpl類型對(duì)象報(bào)No qualifying bean of type [PtXxxCoreServiceImpl] found for dependency錯(cuò)誤。

    public void testUpdateXXXCredit() throws Exception {
        try {
            xxxServiceFactory.getCoreService(
                    XxxChannelEnum.PT.getChannel()).updateXxxCredit(111701210L,
                    "200", DateUtil.getNowTimeInSec(),
                    SaleCreditXxxStatusEnum.SUCCESS.getCode());
        } catch (Exception e) {
            throw  e;
        }
    }

AOP的代碼

• 對(duì)PtXxxCoreServiceImpl進(jìn)行了切面操作生成的代理的對(duì)象不再是PtXxxCoreServiceImpl。
• 由于PtXxxCoreServiceImpl實(shí)現(xiàn)了BizSaleXxxService，猜測(cè)最后的代理的對(duì)象應(yīng)該是BizSaleXxxService類型。

@Aspect
public class MonitorXxxService {
    @Before(value = "execution(* service.biz.sale.impl.PtXxxCoreServiceImpl.updateXxxCredit(..))")
    public void salePtCreditMarvin(JoinPoint point) {
    }
}

原因分析

• PtXxxCoreServiceImpl類實(shí)現(xiàn)某個(gè)接口（implements xxxInterface）導(dǎo)致走JDK的代理實(shí)現(xiàn)方式。
• PtXxxCoreServiceImpl的代理對(duì)象類型不再是PtXxxCoreServiceImpl，個(gè)人猜測(cè)為接口xxxInterface類型。
• 通過(guò)JDK生成的代理的類型和類PtXxxCoreServiceImpl不匹配導(dǎo)致報(bào)錯(cuò)該類型的對(duì)象找不到報(bào)錯(cuò)。

spring官網(wǎng)有一段話解釋Spring AOP的具體兩種實(shí)現(xiàn)以及何時(shí)用何種代理實(shí)現(xiàn)。

• 如果代理對(duì)象的類實(shí)現(xiàn)了至少一個(gè)接口（implements interface），那么JDK代理方式會(huì)被使用。
• 如果代理對(duì)象的類沒(méi)有實(shí)現(xiàn)任何接口（implements interface），那么CGLIB代理方式會(huì)被使用。
• 如果你想強(qiáng)制使用CGLIB方式實(shí)現(xiàn)代理，設(shè)置 <aop:config> 標(biāo)簽的proxy-target-class屬性為true即可。

Spring AOP uses either JDK dynamic proxies or CGLIB to create the proxy for a given target object. 
(JDK dynamic proxies are preferred whenever you have a choice).

If the target object to be proxied implements at least one interface then a JDK dynamic proxy will be used. 
All of the interfaces implemented by the target type will be proxied. 
If the target object does not implement any interfaces then a CGLIB proxy will be created.

If you want to force the use of CGLIB proxying, set the value of the 
proxy-target-class attribute of the <aop:config> element to true

<aop:aspectj-autoproxy proxy-target-class="true"/>

解決方案

• 設(shè)置<aop:aspectj-autoproxy proxy-target-class="true"/>使全局都走CGLIB代理方式。

參考

• Aspect Oriented Programming with Spring