Spring AOP及MethodInterceptor拦截器实现方法拦截以及切入点函数阻止执行

迈不过友情╰ 2022-07-15 06:16 154阅读 0赞

**声明：本博文用于学习总结及工作心得**

项目中需要修改IM信息送以及短信发送，要求已离职的人员不呢收到IM信息和短信

因为在项目中各个地方都有使用到短信和IM信息通知;所以想到使用Spring AOP进行实现，以及拦截器进行实现，一下为两种方法的具体实现代码:  
1)Spsing AOP

<table> 需要被织入的切面类: 
 <tbody> 
 <tr> 
 <td>ppackage com.xxx.utils; import com.xxx.bean_new.personnel.Employee; import com.xxx.bean_new.personnel.User; import com.xxx.dao_new.EmployeeDAO; import com.xxx.dao_new.UserDAO; import org.aspectj.lang.JoinPoint; import org.aspectj.lang.ProceedingJoinPoint; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Before; /** &nbsp;* Created by Administrator on 2016/11/4 0004. &nbsp;*/ //声明这是一个切面Bean @Aspect public class SendMsgAspect { &nbsp; &nbsp; @Before("execution(* com.xxx.pushMsg.PushMsg.sendMsg(..))") &nbsp; &nbsp; Object before(JoinPoint joinPoint) { &nbsp; &nbsp; &nbsp; &nbsp; Object[] args = joinPoint.getArgs(); &nbsp; &nbsp; &nbsp; &nbsp; try { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (args.length &gt;= 2) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; String IMAccount = (String) args[2]; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; UserDAO userDAO = (UserDAO) Utils.getBean("userDAO"); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (null != userDAO) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; User user = userDAO.getUsersByIMAccount(IMAccount); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (null != user) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; EmployeeDAO employeeDAO = (EmployeeDAO) Utils.getBean("employeeDAO"); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Employee employee = employeeDAO.get(user.getEmployeeId()); //这里进行业务逻辑判断 通过IMAcount信息获取到员工,如果该员工状态为离职，则将IMAcount修改空也就是args[2];并且抛出异常 由try{}catch捕捉该异常 //否则不做任何操作，直接返回 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (employee == null || employee.getEntry() == null || employee.getEntry().getStatus() == null || "离职".equals(employee.getEntry().getStatus())) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; args[2] = ""; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; throw new RuntimeException(employee.getName() + "：该员工已离职通知失败!"); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; } catch (Exception e) { &nbsp; &nbsp; &nbsp;//扑捉到异常后 pjp.proceed(args)将args 也就是修改后的参数传给目标函数 这里的目标函数是指被切入点的函数 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;//需要注意的是,如果是使用了pjp.proceed(args) 目标函数会被执行两次 正是因为这点 所以接着写了另一个具有相同功能的拦截器 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ProceedingJoinPoint pjp = (ProceedingJoinPoint) joinPoint; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Object retVal = null; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; try { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; retVal = pjp.proceed(args); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } catch (Throwable throwable) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; throwable.printStackTrace(); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return retVal; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; return null; &nbsp; &nbsp; } }</td> 
 </tr> 
 </tbody> 
</table>

<table> applicationContext.xml配置文件修改 
 <tbody> 
 <tr> 
 <td>配置文件中添加以下内容： &lt;bean id="sendMsgAop" class="com.xxx.utils.SendMsgAspect"&gt; &lt;/bean&gt; &lt;aop:config&gt; &lt;!-- 定义切点 --&gt; &lt;aop:pointcut id="aroundPointcutTarget" &nbsp;expression="execution(* com.xxx.pushMsg.PushMsg.sendMsg(..))"/&gt; &lt;!-- 定义切面 --&gt; &lt;aop:aspect id="userAspect" ref="sendMsgAop"&gt; &lt;!--通知函数 method 的参数为 ProceedingJoinPoint 类型 该类型为 JoinPoint 的子类 可以通过该对象获取 被切面参数 以及 返回值--&gt; &lt;aop:before method="before" pointcut-ref="aroundPointcutTarget"/&gt; &lt;!--&lt;aop:around method="checkEntrystatus" pointcut-ref="aroundPointcutTarget"/&gt;--&gt; &lt;/aop:aspect&gt; &lt;/aop:config&gt;</td> 
 </tr> 
 </tbody> 
</table>

2)MethodInterceptor拦截器

<table> 拦截器类 
 <tbody> 
 <tr> 
 <td>package com.xxx.utils; import com.xxx.bean_new.personnel.Employee; import com.xxx.bean_new.personnel.User; import com.xxx.dao_new.EmployeeDAO; import com.xxx.dao_new.UserDAO; import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; import java.lang.reflect.Method; /** &nbsp;* Created by Administrator on 2016/11/5 0005. &nbsp;*/ public class SendMsgInterceptor implements MethodInterceptor { &nbsp; &nbsp; @Override &nbsp; &nbsp; public Object invoke(MethodInvocation invo) throws Throwable { &nbsp; &nbsp; &nbsp; &nbsp; Object[] args = invo.getArguments(); &nbsp; &nbsp; &nbsp; &nbsp; Method method = invo.getMethod(); &nbsp; &nbsp; &nbsp; &nbsp; if (!"sendMsg".equals(method.getName())) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Object obj = invo.proceed(); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return obj; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; try { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (args.length &gt;= 2) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; String IMAccount = (String) args[2]; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; UserDAO userDAO = (UserDAO) Utils.getBean("userDAO"); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (null != userDAO) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; User user = userDAO.getUsersByIMAccount(IMAccount); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (null != user) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; EmployeeDAO employeeDAO = (EmployeeDAO) Utils.getBean("employeeDAO"); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Employee employee = employeeDAO.get(user.getEmployeeId()); //业务逻辑判断 通过IMAcount信息获取到员工,如果该员工状态不为离职的情况下，通过&nbsp;invo.proceed();它来对目标对象方法调用，返回一个Object对象。 //否则不做任何操作，直接返回 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (employee != null &amp;&amp; employee.getEntry() != null &amp;&amp; employee.getEntry().getStatus() != null &amp;&amp; !"".equals(employee.getEntry().getStatus())) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Object obj = invo.proceed(); &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return obj; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; } catch (Exception e) { &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace(); &nbsp; &nbsp; &nbsp; &nbsp; } &nbsp; &nbsp; &nbsp; &nbsp; return args; &nbsp; &nbsp; } }</td> 
 </tr> 
 </tbody> 
</table>

<table> applicationContext.xml配置文件修改 
 <tbody> 
 <tr> 
 <td>&lt;bean id="myInterceptor" &nbsp;class="com.xxx.utils.SendMsgInterceptor" &nbsp;abstract="false" lazy-init="default" &nbsp;autowire="default"&gt; &lt;/bean&gt; &lt;!--这里需要注意如果是使用接口的话 这里需要这样定义--&gt; &lt;!--&lt;bean id="bean" class="org.springframework.aop.framework.ProxyFactoryBean"&gt; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;property name="proxyInterfaces"&gt; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;value&gt;aop.Interface&lt;/value&gt; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &lt;/property&gt; &lt;property name="interceptorNames"&gt; &lt;list&gt; &lt;value&gt;myInterceptor&lt;/value&gt; &lt;/list&gt; &lt;/property&gt; &lt;/bean&gt;--&gt; &lt;!--方法--&gt; &lt;!--&lt;bean class="org.springframework.aop.support.NameMatchMethodPointcutAdvisor"&gt;--&gt; &lt;!--&lt;property name="mappedNames"&gt;--&gt; &lt;!--&lt;list&gt;--&gt; &lt;!--&lt;value&gt;send*&lt;/value&gt;&amp;lt;!&amp;ndash; 所有方法 &amp;ndash;&amp;gt;--&gt; &lt;!--&lt;/list&gt;--&gt; &lt;!--&lt;/property&gt;--&gt; &lt;!--&lt;property name="advice"&gt;--&gt; &lt;!--&lt;ref local="myInterceptor"/&gt;--&gt; &lt;!--&lt;/property&gt;--&gt; &lt;!--&lt;/bean&gt;--&gt; &lt;bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator"&gt; &lt;property name="beanNames"&gt; &lt;!--PushMsg类可以使用注解 或者手动加入到配置文件--&gt; &lt;list&gt;&lt;value&gt;pushMsg&lt;/value&gt;&lt;/list&gt; &lt;/property&gt; &lt;property name="interceptorNames"&gt; &lt;list&gt; &lt;value&gt;myInterceptor&lt;/value&gt; &lt;/list&gt; &lt;/property&gt; &lt;/bean&gt;</td> 
 </tr> 
 </tbody> 
</table>

第二种不会造成目标函数第二次执行