SpringAOP 引介切面

引介切面是一种比较特殊的增强类型，它不是在目标方法周围织入增强，而是为目标类创建新的方法和属性，所以引介增强的链接点是类级别的，而非方法级别的。通过引介增强，我们可以为一个目标类添加一个接口实现。即原来的目标类未实现某个接口，通过引介增强可以为目标类创建某个接口代理。这种功能富有吸引力，因为他能够在横向定义接口实现的方法。思考问题的角度发生了很大的变化。这也是切面编程魅力所在！！！- o -。

 
/**要侵入的接口*/
package com.book.service;
  
public interface Monitorable {
  public void setMonitorActive(Boolean flage);
}
  
  
package com.book.serviceImpl;
  
import com.book.entity.User;
/**目标类*/
public class UserServiceImpl {
  
    public User findByName(String name) {
        // TODO Auto-generated method stub
        System.out.println("进入了service层了哦!!!");
        return new User(name,"26");
    }
   
}
  
  
/**增强*/
package com.book.aop;
  
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.aop.support.DelegatingIntroductionInterceptor;
  
import com.book.service.Monitorable;
  
public class PerformanceMonitor extends DelegatingIntroductionInterceptor implements Monitorable{
   private  ThreadLocal<Boolean> laosn=new ThreadLocal<Boolean>();
    public void setMonitorActive(Boolean flage) {
        // TODO Auto-generated method stub
        laosn.set(flage);
    }
      
    public Object   invoke(MethodInvocation mi) throws Throwable{
        Object obj=null;
        if(laosn.get()!=null&&laosn.get()){
            System.out.println("-------------哈哈!骚年!你被织入了接口了----------开始-----");
            obj=super.invoke(mi);
            System.out.println("-------------哈哈!骚年!你被织入了接口了----------结束-----");
        }else {
            obj=super.invoke(mi);
        }
        return obj;
  
    }
  
}
  
@Controller
public class TianController {
  
 @Resource(name="userServiceProxyfactorybean")
 private UserServiceImpl userServiceProxyfactorybean;
  
    @RequestMapping("/tian2")
    public String tian2(){
          /**转换成侵入接口然后再调用接口方法改变行为*/
        Monitorable mo=(Monitorable)userServiceProxyfactorybean;
        mo.setMonitorActive(true);
        User user=proxyfactorybean.findByName("zhangtian");
          
        return "user/index";
    }
}
  
  
/**最后配置applicationContext.xml*/
  
  <!-- 此配置演示了 引介切点 -->
      
    <bean id="performancemonitoradvice" class="com.book.aop.PerformanceMonitor"></bean>
    <bean id="userserviceTarget" class="com.book.serviceImpl.UserServiceImpl"></bean>
    <bean id="userServiceProxyfactorybean"  p:interfaces="com.book.service.Monitorable"    p:interceptorNames="performancemonitoradvice"  p:target-ref="userserviceTarget"   p:proxyTargetClass="true"class="org.springframework.aop.framework.ProxyFactoryBean"/>