AOP学习续

@Aspect:作用是把当前类标识为一个切面供容器读取
@Pointcut：Pointcut是植入Advice的触发条件。每个Pointcut的定义包括2部分，一是表达式，二是方法签名。方法签名必须是 public及void型。可以将Pointcut中的方法看作是一个被Advice引用的助记符，因为表达式不直观，因此我们可以通过方法签名的方式为 此表达式命名。因此Pointcut中的方法只需要方法签名，而不需要在方法体内编写实际代码。
@Around：环绕增强，相当于MethodInterceptor
@AfterReturning：后置增强，相当于AfterReturningAdvice，方法正常退出时执行
@Before：标识一个前置增强方法，相当于BeforeAdvice的功能，相似功能的还有
@AfterThrowing：异常抛出增强，相当于ThrowsAdvice
@After: final增强，不管是抛出异常或者正常退出都会执行

1. 使用pointcut代码：

import java.util.Arrays;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AdviceTest {
@Around(“execution( com.abc.service..many(..))”)
public Object process(ProceedingJoinPoint point) throws Throwable {
System.out.println(“@Around：执行目标方法之前…”);
//访问目标方法的参数：
Object[] args = point.getArgs();
if (args != null && args.length > 0 && args[0].getClass() == String.class) {
args[0] = “改变后的参数1”;
}
//用改变后的参数执行目标方法
Object returnValue = point.proceed(args);
System.out.println(“@Around：执行目标方法之后…”);
System.out.println(“@Around：被织入的目标对象为：” + point.getTarget());
return “原返回值：” + returnValue + “，这是返回结果的后缀”;
}

@Before(“execution( com.abc.service..many(..))”)
public void permissionCheck(JoinPoint point) {
System.out.println(“@Before：模拟权限检查…”);
System.out.println(“@Before：目标方法为：” +
point.getSignature().getDeclaringTypeName() +
“.” + point.getSignature().getName());
System.out.println(“@Before：参数为：” + Arrays.toString(point.getArgs()));
System.out.println(“@Before：被织入的目标对象为：” + point.getTarget());
}

@AfterReturning(pointcut=”execution( com.abc.service..many(..))”,
returning=”returnValue”)
public void log(JoinPoint point, Object returnValue) {
System.out.println(“@AfterReturning：模拟日志记录功能…”);
System.out.println(“@AfterReturning：目标方法为：” +
point.getSignature().getDeclaringTypeName() +
“.” + point.getSignature().getName());
System.out.println(“@AfterReturning：参数为：” +
Arrays.toString(point.getArgs()));
System.out.println(“@AfterReturning：返回值为：” + returnValue);
System.out.println(“@AfterReturning：被织入的目标对象为：” + point.getTarget());

}

@After(“execution( com.abc.service..many(..))”)
public void releaseResource(JoinPoint point) {
System.out.println(“@After：模拟释放资源…”);
System.out.println(“@After：目标方法为：” +
point.getSignature().getDeclaringTypeName() +
“.” + point.getSignature().getName());
System.out.println(“@After：参数为：” + Arrays.toString(point.getArgs()));
System.out.println(“@After：被织入的目标对象为：” + point.getTarget());
}
}

1. 使用annotation代码：

import java.lang.annotation.ElementType;import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.METHOD })
public @interface SMSAndMailSender {
/短信模板String格式化串/
String value() default “”;

String smsContent() default “”;

String mailContent() default “”;
/是否激活发送功能/
boolean isActive() default true;
/主题/
String subject() default “”;
}



//切面类
@Aspect
@Component(“smsAndMailSenderMonitor”)
public class SMSAndMailSenderMonitor {

private Logger logger = LoggerFactory.getLogger(SMSAndMailSenderMonitor.class);


/
在所有标记了@SMSAndMailSender的方法中切入
@param joinPoint
@param result
/
@AfterReturning(value=”@annotation(com.trip.demo.SMSAndMailSender)”, returning=”result”)//有注解标记的方法，执行该后置返回
public void afterReturning(JoinPoint joinPoint , Object result//注解标注的方法返回值) {
MethodSignature ms = (MethodSignature) joinPoint.getSignature();
Method method = ms.getMethod();
boolean active = method.getAnnotation(SMSAndMailSender.class).isActive();
if (!active) {
return;
}
String smsContent = method.getAnnotation(SMSAndMailSender.class).smsContent();
String mailContent = method.getAnnotation(SMSAndMailSender.class).mailContent();
String subject = method.getAnnotation(SMSAndMailSender.class).subject();

}



/
在抛出异常时使用
@param joinPoint
@param ex
/
@AfterThrowing(value=”@annotation(com.trip.order.monitor.SMSAndMailSender)”,throwing = “ex”)
public void afterThrowing(JoinPoint joinPoint, Throwable ex//注解标注的方法抛出的异常) {
MethodSignature ms = (MethodSignature) joinPoint.getSignature();
Method method = ms.getMethod();
String subject = method.getAnnotation(SMSAndMailSender.class).subject();

}

}


//实体类中使用该注解标注方法
@Service(“testService “)
public class TestService {


@Override
@SMSAndMailSender(smsContent = “MODEL_SUBMIT_SMS”, mailContent =
“MODEL_SUPPLIER_EMAIL”, subject = “MODEL_SUBJECT_EMAIL”)
public String test(String param) {
return “success”;
}
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