Spring BOOT AOP基础应用教程

 Proxy.newProxyInstance(Main.Class.getClassLoader(), new Class[] {UserDao.class}, new InvocationHandler() {
})
//在 InvocationHandler()  调用方法之前增强添加预处理 和 方法调用后的处理东西

public interface UserDao {
    public int add(int a, int b);
}
public class UserDaoImpl implements UserDao {
    @Override
    public int add(int a, int b) {
        System.out.println("add 方法执行了");
        return a+b;
    }
}
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
public class Main {
    public static void main(String[] args) {
        Class[] interfaces = {UserDao.class};
        UserDaoImpl userDaoImpl = new UserDaoImpl();
        //创建接口实现类代理对象
        //此处用UserDao作为返回值的类型，是因为我们传入的interfaces就是UserDao.class
        UserDao dao = (UserDao) Proxy.newProxyInstance(Main.class.getClassLoader(), interfaces, new InvocationHandler() {
            //把想要代理的对象传递进来
            private Object object = userDaoImpl;
            //增强的逻辑
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                //方法之前
                System.out.println("方法之前执行 : " + method.getName() + "; 传递的参数：" + Arrays.toString(args) + "; object:" + object);
                //被增强的方法执行，填写要增强的对象、参数
                Object res = method.invoke(object, args);
                //方法之后
                System.out.println("方法之后执行 : " + method.getName() + "; 传递的参数：" + Arrays.toString(args) + "; object:" + object);

                return res;
            }
        });
        int res = dao.add(1, 2);
        System.out.println("这个是res: " + res);
    }
}

@Component
@Aspect
public class BookAop {
    // 定义切入点
    public static final String POINT_CUT = "execution(* com.example.bootaop.dao..*.*(..))";
    @Before(POINT_CUT)
    public void before() {
        System.out.println("----------添加图书方法前[校验]-----------");
    }
    @After(POINT_CUT)
    public void after(JoinPoint jp) {
        System.out.println("----------添加图书成功后-----------");
        System.out.println(jp.getTarget().getClass());
        System.out.println(Arrays.asList(jp.getArgs()));
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface MyLog {
    String value() default "";
}

@Slf4j
@Aspect
@Component
public class LogAspect {
    @Around("@annotation(myLog)")
    public Object around(ProceedingJoinPoint point, MyLog myLog) throws Throwable{
        String className = point.getTarget().getClass().getName();
        String methodName = point.getSignature().getName();
        String value = myLog.value();
        log.info("类名：{}，方法名：{}，注解值：{}",className,methodName,value);
        log.info("方法之前执行");
        long startTime = System.currentTimeMillis();
        Object proceed = point.proceed();
        long endTime = System.currentTimeMillis();
        long time = endTime - startTime;
        log.info("方法之后执行");
        log.info("方法耗时：{}", time);
        return proceed;
    }
}