自定义注解应用（通过@Aspect演示）

墨蓝 2023-07-08 15:25 14阅读 0赞

@Aspect注解pom文件配置

<dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjrt</artifactId>
            </dependency>
            <dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjweaver</artifactId>
            </dependency>

检测到自定义注解修饰的方法被调用时执行

import org.aspectj.lang.JoinPoint;
    import org.aspectj.lang.annotation.Aspect;
    import org.aspectj.lang.annotation.Before;
    import org.aspectj.lang.annotation.Pointcut;
    import org.aspectj.lang.reflect.MethodSignature;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    @Component
    @Aspect
    public class MyLogAspect { 
        private static final Logger logger = LoggerFactory.getLogger(MyLogAspect.class);
    
        /** * 只要用到了MyLog这个注解的，就是目标类 */
        @Pointcut("@annotation(com.example.demo.annotation.test4.MyLog)")
        private void MyValid() { 
        }
    
        @Before("MyValid()")
        public void before(JoinPoint joinPoint) { 
            MethodSignature signature = (MethodSignature) joinPoint.getSignature();
            logger.info("[" + signature.getName() + " : start.....]");
    
            MyLog myLog = signature.getMethod().getAnnotation(MyLog.class);
            logger.info("【目标对象方法被调用时候产生的日志，记录到日志表中】：" + myLog.desc());
        }
    }

自定义注解@MyLog

import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    public @interface MyLog { 
        String desc();
    }

被自定义注解@MyLog修饰的方法LogController

import org.springframework.stereotype.Component;
    
    @Component
    public class LogController { 
    
        @MyLog(desc = "这是结合spring aop知识，讲解自定义注解应用的一个案例")
        public void testLogAspect(){ 
            System.out.println("testLogAspect方法被调用");
        }
    }

@SpringBootTest测试

import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.junit4.SpringRunner;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest
    public class LogControllerTest { 
    
        @Autowired
        private LogController logController;
    
        @Test
        public void testLogAspect() { 
            logController.testLogAspect();
        }
    
    }

注意：  
1.解决shiro与@Aspect冲突的问题，原因未知

<dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjweaver</artifactId>
            </dependency>

2.启动类中未使用注解@EnableAspectJAutoProxy

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    @SpringBootApplication
    public class DemoApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(DemoApplication.class, args);
        }
    }