春季AOP无需@EnableAspectJAutoProxy即可工作？

java spring spring-aop aspectj

2022-09-01 13:04:45

我正在学习Spring（目前是它的AOP框架）。尽管我读过的所有源代码都说要启用AOP，需要使用注释（或其XML对应物），但我的代码似乎可以使用注释注释。这是因为我使用的是龙目岛还是Spring Boot（v. 1.5.9.RELEASE，依赖于Spring v. 4.3.13.RELEASE）？@EnableAspectJAutoProxy

最小示例如下：

build.gradle

buildscript {
    ext {
        springBootVersion = '1.5.9.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'java'
apply plugin: 'org.springframework.boot'

group = 'lukeg'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}


dependencies {
    compile('org.springframework.boot:spring-boot-starter')
    compileOnly('org.projectlombok:lombok')
    compile("org.aspectj:aspectjweaver:1.8.11")
    testCompile('org.springframework.boot:spring-boot-starter-test')
}

应用程序配置.java（请注意，AOP 批注已注释掉）

package lukeg;

import org.springframework.context.annotation.*;

@Configuration
@ComponentScan
//@EnableAspectJAutoProxy
public class ApplicationConfiguration {
    @Bean
    TestComponent testComponent() {
        return new TestComponent();
    }
}

学习应用.java

package lukeg;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

@SpringBootApplication
public class LearnApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(LearnApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {
        ApplicationContext context = new AnnotationConfigApplicationContext(ApplicationConfiguration.class);
        TestComponent testComponent = context.getBean(TestComponent.class);
        System.out.println(""+testComponent);
    }
}

伐木工.java

package lukeg;

import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class LoggerHogger {

    @Pointcut("execution(* lukeg*.*.toString(..))")
    public void logToString() {}

    @Before("logToString()")
    public void beforeToString () {
        System.out.println("Before toString");
    }
}

测试组件.java

package lukeg;

import lombok.Data;


@Data
public class TestComponent {
}

答案 1

批注包含批注。这种自动配置是Spring Boot的吸引力之一，使配置更简单。自动配置使用类型注释（如和）来扫描类路径并查找触发加载“模块”（如AOP）的关键类。@SpringBootApplication@EnableAutoConfiguration@Conditional@ConditionalOnClass@ConditionalOnProperty

下面是一个示例 AopAutoConfiguration.java

import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.Advice;
import org.aspectj.weaver.AnnotatedElement;

@Configuration
@ConditionalOnClass({ EnableAspectJAutoProxy.class, Aspect.class, Advice.class,
    AnnotatedElement.class })
@ConditionalOnProperty(prefix = "spring.aop", name = "auto", havingValue = "true", matchIfMissing = true)
public class AopAutoConfiguration {

  @Configuration
  @EnableAspectJAutoProxy(proxyTargetClass = false)
  @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "false", matchIfMissing = false)
  public static class JdkDynamicAutoProxyConfiguration {

  }

  @Configuration
  @EnableAspectJAutoProxy(proxyTargetClass = true)
  @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true", matchIfMissing = true)
  public static class CglibAutoProxyConfiguration {

  }

}

如您所见，如果将上述 aop 类之一添加到类路径（或属性）中，Spring 将检测到它并有效地运行，就好像您在主类上进行了@EnableAspectJAutoProxy注释一样。

您的项目有一个文件LoggerHogger，它有一个@Aspect。

答案 2