Java aop ComponentScan不工作&AnnotationConfigApplicationContext getBean不工作

Question

我编写了一组简单的类，向一位朋友演示如何为AOP（而不是xml配置）使用注释。我们无法使@ComponentScan工作，并且AnnotationConfigApplicationContext getBean的行为也不正常。我想明白两件事。请参阅下面的代码：

PersonOperationSI.java

package samples.chapter3;

import org.springframework.stereotype.Component;

@Component
public interface PersonOperationsI {

    public String getName();

}

PersonOperations.java

/**
 * 
 */
package samples.chapter3;

import org.springframework.stereotype.Component;

@Component
public class PersonOperations implements PersonOperationsI {


    public String getName() {
        return "";
    }

}

PersonOperationsConfigClass.java

package samples.chapter3;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

@Configuration
//question2  - Below Component Scan didnt work - Test Case failing in setup()
//@ComponentScan(basePackages = {"samples.chapter3"})
@EnableAspectJAutoProxy

public class PersonOperationsConfigClass {

}

PersonOperationsAdvice.java

/**
 * 
 */
package samples.chapter3;

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

@Component
@Aspect
public class PersonOperationsAdvice {

    /**
     * execution( [Modifiers] [ReturnType] [FullClassName].[MethodName]
    ([Arguments]) throws [ExceptionType])

     * @param joinPoint
     * @return
     */
    @Before("execution(public * samples.chapter3.PersonOperations.getName()))")
    public String beforeGetName(JoinPoint joinPoint) {
        System.out.println("method name = " + joinPoint.getSignature().getName());
        return null;
    }
}

PersonOperationStest.java

package samples.chapter3;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit.jupiter.SpringExtension;

@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes = { PersonOperationsConfigClass.class })
public class PersonOperationsTest {

    //@Autowired
    private PersonOperationsI obj;

    @Before
    public void setUp() {

        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
        ctx.scan("samples.chapter3");
        ctx.refresh();
        obj = ctx.getBean(PersonOperationsI.class);
//obj = ctx.getBean(PersonOperations.class);//getBean of Child class not working - why ?

        Assert.assertNotNull(obj);
        ctx.close();
    }

    @Test
    public void test() {
        System.out.println(obj.getName());
    }

}

Answer 1

>

通常您应该使用@componentscan以及@configuration注释类，并记住@componentscan不带参数会告诉Spring扫描当前包及其所有子包。

@Component类告诉Spring创建一个这种类型的bean，这样您就不再需要使用xml配置，并且这个bean是一个可以实例化的类=>no interface/abstract classes。因此，在您的情况下，应该从PersonOperationSI中删除@组件，并将其仅保留在PersonOperation中。当您用@component注释类时，给bean的默认名称是首字母较低的类名，因此您应该调用ctx.getBean（“PersonOperationSI”）或ctx.getBean(PersonOperations.class)

以后阅读这些接口和实现的命名约定。在您的情况下，我将修改以下内容:PersonOperationSI为Operation