springboot-自定义Enable*配置注解

素颜马尾好姑娘i 2022-03-21 11:46 296阅读 0赞

1 定义EnableScanner注解，作用是对指定的packages文件夹下的类进行特殊处理，比如设置特殊值等！

package com.cyb.myenable;
    import java.lang.annotation.Documented;
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.annotation.Target;
    
    import org.springframework.context.annotation.Import;
     
    @Target({ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @Import(ScannerPackageRegistrar.class)
    public @interface EnableScanner {
     
        String[] packages();
    }

2 定义注解引入的执行类，并将其注册到spring容器中

package com.cyb.myenable;
 
 import java.util.Arrays;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 /**
 *作者 : iechenyb 
 *类描述: 说点啥 
 *创建时间: 2019年2月1日
 */
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.type.AnnotationMetadata;
 
 public class ScannerPackageRegistrar implements ImportBeanDefinitionRegistrar {
 	Log log = LogFactory.getLog(ScannerPackageRegistrar.class);
 
 	public void registerBeanDefinitions(AnnotationMetadata annotationMetadata,
 			BeanDefinitionRegistry beanDefinitionRegistry) {
 		System.out.println(
 				"packages value::" + annotationMetadata.getAnnotationAttributes(EnableScanner.class.getName()));
 
 		String[] arrs = (String[]) annotationMetadata.getAnnotationAttributes(EnableScanner.class.getName())
 				.get("packages");
 		List<String> packages = Arrays.asList(arrs);
 		System.out.println(packages);
 
 		BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(MyBeanDefinitionProcessor.class);
 		bdb.addPropertyValue("packages", packages);
 
 		beanDefinitionRegistry.registerBeanDefinition(MyBeanDefinitionProcessor.class.getName(),
 				bdb.getBeanDefinition());
 	}
 }

3 定义bean前后置处理器，对指定包里的类进行特殊的初始化。

package com.cyb.myenable;
 import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 /**
 *作者 : iechenyb 
 *类描述: 所有的bean定义时添加前后处理逻辑 
 *创建时间: 2019年2月1日
 */
 public class MyBeanDefinitionProcessor implements BeanPostProcessor{
 	Log log = LogFactory.getLog(MyBeanDefinitionProcessor.class);
 	private List<String> packages;
 	 
 public List<String> getPackages() {
 return packages;
 }
 
 public void setPackages(List<String> packages) {
 this.packages = packages;
 }
 
 public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
 for (String pkg : packages) {
 if(bean.getClass().getName().startsWith(pkg)){
 System.out.println("instance bean:"+bean.getClass().getName());
 }
 }
 return bean;
 }
 
 	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
 		return bean;
 	}
 }

4 定义配置类，启动注解

package com.cyb.myenable;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.context.annotation.Configuration;
 /**
 *作者 : iechenyb 
 *类描述: 说点啥 
 *创建时间: 2019年2月1日
 */
 @Configuration
 @EnableScanner(packages={"com.cyb.adapter","com.cyb.advice"})
 public class ScannerConfiguration {
 	Log log = LogFactory.getLog(ScannerConfiguration.class);
 }