Spring Boot 动态创建Bean

1、通过注解@Import导入方式创建

a、新建MyImportBeanDefinitionRegistrar注册中心

import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;

import web0.services.Myservice;


public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {

	protected String BEAN_NAME = "myservice";

	public void dynamicConfiguration() throws Exception {
	}
	
	@Override
	public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
		if (!registry.containsBeanDefinition(BEAN_NAME)) {
			GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
			beanDefinition.setBeanClass(Myservice.class);
			beanDefinition.setSynthetic(true); 
			registry.registerBeanDefinition(BEAN_NAME, beanDefinition);
		}
	}
}

 b、在配置类上加@Import引入上面的类

@Import(MyImportBeanDefinitionRegistrar.class)
public class TestConfig{
}

 c、这样操作后就可以使用spring的方式获取该bean了

 

 

d、使用自定义工厂创建bean

 

public class JdbcPlusBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {

	@Override
	public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {

		AnnotationAttributes annoAttrs = AnnotationAttributes
				.fromMap(importingClassMetadata.getAnnotationAttributes(JdbcMapperScan.class.getName()));

		FastClasspathScanner scanner = new FastClasspathScanner(annoAttrs.getStringArray("value"));
		List<String> classes = scanner.scan().getNamesOfAllClasses();
		for (String className : classes) {
			Class<?> clazz = MethodHandler.initClass(className);
			if (null != clazz) {
				String simpleName = clazz.getSimpleName();
				String beanName = StringUtils.substring(simpleName, 0, 1).toLowerCase()
						+ StringUtils.substring(simpleName, 1);

				if (!registry.containsBeanDefinition(beanName)) {
					
					RootBeanDefinition definition = new RootBeanDefinition(  );
					/*JdbcPlusFactoryBean是spring工厂*/
					definition.setBeanClass( JdbcPlusFactoryBean.class );
					
					ConstructorArgumentValues argumentValues = new ConstructorArgumentValues();
					/*clazz 是要实例化的类*/
					argumentValues.addGenericArgumentValue( clazz );
					
					definition.setConstructorArgumentValues(argumentValues); 
					
					definition.setRole( BeanDefinition.ROLE_INFRASTRUCTURE );
					
					registry.registerBeanDefinition(beanName, definition);  
				}
			}
		}
	}

}

 jdbcplus工厂：

public class JdbcPlusFactoryBean<T> implements FactoryBean<T> {

	protected Class<T> mapperInterface;

	public JdbcPlusFactoryBean() {
	}

	public JdbcPlusFactoryBean(Class<T> mapperInterface) {
		this.mapperInterface = mapperInterface;
	}

	@Override
	public T getObject() throws Exception {
		return MethodProxy.newInstance(mapperInterface) ;
	}

	@Override
	public Class<?> getObjectType() {
		return mapperInterface;
	}

	@Override
	public boolean isSingleton() {
		return true;
	}

}