1、通过xml
2、通过注解@Component及其衍生注解@Controller、@Service、@Repository定义bean
例子：
@Component
public void Car{
}
3、使用@Configuration定义成一个配置类
@Configuration
public void Car{
}
4、实现FactoryBean
例子：
public class Car {
}
public class CarFactoryBean implements FactoryBean<Car> {
@Override
public Car getObject() throws Exception {
Car car = new Car();
//创建这个bean前，在这边可以自定义处理一些业务逻辑
return car;
}
@Override
public Class<?> getObjectType() {
return Car.class;
}
@Override
public boolean isSingleton() {
return FactoryBean.super.isSingleton();
}
}
@Configuration
public class SpConfig {
@Bean
public CarFactoryBean car(){
return new CarFactoryBean();
}
}
5、加载配置类并加载配置文件
例子：
public class Car {
}
app.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="car" class="com.melax.ailatest.bean.Car"></bean>
</beans>
@Configuration
@ImportResource("app.xml")
public class SpConfig2 {
}
6、使用@Import注解方式导入，被导入的bean无需使用注解申明为bean
public class Car {
}
@Import({Car.class})
public class SpConfig3 {
}
7、导入实现了ImportSelector接口的类，实现了对导入源的编程时处理
示例：
public class Car {
}
public class MyImportSelector implements ImportSelector {
@Override
public String[] selectImports(AnnotationMetadata importingClassMetadata) {
//各种条件判断
boolean b = importingClassMetadata.hasAnnotation("org.springframework.context.annotation.Import");
System.out.println("flag:"+b);
if (b){
return new String[]{"com.melax.ailatest.bean.car"};
}else {
return new String[0];
}
}
}
@Import({MyImportSelector.class})
public class SpConfig4 {
}
8、导入实现了ImportBeanDefinitionRegistrar接口的类，通过BeanDefinition注册器注册实名bean,实现对容器中bean的裁定，例如对现有bean的覆盖，进而达成不修改源代码的情况下更换实现的效果文章来源：https://www.toymoban.com/news/detail-739785.html
public class Car {
}
public class Dog {
}
public class MyImportBeanDefinition implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(Dog.class).getBeanDefinition();
//实现对car bean的覆盖，当前car的对象是dog
registry.registerBeanDefinition("car",beanDefinition);
}
}
@Import({MyImportBeanDefinition.class})
public class SpConfig5 {
@Bean
public Car car(){
return new Car();
}
}
9、导入实现了BeanDefinitionRegistryPostProcessor接口的类，通过BeanDefinition的注册器注册实名bean实现对容器中bean的最终定义文章来源地址https://www.toymoban.com/news/detail-739785.html
public class Car {
}
public class Car2 {
private String name;
@Override
public String toString() {
return "Car2{" +
"name='" + name + '\'' +
'}';
}
}
public class MyImportSelector implements ImportSelector {
@Override
public String[] selectImports(AnnotationMetadata importingClassMetadata) {
//各种条件判断
boolean b = importingClassMetadata.hasAnnotation("org.springframework.context.annotation.Import");
System.out.println("flag:"+b);
if (b){
return new String[]{"com.melax.ailatest.bean.car"};
}else {
return new String[0];
}
}
}
@Import({MyPostProcessor.class})
public class SpConfig6 {
@Bean
public Car car(){
return new Car();
}
}
到了这里，关于springBoot bean的多种加载方式的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！
