三种getBean的方法

三种getBean的方法 （重载 参数不同）

public interface BeanFactory {
String FACTORY_BEAN_PREFIX = "&";

Object getBean(String var1) throws BeansException;

T getBean(String var1, Class var2) throws BeansException;

Object getBean(String var1, Object... var2) throws BeansException;

T getBean(Class var1) throws BeansException;

T getBean(Class var1, Object... var2) throws BeansException;

ObjectProvider getBeanProvider(Class var1);

ObjectProvider getBeanProvider(ResolvableType var1);

区别

1.根据id，xml配置文件可以有多个相同类型的bean 返回Object对象 2.根据类型，xml配置文件中不能有相同class的bean，返回bean对象

配置了多个同类型bean，此时使用类型的方法获得，会报错如下；

UserServiceImpl bean = applicationContext.getBean(UserServiceImpl.class);

No qualifying bean of type 'com.z.service.Impl.UserServiceImpl' available: expected single matching bean but found 2: Service2,Service

3.根据id和类型

UserServiceImpl bean = applicationContext.getBean("Service2",UserServiceImpl.class);

返回bean对象