1） 使用無參構造方法實例化

它會根據默認無參構造方法來創建類對象，如果bean中沒有默認無參構造函數，將會創建失敗

<?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="impl" class="com.Impl"></bean>
</beans>

2） 工廠靜態方法實例化

工廠的靜態方法返回Bean實例

<?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="impl" class="com.StaticFactoryBean" factory-method="create"></bean>
</beans>

public class StaticFactoryBean {public  static ImplDao create(){return new ImplDao();}
}

3） 工廠實例方法實例化

工廠的非靜態方法返回Bean實例

public class DynamicFactoryBean {public   ImplDao create(){return new ImplDao();}
}

<?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="factoryBean" class="com.DynamicFactoryBean"/><bean id="impl" factory-bean="factoryBean" factory-method="create"/>
</beans>