Spring (4) annotation injection

Annotation injection creates objects

Spring annotation injection is a more common way

1. Component (basically the same as the use of the following three)
2. Controller (presentation layer)
3. Service (business layer)
4. Repository (persistence layer)

Before using annotations, you need to modify the configuration information of the original bean.xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
	http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context-3.0.xsd">


<!--  注解形式  -->
    <context:component-scan base-package="imis"></context:component-scan>
</beans>

First introduce the first annotation Component

/**Component
    作用：用于把当前类对象存入spring容器中
    属性：
        value：用于指定bean的id，当不写时，默认为当前的类名，首字母改为小写
 */

@Component
public class UserServiceImpl implements IUserService {
    
    
    private String name;
    private Integer age;
    private Date birthday;

    public UserServiceImpl() {
    
    
    }

    public UserServiceImpl(String name, Integer age, Date birthday) {
    
    
        this.name = name;
        this.age = age;
        this.birthday = birthday;
    }

    public void queryAll() {
    
    
        System.out.println(name+","+age+","+birthday+".");
    }
}