小白入门spring——IOC依赖注入

向右看齐 2022-12-12 15:23 133阅读 0赞

(1）什么是依赖注入  
Dl(dependency injection)依赖注入  
含义:就是给对象的属性设置值.  
原来给对象的属性设置值: set方法给对象设置值和构造方法给对象初始化的时候设置值.  
(2) property标签  
set方式设置属性(掌握)  
让spring调set方法，前提条件类中必须有set方法

思维导图:

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center]

## 第一种赋值方式:set方法 ##

接着上一篇的代码,再添加property

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 1]

`<property name="id" value="10"></property>`

## applicationContext.xml ##

测试效果:

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 2]

## 第二种赋值方式:构造器 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 3]

`<constructor-arg name="id" value="10"></constructor-arg>`

## applicationContext.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="person" class="com.lbl.domain.Person">
            <constructor-arg name="id" value="10"></constructor-arg>
            <constructor-arg name="age" value="20"></constructor-arg>
            <constructor-arg name="name" value="李柏霖"></constructor-arg>
        </bean>
    </beans>

运行效果:

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 4]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/2eda6be3b80d41a6bc8a8ab3fc6a5bc4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221123/5d30c2944163498d989dde72f83e96d4.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 2]: /images/20221123/09742de621de4387a7943df43ce5408f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 3]: /images/20221123/5dbb7499659b4c74a5e2dcb5a3366dd5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3OTI0OTA1_size_16_color_FFFFFF_t_70_pic_center 4]: /images/20221123/6c0ebe58053045c9a41de3b8dc062a93.png