聊一聊Spring常用的三种依赖注入（无参构造注入，有参构造注入，set方法注入）。

迈不过友情╰ 2022-11-10 14:21 275阅读 0赞

### Spring依赖注入 ###

*  环境配置
 *  无参构造注入
 *  有参构造方法注入
 *  结果展示
 *  set方法注入

# 环境配置 #

java8，idea，spring5的jar包

# 无参构造注入 #

1.首先编写一个无参构造的类。

public class User {
        
    
        public void add(){
        
            System.out.println("add方法执行.......");
        }
    }

2.xml文件配置  
![在这里插入图片描述][20210318201155878.png]

<bean id="user" class="com.jaoyang.spring_ioc_01.User"></bean>

3.方法测试

@Test
        public void testAdd(){
        
            //1.加载spring配置文件
            ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
            //2.获取配置文件创建的对象
            User user = context.getBean("user", User.class);
            System.out.println(user);
            user.add();
    
        }

4.测试结果![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ3Njk5MDc2_size_16_color_FFFFFF_t_70]

# 有参构造方法注入 #

1.创建一个有参构造类

public class Orders {
        
    
        private String name;
        private String address;
    
        public Orders(String name, String address) {
        
            this.name = name;
            this.address = address;
        }
    
        public void print_orders_data(){
        
            System.out.println("商品:" +  name + "------>>" + "地址:" + address);
        }
    
    }

2.配置xml文件  
![在这里插入图片描述][20210318201837804.png]

<bean id="orders" class="com.jaoyang.spring_ioc_01.Orders">
            
            <constructor-arg name="name" value="苹果"></constructor-arg>
            <constructor-arg name="address" value="洛杉矶"></constructor-arg>
        </bean>

3.代码测试

@Test
        public void testorders(){
        
            //1.加载spring配置文件
            ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
            //2.获取配置文件创建的对象
            Orders orders = context.getBean("orders", Orders.class);
            System.out.println(orders);
            orders.print_orders_data();
    
        }

# 结果展示 #

![在这里插入图片描述][20210318202136151.png]

# set方法注入 #

1.创建一个带set方法的类

public class Book {
        
        private String bookname;
        private String bookauthor;
    
        public void setBookname(String bookname) {
        
            this.bookname = bookname;
        }
    
        public void setBookauthor(String bookauthor) {
        
            this.bookauthor = bookauthor;
        }
    
        public void print_book_data(){
        
            System.out.println("作者:" + bookauthor + "----->" + "书名:" + bookname);
        }
    }

2.配置xml文件  
![在这里插入图片描述][20210318202335413.png]

<bean id="book" class="com.jaoyang.spring_ioc_01.Book">
            
            <property name="bookauthor" value="余华"></property>
            <property name="bookname" value="《在细雨中的呐喊》"></property>
        </bean>

3.代码测试

@Test
        public void testbook(){
        
            //1.加载spring配置文件
            ApplicationContext context = new ClassPathXmlApplicationContext("bean1.xml");
            //2.获取配置文件创建的对象
            Book book = context.getBean("book", Book.class);
            System.out.println(book);
            book.print_book_data();
    
        }

4.结果测试  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ3Njk5MDc2_size_16_color_FFFFFF_t_70 1]

[20210318201155878.png]: /images/20221022/7cb3d4c9ca714dcdab29a0ea7176e70c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ3Njk5MDc2_size_16_color_FFFFFF_t_70]: /images/20221022/d36efc89c43f4c5ba54ffb7ca85d3dd0.png
[20210318201837804.png]: https://img-blog.csdnimg.cn/20210318201837804.png
[20210318202136151.png]: https://img-blog.csdnimg.cn/20210318202136151.png
[20210318202335413.png]: https://img-blog.csdnimg.cn/20210318202335413.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ3Njk5MDc2_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20210318203111459.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ3Njk5MDc2,size_16,color_FFFFFF,t_70