spring01通过xml配置文件实例化bean对象

方法-：xml

1.添加依赖

   <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.12.RELEASE</version>
      <scope>compile</scope>
    </dependency>

2.创建一个对象包含一个方法

1 public class UserService {
2     public  void test() {
3         System.out.println("userservice is satrt ............");
4     }
5 }

3.在resource 包下新建spring.xml配置文件

<?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">

<!--    id 对象名称首字母小写 class 包名-->
    <bean id="userService" class="org.example.serivce.UserService"></bean>

</beans>

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4.新建java文件并运行

public class test01 {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
        UserService userService = (UserService) context.getBean("userService");
        userService.test();

    }
}

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5.运行结果

方法二：

通过@Configuration注解

1.在对象上加上类注解，方法上添加@Bean注解

@Configuration
public class UserService {
    @Bean
    public  void test() {
        System.out.println("userservice is satrt ............");
    }
}

2.调用

public class test01 {
    public static void main(String[] args) {
        ApplicationContext context = new AnnotationConfigApplicationContext(UserService.class);//注意这里与xml不同
        UserService userService = (UserService) context.getBean("userService");
        userService.test();
    }
}