ioc入门案例

 1、pom.xml引入spring

    <dependencies>
        <!-- 引入spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

2、写一个业务层接口和它的实现类

public interface UserService {
    public void save();
}

public class UserServiceImpl implements UserService {
    @Override
    public void save() {
        System.out.println("runing...");
    }
}

3、在resources中编写spring配置文件applicationContext.xml，在xml中配置控制的资源，也就是刚刚编写的实现类

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">
    <!-- 配置spring控制的资源 -->
    <bean id="userService" class="com.hw.service.impl.UserServiceImpl"/>
</beans>

4、测试：加载配置文件、获取资源

public class UserServiceTest
{
    @Test
    public void shouldAnswerWithTrue()
    {
        //加载springcontext的配置文件
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        //获取资源
        UserService userService = (UserService) ctx.getBean("userService");
        userService.save();
    }
}