Spring 入门

	```xml
	<dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-context</artifactId>
	    <version>5.0.5.RELEASE</version>
	</dependency>
	```

	```java
	package com.ruochen.dao;

public interface UserDao {

    public void save();

}

```

- 实现类：`UserDaoImpl.java`
```java
package com.ruochen.dao.impl;

import com.ruochen.dao.UserDao;

public class UserDaoImpl implements UserDao {

    @Override

    public void save() {

        System.out.println("save running...");

    }

}

```

	```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="userDao" class="com.ruochen.dao.impl.UserDaoImpl"></bean>

</beans>

```

	```java
	package com.ruochen.demo;

import com.ruochen.dao.UserDao;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserDaoDemo {

    public static void main(String[] args) {

        ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");

        UserDao userDao = (UserDao) app.getBean("userDao");

        userDao.save();

    }

}

```

	save running...