Spring的IoC入門案例

一、建立工程，導入座標

1.1 建立工程

1.2 導入座標

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>spring_01_ioc_xml</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.0.2.RELEASE</version>
        </dependency>
    </dependencies>

</project>

二、建立三層對象

2.1 controller

public class UserController {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = ac.getBean("userService", UserService.class);
        userService.saveUser();
    }
}

2.2 service

1）UserService

public interface UserService {
    /**
     * 模擬保存用戶
     */
    void saveUser();
}

2）UserServiceImpl

public class UserServiceImpl implements UserService {
    private UserDao userDao;

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public void saveUser() {
        userDao.saveUser();
    }
}

2.3 dao

1）UserDao

public interface UserDao {
    /**
     * 模擬保存用戶
     */
    void saveUser();
}

2）UserDaoImpl

public class UserDaoImpl implements UserDao {
    public void saveUser() {
        System.out.printf("用戶保存成功！");
    }
}

三、Spring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">

    <bean id="userDao" class="com.itcast.dao.impl.UserDaoImpl"></bean>

    <bean id="userService" class="com.itcast.service.impl.UserServiceImpl">
        <property name="userDao" ref="userDao"></property>
    </bean>

</beans>

四、測試結果

用戶保存成功！
Process finished with exit code 0