spring入门案例
案例环境说明
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模拟三层架构中表现层调用业务层功能
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表现层:UserApp模拟UserServlet(使用main方法模拟)
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IoC入门案例制作步骤
1.导入spring坐标(5.1.9.release)
2.编写业务层与表现层(模拟)接口与实现类
3.建立spring配置文件
4.配置所需资源(Service)为spring控制的资源
导入spring坐标:
<dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>5.1.9.RELEASE</version> </dependency>
编写表现层、业务层接口和实现类:
业务层接口:
public interface UserService { //业务方法 void save(); }
业务层实现类:
public class UserServiceImpl implements UserService { public void save() { System.out.println("user service running..."); } }
创建spring配置文件applicationContext.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 https://www.springframework.org/schema/beans/spring-beans.xsd"> <!-- 1.创建spring控制的资源--> <bean id="userService" class="com.itheima.service.impl.UserServiceImpl"/> </beans>
模拟表现层加载获取spring资源:
public class UserApp { public static void main(String[] args) { //2.加载配置文件 ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); //3.获取资源 UserService userService = (UserService) ctx.getBean("userService"); userService.save(); } }