Spring简单使用（依赖注入）

spring

IOC&＃xff08;Inversion of Control&＃xff09;:控制反转

创建对象的方式改变了&＃xff0c;以前是new创建对象&＃xff0c;现在时通过Spring创建对象


AOP&＃xff08;Aspect Oriented Programming&＃xff09;:面向切片编程

创建代码会有很多重复的部分&＃xff0c;如异常处理、日志等。只需要写一遍&＃xff0c;利用aop写入程序中


spring核心包

beans&＃xff1a;bean管理
Context&＃xff1a;上下文&＃xff08;体现在xml配置&＃xff09;
Expression Language&＃xff1a;spring EL表达式
Core&＃xff1a;spring框架核心

spring入门程序

UserDao.java

package cn.edu.usts.spring;public class UserDao {
public void say() {System.out.println("spring test&＃xff01;&＃xff01;");
}
}

applicationContext.xml

spring-framework-4.3.6.RELEASE-dist\spring-framework-4.3.6.RELEASE\docs\spring-framework-reference\html\index.html------>7.2.1



<beans xmlns&＃61;"http://www.springframework.org/schema/beans"xmlns:xsi&＃61;"http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation&＃61;"http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-4.3.xsd"><bean id&＃61;"userDao" class&＃61;"cn.edu.usts.spring.UserDao">bean>beans>

Test,java

package cn.edu.usts.spring;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;import cn.edu.usts.spring.UserDao;public class Test {public static void main(String[] args) {// 实例化容器ApplicationContext applicationContext &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");// 通过容器获取实例UserDao userDao &＃61; (UserDao)applicationContext.getBean("userDao");// 使用实例中方法userDao.say();}}

通过set方法进行依赖注入

UserService.java

package cn.edu.usts.spring;public class UserService {public UserDao userDao;public void setUserDao(UserDao userDao) {this.userDao &＃61; userDao;}public void say(){System.out.println("userService say test!!!");this.userDao.say();}
}

applicationContext.xml

package cn.edu.usts.spring;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test {public static void main(String[] args) {ApplicationContext applicationContext &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");UserService userService &＃61; (UserService)applicationContext.getBean("userService");userService.say();}}

Test.java

package cn.edu.usts.spring;import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Test {public static void main(String[] args) {ApplicationContext applicationContext &＃61; new ClassPathXmlApplicationContext("applicationContext.xml");UserService userService &＃61; (UserService)applicationContext.getBean("userService");userService.say();}}