TengFei’s Blog - Spring简单使用（依赖注入）

spring

IOC（Inversion of Control）:控制反转

 创建对象的方式改变了，以前是new创建对象，现在时通过Spring创建对象

AOP（Aspect Oriented Programming）:面向切片编程

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

spring核心包

beans：bean管理 Context：上下文（体现在xml配置） Expression Language：spring EL表达式 Core：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！！");
}
}

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

<?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-4.3.xsd">

    <bean id="userDao" class="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 = new ClassPathXmlApplicationContext("applicationContext.xml");
        // 通过容器获取实例
        UserDao userDao = (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 = 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 = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = (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 = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService userService = (UserService)applicationContext.getBean("userService");
        userService.say();
    }
    
}