Spring实践（一）

spring实践（一）

1 创建项目结构
2 Hello类

package younghd;

public class Hello {
    private String name;
    private  String id;

    public String getName() {
        return name;
    }

    public Hello() {
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public Hello(String id,String name) {
        this.name = name;
        this.id = id;
    }
}

3 XML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 = "chinese" class="younghd.Hello">
        <property name="id" value="中文"/>
        <property name="name" value="你好"/>
    </bean>
    <bean id = "english" class="younghd.Hello">
        <property name = "id" value="英语"/>
        <property name = "name" value="hello"/>
    </bean>
    <bean id="korea" class="younghd.Hello">
         <constructor-arg value="韩国"></constructor-arg>
        <constructor-arg value="撒狼嘿呦"></constructor-arg>
    </bean>
</beans>

4 测试类

package younghd;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestIoc {
    public static void main(String[] args){
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        System.out.println("强制转换： ");
        Hello hello1 = (Hello)ac.getBean("chinese");
        System.out.println(hello1.getId()+":"+hello1.getName());
        System.out.println("类的反射： ");
        Hello hello2 = ac.getBean("english",Hello.class);
        System.out.println(hello2.getId()+":"+hello2.getName());
        System.out.println("构造函数");
        Hello hello3 = ac.getBean("korea",Hello.class);
        System.out.println(hello3.getId()+":"+hello3.getName());
    }
}

5 结果展示

6 体会
1.普通的java程序创建对象，是通过new方法实现，对象需要我们自己管理
2. Spring的java程序，对象是由Spring管理，当我们需要某个对象时，就通过Spring容器获取对象的实例
3. Spring的id可以认为是bean的标识符，是唯一的