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最新推荐文章于 2025-04-28 15:30:00 发布

原创最新推荐文章于 2025-04-28 15:30:00 发布 · 135 阅读

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本文探讨了Java中创建对象的不同方式，重点讲解了Spring框架下对象注入，同时涉及如何在不修改代码的情况下通过配置文件切换USB设备。

代码
Text:

public static void fct(Usbinterface a,String b){
        a.read();
        a.write(b);

    }
/*
*
* Java中创建对象的方式有几种啊？
*
* 1.new ：地球人都知道。
* 2.clone
* 3.反射
* 4.对象反序列化
* -----------------------------------------------
*
* 1.如何创建对象？
*   地球人都知道，使用new。
*
* Spring也不使用new来创建对象，使用ioc容器来注入的。
*
* */
    public static void main(String[] args) throws Exception {
        /*Student student = new Student(1, "宋小宝", "男", "199502", "插秧");
        System.out.println(student);
        student.getClass().getConstructor().newInstance(1, "宋小宝", "男", "199502", "插秧");

        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        Student s = (Student) context.getBean("s");*/

        /*Student student = new Student(1, "宋小宝", "男", "199502", "插秧");
        Class<? extends Student> aClass = student.getClass();
        Student student1 = aClass.getConstructor().newInstance();
        student1.setId(2);
        student1.setBrithday("19950224");
        student1.setMajor("zhuanye");
        student1.setName("张三");
        System.out.println(student1);*/


        /*Usbdisk usbdisk = new Usbdisk();
        usbdisk.read();
        usbdisk.write("zhengza");*/


//使用了spring ioc 容器注入了一个对象。没有使用new.内部也是通过反射+xml文档的解析来实现的。
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

        Object disk = context.getBean("disk");

        fct((Usbinterface) disk,"nihai");

//有没有办法，不允许修改代码的前提下，把u盘换成移动硬盘。有办法吗？
        //正所谓鱼与熊掌不可兼得，你虽然没有修改代码，但是你还是修改了配置文档，哪个配置文档,applicationContext.xml
        //一点不改是不可能的。


    }

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 http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="s" class="com.gg.domain.Student">
        <property name="id" value="1"></property>
        <property name="name" value="郭建"></property>
        <property name="sex" value="男"></property>
        <property name="brithday" value="199502"></property>
        <property name="major" value="大招"></property>

    </bean>

    <bean id="disk" class="com.gg.dao.impl.Usbdisk">


    </bean>
</beans>

usbinterface:

public interface Usbinterface {
    public void read();
    public void write(String a);
}

usbDisk:

public class Usbdisk implements Usbinterface {
    @Override
    public void read() {

        System.out.println("移动硬盘读取数据中....");
    }

    @Override
    public void write(String a) {

        System.out.println("移动硬盘写入数据：" + a);
    }
}

MoveDisk:

public class MoveDisk implements Usbinterface {
    @Override
    public void read() {

        System.out.println("U盘读取数据中...");
    }

    @Override
    public void write(String a) {

        System.out.println("U盘写入数据：" + a);
    }
}

Student:

public class Student {
    private int id;
    private String name;
    private String sex;
    private String brithday;
    private String major;

    public Student(int id, String name, String sex, String brithday, String major) {
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.brithday = brithday;
        this.major = major;
    }
    public Student(){}

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

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

    public void setSex(String sex) {
        this.sex = sex;
    }

    public void setBrithday(String brithday) {
        this.brithday = brithday;
    }

    public void setMajor(String major) {
        this.major = major;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getSex() {
        return sex;
    }

    public String getBrithday() {
        return brithday;
    }

    public String getMajor() {
        return major;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", brithday='" + brithday + '\'' +
                ", major='" + major + '\'' +
                '}';
    }
}