面向对象思想:
A:属性 ---- 就是事物的描述信息 B:行为 ---- 事物能够做什么 类:一组相关属性和行为的集合 对象:就是该事物的具体体现
package myTest;
/**
* Created by JackFeng on 2020/3/2.
*/
public class Phone {
String barnd;
int price;
String color;
public void call(String name) {
System.out.println("给" + name + "打电话");
}
public void sendMessage(){
System.out.println("给所有人群发短信");
}
}
package myTest;
/**
* Created by JackFeng on 2020/3/2.
*/
public class PhoneDemo {
public static void main(String[] args) {
Phone p = new Phone();
System.out.println(p.barnd + "---" +p.price+ "----"+p.color);
p.barnd = "iphone";
p.price = 8888;
p.color = "金色";
System.out.println(p.barnd + "---" +p.price+ "----"+p.color);
p.call("DataScience");
p.sendMessage();
}
}
区别:
package myTest;
/**
* Created by JackFeng on 2020/3/2.
*/
public class Variable {
// 成员变量
int x;
public void show (){
//局部变量
// int y; // 如果y 没有值 就会报错
int y = 1; // 赋值就会不报错
System.out.println(y);
// 调用x 有默认值
System.out.println(x);
}
}
package myTest;
/**
* Created by JackFeng on 2020/3/2.
*/
public class StudentDemo {
public static void main(String[] args) {
// 无参 + set方法
Student s = new Student();
s.setName("Data");
s.setAge(26);
System.out.println(s.getName()+"===="+s.getAge());
// 带参构造
Student s2 = new Student("DataScinece", 26);
System.out.println(s2.getName()+"===="+s2.getAge());
}
}
package myTest;
/**
* Created by JackFeng on 2020/3/2.
*/
public class Student {
private String name;
private int age;
// 构造方法
// 无参数
public Student(){}
// 有参数
public Student(String name, int age ){
this.name = name;
this.age = age;
}
// get set 方法
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
如果类名作为形式参数传递
如果类名作为返回值类型
(本章主要实验封装)