封装

封装要点:属性私有,get/set

封装的意义:

1. 提高程序的安全性,保护数据
2. 隐藏代码的实现细节
3. 统一接口
4. 提高系统的可维护性

package oop.seal;

public class Student {
    //属性私有
    private String name;
    private int id;
    private char sex;
    private int age;

    //提供可以操作属性的方法
    public String getName(){
        return this.name;
    }
    public void setName(String name){
        this.name = name;
    }

    public int getId() {
        return id;
    }

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

    public char getSex() {
        return sex;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        //设置年龄范围
        if(age>120 || age<0){
            System.out.println("error");
        }else {this.age = age;}
    }
}

package oop.seal;

import java.util.Scanner;

public class Application {
    public static void main(String[] args) {

        Student s1 = new Student();
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入年龄");
        int input = scanner.nextInt();
        s1.setName("qinjiang");
        System.out.println(s1.getName());
        s1.setAge(input);
        System.out.println(s1.getAge());
    }
}