04_封装

1. 程序追求高内聚，低耦合
2. 属性私有，get/set

public class Student {

    private String name;
    private int age;
    private char gender;

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        if(age<0 || age>120){
            this.age=3;
        }else{
            this.age = age;
        }
    }

    public char getGender() {
        return gender;
    }

    public void setGender(char gender) {
        this.gender = gender;
    }
}

public class Application {
    public static void main(String[] args) {
        Student s1 = new Student();
        s1.setAge(100);
        System.out.println(s1.getAge());
    }
}