Java 封装的使用详解

package com.xdr630.encap;

public class Encapsulation01 {

    public static void main(String[] args) {

        Person person = new Person();
        person.setName("兮动人");
        person.setAge(1000);
        person.setSalary(30000);
        System.out.println(person.info());
        System.out.println(person.getSalary());

    }
}

class Person {
    public  String name; //名字公开
    private int age; //age 私有化
    private double salary; //..


    public String getName() {
        return name;
    }
    public void setName(String name) {
        //加入对数据的校验,相当于增加了业务逻辑
        if(name.length() >= 2 && name.length() <=6 ) {
            this.name = name;
        }else {
            System.out.println("名字的长度不对，需要(2-6)个字符，默认名字");
            this.name = "无名人";
        }
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        //判断
        if(age >= 1 && age <= 120) {//如果是合理范围
            this.age = age;
        } else {
            System.out.println("你设置年龄不对，需要在 (1-120), 给默认年龄18 ");
            this.age = 18;//给一个默认年龄
        }
    }

    public double getSalary() {
        //可以这里增加对当前对象的权限判断
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }
    //写一个方法，返回属性信息
    public String info() {
        return "信息为 name=" + name  + " age=" + age + " 薪水=" + salary;
    }
}

		//如果我们自己使用构造器指定属性
        Person person1 = new Person("云兮动人", 200, 10000);
        System.out.println("====兮动人的信息====");
        System.out.println(person1.info());

	//有三个属性的构造器
    public Person(String name, int age, double salary) {
       /* this.name = name;
        this.age = age;
        this.salary = salary;*/
        //可以将 set 方法写在构造器当中，这样仍然可以验证
        setName(name);
        setAge(age);
        setSalary(salary);
    }

public class Account {
    //为了封装，将3个属性设置为private
    private String name;
    private double balance;
    private String pwd;

    //提供两个构造器
    public Account() {
    }

    public Account(String name, double balance, String pwd) {
        this.setName(name);
        this.setBalance(balance);
        this.setPwd(pwd);
    }

    public String getName() {
        return name;
    }

    //姓名（长度为2位3位或4位）
    public void setName(String name) {
        if (name.length() >= 2 && name.length() <= 4) {
            this.name = name;
        } else {
            System.out.println("姓名要求（长度为2位3位或4位），默认值 无名");
            this.name = "无名";
        }
    }

    public double getBalance() {
        return balance;
    }

    //余额(必须>20)
    public void setBalance(double balance) {
        if (balance > 20) {
            this.balance = balance;
        } else {
            System.out.println("余额(必须>20) 默认为0");
        }
    }

    public String getPwd() {
        return pwd;
    }

    //密码（必须是六位）
    public void setPwd(String pwd) {
        if (pwd.length() == 6) {
            this.pwd = pwd;
        } else {
            System.out.println("密码（必须是六位）默认密码为 000000");
            this.pwd = "000000";
        }
    }
    //显示账号信息
    public void showInfo() {
        //可以增加权限的校验
        System.out.println("账号信息 name=" + name + " 余额=" + balance + " 密码" + pwd);
//        if() {
//            System.out.println("账号信息 name=" + name + " 余额=" + balance + " 密码");
//        }else{
//            System.out.println("你无权查看...");
//        }
    }
}

public class TestAccount {
    public static void main(String[] args) {
        //创建Account
        Account account = new Account();
        account.setName("jack");
        account.setBalance(60);
        account.setPwd("123456");

        account.showInfo();
    }
}