/**

* 使用javabean和数组存储表格的信息

* 这是常用表格存储方式

* 通过类来规定表结构 通过类的对象代表每一行数据

*/

class Emp{

//employee雇员

private int id;

//属性常用私有private 通过public的get set方法调用

private String name;

private int age;

private boolean man;

private String date;

//通过类的属性规定表格的列 属性名字即表头

public Emp(){}

public Emp(int id, String name, int age, boolean man, String date) {

//alt+insert 生成constructor 构造器

this.id = id;

this.name = name;

this.age = age;

this.man = man;

this.date = date;

}

public int getId() {

//alt+insert 生产 getter and setter

return id;

}

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

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;}

public boolean isMan() { return man; }

public void setMan(boolean man) { this.man = man; }

public String getDate() {return date;}

public void setDate(String date) {this.date = date;}

//只定义了私有属性和公共构造器、setget方法的类 javabean

@Override

public String toString() {

//重写toString

//将返回值类型改为void报错'toString()' in 'Emp' clashes with 'toString()' in 'java.lang.Object'; attempting to use incompatible return type

//方法重写的返回值类型要小于等于父类方法返回值类型

return ("["+getId()+", "+getName()+", "+getAge()+","+(isMan()?"Man":"Woman")+", "+getDate()+"]");

//养成调用属性全用get方法 不直接敲属性 的习惯 日后增删改属性的时候 可以通过改get set方法来让所有调用该属性的程序一起变更

//比如将getAge从int改为String 返回xx+"岁" age本身还是int 仍然可以数学运算 所有调用getAge的表格都更改为了 数字+"岁" 格式 更改类型很方便 也保护了原始数据

}

}

class Form{

public static void main(String[] args) {

Emp emp0 =new Emp(01,"Jack",18,true,"1991-1-1");

//每个对象对应表格的一行 对象每一列内容通过类的属性声明了类型和含义 具体属性的值通过构造器和set方法设定

Emp emp1 = new Emp(02,"Jenny",19,false,"1992-2-2");

Emp emp2 = new Emp(03,"Tom",20,true,"1993-3-3");

Emp[] emps = {emp0,emp1,emp2};

//用一维数组表示表格 每一个元素即对象对应表格的一行

for(int i = 0;i<emps.length;i++){

//遍历数组

if (emps[i].getAge()<19)continue;

//通过get方法调用私有属性age 判断小于19的对象跳过 因为调用属性age是int类型 和数字19比较无需转换类型

System.out.println(

"["+emps[i].getId()+

", "+emps[i].getName()+

", "+emps[i].getAge()+

", "+(emps[i].isMan()?"Man":"Woman")+

", "+emps[i].getDate()+"]");

//太长了换行

}

//通过重写toString来显示遍历信息

for (int i = 0 ; i<emps.length;i++){

if (emps[i].getAge()<19)continue;

System.out.println(emps[i]);

//打印对象时默认打印对象.toString()

//一般打印对象的目的就是打印对象包含的内容 通过更改默认的toString() 让for循环内的语句更直观更易懂

//通过for循环打印数组中每个元素的内容 把每个元素的内容写入toString()方法内 通过打印元素调用默认方法.toString

}

}

}

//练习 创建一个商品表格包含多种信息

class Info{

private int id;

private String name;

private String model;

private double price;

private double discount;

//name商品名 model型号 price价格 discount折扣

public Info(){}

public Info(int id, String name, String model, double price, double discount) {

this.id = id;

this.name = name;

this.model = model;

this.price = price;

this.discount = discount;

}

public int getId() { return id; }

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

public String getName() {return name; }

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

public String getModel() {return model;}

public void setModel(String model) {this.model = model; }

public double getPrice() { return price;}

public void setPrice(double price) {this.price = price; }

public double getDiscount() { return discount; }

public void setDiscount(double discount) {this.discount = discount;}

@Override

public String toString() {

//重写toString返回对象的所有信息

return "["+getId()+", "+getName()+", "+getModel()+", "+getPrice()+", "+getDiscount()+"]";

}

public String up(double p){

if (p<getPrice()*getDiscount()) {

//输入一个值，筛选出折后价大于该值的商品

return this+"\n";

//this即 this.toString()

}

return "";

}

}

class Form1{

public static void main(String[] args) {

Info in0 = new Info(1,"mouse","BZ",99.21,0.9);

Info in1 = new Info(2,"keyboard","WO",403.00,0.7);

Info in2 = new Info(3,"book","BK",89.00,0.8);

Info in3 = new Info(4,"cloth","GQ",700.00,0.5);

Info in4 = new Info(5,"phone","DM",900.00,0.3);

Info[] f = {in0,in1,in2,in3,in4};

for (int i = 0;i<f.length;i++){

//f.length 数组f的长度

System.out.println(f[i]);

}

Scanner s = new Scanner(System.in);

System.out.println("请输入价格，回车后显示折后价高于该价格的商品");

double s1 = s.nextDouble();

for (int i = 0;i<f.length;i++){

System.out.print(f[i].up(s1));

}

}

}