XMU Java第四次实验

Java第四次实验

正八边形类

描述

写一个正八边形类Octagon，要求从课本的GeometricObject类继承，并实现 Comparable和 Cloneable接口。
写一个测试类，测试Octagon类的所有可用方法。

设计思路

实现Octagon类，从GeometricObject类中继承，并覆盖Clone和Compareto方法。在主类中测试clone和comparato方法。

代码

GeometricObject类

package com.company;
import java.util.Date;
public abstract class GeometricObject {
    private String color = "white";
    private boolean filled = false;
    private Date dateCreated;

    protected GeometricObject()
    {
        this.dateCreated = new Date();
    }

    protected GeometricObject(String color, boolean filled)
    {
        this.dateCreated = new Date();
        this.color = color;
        this.filled = filled;
    }

    public String getColor()
    {
        return this.color;
    }

    public void setColor(String color)
    {
        this.color = color;
    }

    public boolean isFilled()
    {
        return this.filled;
    }

    public void setFilled(boolean filled)
    {
        this.filled = filled;
    }

    public Date getDateCreated()
    {
        return this.dateCreated;
    }
    @Override
    public String toString()
    {
        return "created on " + dateCreated + "\ncolor: " + color +
                " and filled: " + filled;
    }
    public abstract double getArea();
    public abstract double getPerimeter();
}

Octagon类

package com.company;

public class Octagon extends GeometricObject implements Cloneable,Comparable<Octagon>{
    double side;
    public Octagon(double side)
    {
        this.side = side;
    }
    public Octagon(double side, String color, boolean filled)
    {
        this.side = side;
        setColor(color);
        setFilled(filled);
    }

    public double getSide() {
        return side;
    }

    public void setSide(double side) {
        this.side = side;
    }

    @Override
    public double getArea() {
        return (2 + 4 / Math.sqrt(2)) * side * side;
    }

    @Override
    public double getPerimeter() {
        return 8 * side;
    }

    @Override
    public Object clone() throws CloneNotSupportedException
    {
        return super.clone();
    }

    @Override
    public int compareTo(Octagon o)
    {
        if(this.side > o.side)
            return 1;
        else if(this.side < o.side)
            return -1;
        else
            return 0;
    }
}

测试类

package com.company;

public class Main {

    public static void main(String[] args) {

        Octagon o = new Octagon(3);

        System.out.println("Area: " + o.getArea());
        System.out.println("o's Perimeter: " + o.getPerimeter());

        Octagon o1 = new Octagon(2);
        try
        {
            o1 = (Octagon)o.clone();
            System.out.println("o1's Perimiter : "+o1.getPerimeter());
        }
        catch(CloneNotSupportedException ex)
        {
            System.out.println("CloneNotSupportedException");
        }

        System.out.println(o.compareTo(o1));

    }
}

效果

MyRational

描述

改写课本Listing 13.13的分数类Rational，将分子和分母从类型long改为BigInteger，新版分数类名为MyRational。
写一个测试类，测试MyRational。

设计思路

源代码中的long类型数据全部换成BigInteger，使用BigInteger的静态方法进行四则运算,按照错误提示按部就班修改代码，熟悉了BigInterger的使用方法，加深了对继承和接口的理解。

代码

MyRational类

package com.company;
import java.math.BigInteger;
public class MyRational extends Number implements Comparable {
    private BigInteger numerator=new BigInteger("0");
    private BigInteger denominator=new BigInteger("1");
    public MyRational()
    {
        this(new BigInteger("0"), new BigInteger("1"));
    }
    public MyRational(BigInteger numerator, BigInteger denominator)
    {
        BigInteger gcd=gcd(numerator,denominator);
        this.numerator = ((new BigInteger(denominator.compareTo(BigInteger.ZERO) + "")).multiply(numerator)).divide(gcd);
        this.denominator = denominator.abs().divide(gcd);
    }

    private static BigInteger gcd(BigInteger n, BigInteger d)
    {
        BigInteger n1=n.abs();
        BigInteger n2=d.abs();
        BigInteger gcd=new BigInteger("1");
        for(BigInteger k = BigInteger.ONE; k.compareTo(n1) <= 0 && k.compareTo(n2) <= 0; k = k.add(BigInteger.ONE))
        {
            if(n1.mod(k).compareTo(BigInteger.ZERO) == 0 && n2.mod(k).compareTo(BigInteger.ZERO) == 0)
                gcd = k;
        }
        return gcd;
    }
    public BigInteger getNumerator()
    {
        return numerator;
    }
    public BigInteger getDenominator()
    {
        return denominator;
    }
    public MyRational add(MyRational secondMyRational)
    {
        BigInteger n = numerator.multiply(secondMyRational.getDenominator()).add(
                denominator.multiply(secondMyRational.getNumerator()));
        BigInteger d = denominator.multiply(secondMyRational.getDenominator());
        return new MyRational(n, d);
    }
    public MyRational subtract(MyRational secondMyRational)
    {
        BigInteger n = numerator.multiply(secondMyRational.getDenominator()).subtract(
                denominator.multiply(secondMyRational.getNumerator()));
        BigInteger d = denominator.multiply(secondMyRational.getDenominator());
        return new MyRational(n, d);
    }
    public MyRational multiply(MyRational secondMyRational)
    {
        BigInteger n = numerator.multiply(secondMyRational.getNumerator());
        BigInteger d = denominator.multiply(secondMyRational.getDenominator());
        return new MyRational(n, d);
    }
    public MyRational divide(MyRational secondMyRational)
    {
        BigInteger n = numerator.multiply(secondMyRational.getDenominator());
        BigInteger d = denominator.multiply(secondMyRational.getNumerator());
        return new MyRational(n, d);
    }
    public String toString()
    {
        if(denominator.compareTo(BigInteger.ONE) == 0)
        {
            return numerator+"";
        }else
            return numerator+"/"+denominator;
    }
    public boolean equals(Object parm1)
    {
        if((this.subtract((MyRational)parm1)).getNumerator().equals(0))
            return true;
        else
            return false;
    }
    @Override
    public int compareTo(Object o) {
        // TODO Auto-generated method stub
        if((this.subtract((MyRational)o)).getNumerator().compareTo(BigInteger.ZERO) == 1)
            return 1;
        else if((this.subtract((MyRational)o)).getNumerator().compareTo(BigInteger.ZERO) == -1)
            return -1;
        else
            return 0;
    }

    @Override
    public int intValue() {
        // TODO Auto-generated method stub
        return (int)doubleValue();
    }

    @Override
    public long longValue() {
        // TODO Auto-generated method stub
        return (long)doubleValue();
    }

    @Override
    public float floatValue() {
        // TODO Auto-generated method stub
        return (float)doubleValue();
    }

    @Override
    public double doubleValue() {
        // TODO Auto-generated method stub
        return numerator.doubleValue() * 1.0 / denominator.doubleValue();
    }

}

Test类

package com.company;

import com.sun.jmx.snmp.SnmpTooBigException;

import java.math.BigInteger;

public class Main {

    public static void main(String[] args) {
	// write your code here
        MyRational r1=new MyRational(new BigInteger("4"),new BigInteger("2"));
        MyRational r2=new MyRational(new BigInteger("2"),new BigInteger("3"));
        System.out.println(r1+"+"+r2+"="+r1.add(r2));
        System.out.println(r1+"-"+r2+"="+r1.subtract(r2));
        System.out.println(r1+"*"+r2+"="+r1.multiply(r2));
        System.out.println(r1+"/"+r2+"="+r1.divide(r2));
        System.out.println(r2+" is "+r2.doubleValue());
    }
}

效果

发扑克牌

描述

编程实现程序每次启动后，在界面上随机显示54张扑克牌中的4张，并在其下方显示花色名（如图）。扑克牌图片已打包到cards.jar文件中，命名规则见下一页。

扑克牌命名规则

友情赠送：从jar中读取指定图片的方法

import java.util.jar.;
import java.io.;
import javafx.scene.image.*;
public static ImageView readImageFromJar(String jarname, String picname) {
ImageView imageView = null;
try {
JarFile jarFile = new JarFile(jarname);
JarEntry entry = jarFile.getJarEntry(picname);
InputStream in = jarFile.getInputStream(entry);
imageView = new ImageView(new Image(in));
in.close();
jarFile.close();
} catch (IOException e) {
System.err.println(“read file error.”);
}
return imageView;
}
读方块3图片的使用示例：
ImageView imageView = readImageFromJar(“cards.jar”,“cards/29.png”);

设计思路

生成四个随机数，读取jar里面的图片内容，使用getName方法获取扑克牌的名字。采用GridPane放置扑克牌。

代码

//package Conv.company;
//
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;
import javafx.geometry.Insets;

import java.util.HashMap;
import java.util.jar.*;
import java.io.*;
import javafx.scene.image.*;
import javafx.scene.text.Text;

public class Card extends Application {
    public static ImageView readImageFromJar(String jarname, String picname) {
        ImageView imageView = null;
        try {
            JarFile jarFile = new JarFile(jarname);
            JarEntry entry = jarFile.getJarEntry(picname);
            InputStream in = jarFile.getInputStream(entry);
            imageView = new ImageView(new Image(in));
            in.close();
            jarFile.close();
        } catch (IOException e) {
            System.err.println("read file error.");
        }
        return imageView;
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        GridPane pane = new GridPane();
        pane.setPadding(new Insets(5,5,5,5));
        int r1=(int)((Math.random()*100)%54);
        int r2=(int)((Math.random()*100)%54);
        int r3=(int)((Math.random()*100)%54);
        int r4=(int)((Math.random()*100)%54);

        String card1=new String("cards/"+String.valueOf(r1)+".png");
        String card2=new String("cards/"+String.valueOf(r2)+".png");
        String card3=new String("cards/"+String.valueOf(r3)+".png");
        String card4=new String("cards/"+String.valueOf(r4)+".png");

        ImageView imageView1 = readImageFromJar("cards.jar",card1);
        ImageView imageView2 = readImageFromJar("cards.jar",card2);
        ImageView imageView3 = readImageFromJar("cards.jar",card3);
        ImageView imageView4 = readImageFromJar("cards.jar",card4);

        String name1=getName(r1);
        String name2=getName(r2);
        String name3=getName(r3);
        String name4=getName(r4);
        Text t1=new Text(name1);
        Text t2=new Text(name2);
        Text t3=new Text(name3);
        Text t4=new Text(name4);

        pane.add(imageView1,0,0);
        pane.add(t1,0,1);
        pane.add(imageView2,1,0);
        pane.add(t2,1,1);
        pane.add(imageView3,2,0);
        pane.add(t3,2,1);
        pane.add(imageView4,3,0);
        pane.add(t4,3,1);

        Scene scene=new Scene(pane);
        primaryStage.setTitle("Mycard");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public String getName(int r){
        String name ="";
        if(r>=1 && r<=13)
            name+="黑桃";
        else if(r>=14 && r<=26)
            name+="红桃";
        else if(r>=27 && r<=39)
            name+="方块";
        else if(r>=40 && r<=52)
            name+="梅花";
        else if(r==53 || r==54) {
            name += "大王";
            return name;
        }

        HashMap<Integer,String> map = new HashMap<>();
        map.put(1, "A");  map.put(2, "2");
        map.put(3, "3");  map.put(4, "4");
        map.put(5, "5");  map.put(6, "6");
        map.put(7, "7");  map.put(8, "8");
        map.put(9, "9");  map.put(10, "10");
        map.put(11, "J");  map.put(12, "Q");
        map.put(0, "K");

        name+=map.get(r%13);
        return name;
    }

}

效果

我的计算器

描述

编程设计如图所示的界面。要求最后的界面布局尽可能接近效果图，不需要实现按钮功能。
注意有几个按钮的背景色有所不同。

设计思路

将窗口进行分块布局，总体采用边界窗格BorderPane，上边是文字部分，下边按钮采用网格窗格GridPane。

代码

package Conv.company;

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.geometry.VPos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;


public class calculator extends Application {

    @Override
    public void start(Stage primaryStage)
    {
        BorderPane pane = new BorderPane();
        TextField textField = new TextField("0");
        textField.setAlignment(Pos.BOTTOM_RIGHT);
        textField.setStyle("-fx-font: 22 Consolas;");
        pane.setTop(textField);
        pane.setBottom(getGrid());

        Scene scene = new Scene(pane);
        primaryStage.setScene(scene);
        primaryStage.setTitle("计算器");
        primaryStage.show();
    }


    private GridPane getGrid()
    {
        GridPane pane = new GridPane();
        pane.setAlignment(Pos.CENTER);
        pane.setHgap(5);
        pane.setVgap(5);

        pane.add(GetButton("MC", 40, 20), 0, 0);
        pane.add(GetButton("MR", 40, 20), 1, 0);
        pane.add(GetButton("MS", 40, 20), 2, 0);
        pane.add(GetButton("M+", 40, 20), 3, 0);
        pane.add(GetButton("M-", 40, 20), 4, 0);

        pane.add(GetButton("←", 40, 20), 0, 1);
        pane.add(GetButton("CE", 40, 20), 1, 1);
        pane.add(GetButton("C", 40, 20), 2, 1);
        pane.add(GetButton("±", 40, 20), 3, 1);
        pane.add(GetButton("√", 40, 20), 4, 1);


        Button b7 = GetButton("7", 40, 20);
        b7.setStyle("-fx-base: #bbffff");
        pane.add(b7, 0, 2);
        Button b8 = GetButton("8", 40, 20);
        b8.setStyle("-fx-base: #bbffff");
        pane.add(b8, 1, 2);
        Button b9 = GetButton("9", 40, 20);
        b9.setStyle("-fx-base: #bbffff");
        pane.add(b9, 2, 2);
        Button b4 = GetButton("4", 40, 20);
        b4.setStyle("-fx-base: #bbffff");
        pane.add(b4, 0, 3);
        Button b5 = GetButton("5", 40, 20);
        b5.setStyle("-fx-base: #bbffff");
        pane.add(b5, 1, 3);
        Button b6 = GetButton("6", 40, 20);
        b6.setStyle("-fx-base: #bbffff");
        pane.add(b6, 2, 3);
        Button b1 = GetButton("1", 40, 20);
        b1.setStyle("-fx-base: #bbffff");
        pane.add(b1, 0, 4);
        Button b2 = GetButton("2", 40, 20);
        b2.setStyle("-fx-base: #bbffff");
        pane.add(b2, 1, 4);
        Button b3 = GetButton("3", 40, 20);
        b3.setStyle("-fx-base: #bbffff");
        pane.add(b3, 2, 4);
        Button b0 = GetButton("0", 85, 20);
        b0.setStyle("-fx-base: #bbffff");
        GridPane.setValignment(b0, VPos.TOP);
        pane.add(b0, 0, 5, 2, 5);

        pane.add(GetButton("/", 40, 20), 3, 2);
        pane.add(GetButton("%", 40, 20), 4, 2);
        pane.add(GetButton("*", 40, 20), 3, 3);
        pane.add(GetButton("1/x", 40, 20), 4, 3);
        pane.add(GetButton("-", 40, 20), 3, 4);
        pane.add(GetButton("=", 40, 65), 4, 4, 4, 5);
        pane.add(GetButton(".", 40, 20), 2, 5);
        pane.add(GetButton("+", 40, 20), 3, 5);

        return pane;
    }

    private Button GetButton(String text,int width,int height){
        Button b = new Button(text);
        b.setPrefSize(width, height);
        return b;
    }
}