javaSE_8系列博客——Java语言的特性（三）--类和对象（8）--对象

典型的Java程序会创建许多对象，如您所知，通过调用方法进行交互。通过这些对象交互，程序可以执行各种任务，例如实现GUI，运行动画，或通过网络发送和接收信息。一旦一个对象完成了创建它的工作，它的资源将被再循环供其他对象使用。

这是一个名为CreateObjectDemo的小程序，它创建三个对象：一个Point对象和两个Rectangle对象。您将需要所有三个源文件来编译此程序。

source code for Point：

public class Point{    private int x;    private int y;    public int GetX(){        return x;    }    public int GetY(){        return y;    }    public void SetX(int x){        this.x = x;    }    public void SetY(int y){        this.y = y;    }    public Point(int x,int y){        this.x = x;        this.y = y;    }}

Source Code For Rectangle:

public class Rectangle{    private int width = 0;    public int GetWidth(){            return width;    }    public void SetWidth(int width){        this.width = width;    }    private int height = 0;    public int GetHeight(){        return height;    }    public void SetHeight(int height){        this.height = height;    }    public Point origin;    public Rectangle(){        origin = new Point(0,0);    }    public Rectangle(int width,int height){        SetWidth(width);        SetHeight(height);    }    public Rectangle(Point origin,int width,int height){        this.origin = origin;        SetWidth(width);        SetHeight(height);    }    public  int getArea(){        return width * height;    }    public void move(int x, int y ){        this.origin.SetX(x);        this.origin.SetY(y);    }}

Source Code For CreateObjectDemo:

public class CreateObjectDemo{    public static void main(String[] args){        Point originOne = new Point(23,94);        Rectangle rectOne = new Rectangle(originOne,100,200);        Rectangle rectTwo = new Rectangle(50,100);        System.out.println("Width of rectOne: " + rectOne.GetWidth());        System.out.println("Height of rectOne: " + rectOne.GetHeight());        System.out.println("Area of rectOne: " + rectOne.getArea());        rectTwo.origin = originOne;        System.out.println("x Position of rectTwo： " + rectTwo.origin.GetX());        System.out.println("y Position of rectTwo： " + rectTwo.origin.GetY());        rectTwo.move(40,72);        System.out.println("x Position of rectTwo： " + rectTwo.origin.GetX());        System.out.println("y Position of rectTwo： " + rectTwo.origin.GetY());    }}

这个程序的输出结果为：

Width of rectOne: 100Height of rectOne: 200Area of rectOne: 20000X Position of rectTwo: 23Y Position of rectTwo: 94X Position of rectTwo: 40Y Position of rectTwo: 72

接下来的文章，我们将使用上述示例来描述程序中对象的生命周期。从他们，您将学习如何编写在自己的程序中创建和使用对象的代码。您还将了解一个对象在生命结束后如何清理系统。