在java中创建一个rectangle类，使其有width,height两个属性，并且包含?两个方

public class Rectangle{
    private double width;
    private double height;
    public double area(){
        return width*height;
    }
    public double perimeter(){
        return (width+height)*2;
    }
    public Rectangle(){}
    public Rectangle(double width,double height){
        this.width=width;
        this.height=height;
    }
    public void setWidth(double width){
        this.width=width;
    }
    public double getWidth(){
        return width;
    }
    public double setHeight(double height){
        this.height=height;
    }
    public double getHeight(){
        return height;
    }
}
public class Test{
    public static void main(String... args){
        Rectangle a = new Rectangle();
        a.setWidth(width);//此处width填入你所需要的宽度
        a.setHeight(height);//此处height填入你所需要的高度
        Rectangle b = new Rectangle(width,height);//此处width与height分别填入你所需要的宽度与高度
        System.out.println(a.area());//a的面积
        System.out.println(a.perimeter());//a的周长
        System.out.println(b.area());//b的面积
        System.out.println(b.perimeter());//b的周长
    }
}

类Rectangle：

public class Rectangle {
	private double width;
	private double height;
	
	public Rectangle(){
		
	}
	
	public Rectangle(double width , double height){
		this.width = width;
		this.height = height;
	}
	
	public double area(){
		return width * height;
	}
	
	public double perimeter(){
		return 2 * (width + height);
	}
	
	// getter and setter
	public double getWidth() {
		return width;
	}
	public void setWidth(double width) {
		this.width = width;
	}
	public double getHeight() {
		return height;
	}
	public void setHeight(double height) {
		this.height = height;
	}

}

类Test：

public static void main(String[] args) {
		Rectangle recOne = new Rectangle();
		recOne.setWidth(200);
		recOne.setHeight(100);
		System.out.println("第一种方法计算周长和面积");
		System.out.println("周长：" + recOne.perimeter());
		System.out.println("面积：" + recOne.area());
		
		Rectangle recTwo = new Rectangle(200 , 100);
		System.out.println("第二种方法计算周长和面积");
		System.out.println("周长：" + recTwo.perimeter());
		System.out.println("面积：" + recTwo.area());
		
	}

Text 类：

public class Text {

public static void main(String[] args) {
Rectangle a=new Rectangle();
a.setWidth(2);
a.setHeight(3);
Rectangle b=new Rectangle(3,4);
System.out.println("面积："+a.area()+" 周长"+a.perimeter());
System.out.println("面积："+b.area()+" 周长"+b.perimeter());
}

}
Rectangle类：
private int width;
private int height;
public Rectangle(){

}
public Rectangle(int width,int height){
this.width=width;
this.height=height;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
public int area(){
return this.width*this.height;
}
public int perimeter(){
return (this.width+this.height)*2;
}