定义一个名为Rectangle的类表示矩形 java

public class Rectangle {
private double length;
private double width;

public Rectangle(double length, double width) {
this.length = length;
this.width = width;
}

public double getLength() {
return length;
}

public void setLength(double length) {
this.length = length;
}

public double getWidth() {
return width;
}

public void setWidth(double width) {
this.width = width;
}

public double getArea() {
return length * width;
}

public double getPerimeter() {
return 2 * (length + width);
}
}