Java-使用类并读取文件

Question

我正在编写一个程序，它有四个类:Circle、Rectangle、GeometricObject 和我的主要类 TestGeometricObject。 我不明白如何使用 TestGeometricObject 从另一个文件(例如记事本)读取？

我不需要帮助阅读类(class)，我现在只需要帮助，如何连接我必须读取的另一个文件(例如记事本上的文件)，不仅仅是这个程序，而是我要编写的任何程序？我希望这是有道理的...如果没有，请告诉我。

 public class TestGeometricObject {
         public static void main(String[] args) {

        GeometricObject geoObject1 = new Circle();

    GeometricObject geoObject2 = new Rectangle();

    System.out.println("The two objects have the same area? " +
      equalArea(geoObject1, geoObject2));

    // Display circle
    displayGeometricObject(geoObject1);

    // Display rectangle
    displayGeometricObject(geoObject2);
  }



public static boolean equalArea(GeometricObject object1,GeometricObject object2) {

    return object1.getArea() == object2.getArea();
  }
  public static void displayGeometricObject(GeometricObject object) {
    System.out.println();
    System.out.println("The area is " + object.getArea());
    System.out.println("The perimeter is " + object.getPerimeter());
  }
}//end main

    public class Circle extends GeometricObject {
      private double radius;

      public Circle() {
      }

      public Circle(double radius) {
        this.radius = radius;
      }

      /** Return radius */
      public double getRadius() {
        return radius;
      }

      /** Set a new radius */
      public void setRadius(double radius) {
        this.radius = radius;
      }

   /** Return area */


        public double getArea() {
            return radius * radius * Math.PI;
          }

          /** Return diameter */
          public double getDiameter() {
            return 2 * radius;
          }

     /** Return perimeter */
          public double getPerimeter() {
            return 2 * radius * Math.PI;
          }

          /* Print the circle info */
          public void printCircle() {
            System.out.println("The circle is created " + getDateCreated() +
              " and the radius is " + radius);
          }
        }//end

    public class Rectangle extends GeometricObject {
      private double width;
      private double height;

      public Rectangle() {
      }

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

      /** Return width */
      public double getWidth() {
        return width;
      }

      /** Set a new width */
      public void setWidth(double width) {
        this.width = width;
      }

      /** Return height */
      public double getHeight() {
        return height;
      }

      /** Set a new height */
      public void setHeight(double height) {
        this.height = height;
      }
    /** Return area */
      public double getArea() {
        return width * height;
      }

     /** Return perimeter */
      public double getPerimeter() {
        return 2 * (width + height);
      }
    }//end

public abstract class GeometricObject {
  private String color = "white";
  private boolean filled;
  private java.util.Date dateCreated;

  /** Construct a default geometric object */
  protected GeometricObject() {
    dateCreated = new java.util.Date();
  }

  /** Construct a geometric object with color and filled value */
  protected GeometricObject(String color, boolean filled) {
    dateCreated = new java.util.Date();
    this.color = color;
    this.filled = filled;
  }

  /** Return color */
  public String getColor() {
    return color;
  }

  /** Set a new color */
  public void setColor(String color) {
    this.color = color;
  }

  /** Return filled. Since filled is boolean,
   *  the get method is named isFilled */
  public boolean isFilled() {
    return filled;
  }

  /** Set a new filled */
  public void setFilled(boolean filled) {
    this.filled = filled;
  }

  /** Get dateCreated */
  public java.util.Date getDateCreated() {
    return dateCreated;
  }


  public String toString() {
    return "created on " + dateCreated + "\ncolor: " + color +
      " and filled: " + filled;
  }

  /** Abstract method getArea */
  public abstract double getArea();

  /** Abstract method getPerimeter */
  public abstract double getPerimeter();
}//end

Answer 1

要读取文本文件，通常的做法是使用 BufferedReader 包装器和 FileReader

try {
  BufferedReader br = new BufferedReader(new FileReader(new File("yourFile.txt")));
  String line;
  while ((line = br.readLine()) != null) {
    System.out.println(line);
  }
  br.close();
} catch (IOException e) {
  e.printStackTrace();
}