private ArrayList<String> comments怎么创建对象

要创建一个 `ArrayList` 对象，你可以使用以下代码：

ArrayList<String> comments = new ArrayList<String>();

这将创建一个名为 `comments` 的 `ArrayList` 对象，其中每个元素都是一个字符串。如果你希望在创建对象时添加一些元素，可以使用以下代码：

ArrayList<String> comments = new ArrayList<String>(Arrays.asList("comment1", "comment2", "comment3"));

这将创建一个包含三个字符串元素的 `ArrayList` 对象，并将其分配给名为 `comments` 的变量。

相关问题

A Circleobject consists ofa radius. When adding a height to a circle object, a Cylinderobject can be made. A Cylinderobject consists ofa radiusand a height. A default circlecontains a radiusof 1. A default cylindercontains a radiusof 1 and a heightof 1. Assume that both radiusand heightare non-negative integers.Designand implementCircleclass and Cylinderclass. Class Circlemust be the superclass of class Cylinder. Class Circlecannothave any superclass except the ultimate superclass Object. When instantiating the two classes, circles and cylinders can be made and stored in an array list as shown below. publicstaticvoidmain(String[] args){ArrayList<Circle> shapes = newArrayList<Circle>();//Creates a list of circles and cylinders.shapes.add(newCircle());shapes.add(newCircle(5));shapes.add(newCylinder());shapes.add(newCylinder(10,5));//Prints the list.for(Circle next: shapes){System.out.println(next);} }a.Draw an UML diagram to show the design. Visibility modifiers, void/value return type, names, and parameter types are required. (10 points)b.Implement both classes by including only the following members in each of the classes.(35 points each class. 70pointsin total)•instance variables•overloading constructors•getters/setters•overriding toString•overriding equals You must use thisreference and superreference when appropriate. Correct Java syntax is required. No Javadoc style comments are required.

a. 下面是 Circle 类和 Cylinder 类的 UML 图：

+--------------------------------+
|             Circle             |
+--------------------------------+
| - radius: int                  |
+--------------------------------+
| + Circle()                     |
| + Circle(radius: int)          |
| + getRadius(): int             |
| + setRadius(radius: int): void |
| + getArea(): double            |
| + toString(): String           |
| + equals(obj: Object): boolean |
+--------------------------------+

           ^
           |
           |
           |
           |
           |
           |
+--------------------------------+
|            Cylinder            |
+--------------------------------+
| - height: int                  |
+--------------------------------+
| + Cylinder()                   |
| + Cylinder(radius: int, height: int)|
| + getHeight(): int             |
| + setHeight(height: int): void |
| + getVolume(): double          |
| + toString(): String           |
| + equals(obj: Object): boolean |
+--------------------------------+

b. 下面是 Circle 类的实现：

public class Circle {
    private int radius;

    public Circle() {
        this.radius = 1;
    }

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

    public int getRadius() {
        return radius;
    }

    public void setRadius(int radius) {
        this.radius = radius;
    }

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

    @Override
    public String toString() {
        return "Circle[radius=" + radius + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Circle) {
            Circle other = (Circle) obj;
            return radius == other.radius;
        }
        return false;
    }
}

下面是 Cylinder 类的实现：

public class Cylinder extends Circle {
    private int height;

    public Cylinder() {
        super();
        this.height = 1;
    }

    public Cylinder(int radius, int height) {
        super(radius);
        this.height = height;
    }

    public int getHeight() {
        return height;
    }

    public void setHeight(int height) {
        this.height = height;
    }

    public double getVolume() {
        return super.getArea() * height;
    }

    @Override
    public String toString() {
        return "Cylinder[radius=" + getRadius() + ",height=" + height + "]";
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Cylinder) {
            Cylinder other = (Cylinder) obj;
            return super.equals(other) && height == other.height;
        }
        return false;
    }
}

在这两个类中，我们使用了继承、多态、重载构造函数、封装等面向对象编程的概念，同时重写了 `toString` 和 `equals` 方法，以便可以在输出和比较对象时得到更加友好的结果。

java读取yaml文件内容包括注释

Java读取YAML文件内容包括注释可以通过以下步骤实现：

1. 引入YAML解析库，如jyaml或snakeyaml。

2. 使用YAML解析库读取YAML文件内容。

3. 将读取到的内容存储到一个Map对象中，其中包含键值对和注释。

以下是一个示例代码：

import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.reader.StreamReader;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.*;

public class YamlReader {

    public static void main(String[] args) {
        Yaml yaml = new Yaml();
        try {
            InputStream stream = new FileInputStream("test.yaml");
            Map<String, Object> document = (Map<String, Object>) yaml.load(stream);
            Map<String, List<String>> comments = extractComments(stream);
            for (Map.Entry<String, Object> entry : document.entrySet()) {
                String key = entry.getKey();
                Object value = entry.getValue();
                List<String> commentList = comments.get(key);
                if (commentList != null) {
                    for (String comment : commentList) {
                        System.out.println(comment);
                    }
                }
                System.out.println(key + ": " + value);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    private static Map<String, List<String>> extractComments(InputStream stream) {
        Map<String, List<String>> comments = new HashMap<>();
        try {
            StreamReader reader = new StreamReader(stream);
            while (reader.hasMore()) {
                Node node = reader.peekNode();
                if (node != null && node.getStartMark().getColumn() == 0 && node.getEndMark().getColumn() == 0) {
                    List<String> commentList = new ArrayList<>();
                    while (node != null && node.getStartMark().getColumn() == 0 && node.getEndMark().getColumn() == 0) {
                        commentList.add(reader.getNextLine());
                        node = reader.peekNode();
                    }
                    comments.put(node.getStartMark().getLine() + "", commentList);
                } else {
                    reader.getNextLine();
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return comments;
    }
}

在这个示例中，我们使用了SnakeYAML库来读取YAML文件内容，并使用extractComments方法从文件中提取注释。在主方法中，我们遍历读取到的内容，根据每个键值对的键从注释Map中获取注释，并将注释和值一起输出。