错误：课堂课本中找不到Main方法，请将Main方法定义为：public static void Main（String[]args)

Question

我试着编译它，它说没有错误。但当我运行程序时，它说：

import java.util.*;

public class Book

{
private int pageNum;
private String title;
Date today = new Date();

    public Book(int pn, String name)
    {
    pageNum = pn;
    title = name;
    }

    //Setter/Getter for pageNum
    public int getpageNum()
    {
    return pageNum;
    }

    public void setpageNum(int pn)
    {
    pageNum = pn;
    }
    //Setter/Getter for Title
    public String getTitle()
    {
    return title;
    }

    public void setTitle(String name)
    {
    title = name;
    }

    public void display()
    {
    System.out.println("Book.java" + "\nby Tyler " + today);
    System.out.println("Book Title: " + title + "\nNumber of Pages: " + pageNum);
    }
}

public class TextBook extends Book
{
private String gradeLevel;

public TextBook(int pageNum, String title, String gl)
    {
    super(pageNum, title);
    gradeLevel = gl;
    }

    //Setter/Getter for gradeLevel
    public String getGradeLevel()
    {
    return gradeLevel;
    }

    public void setGradeLevel(String g)
    {
    gradeLevel = g;
    }

    public void display()
    {
    super.display();
    System.out.println("Grade Level: " + gradeLevel);
    }

}

public class DemoBook
{
    public static void main(String[] args)
    {
    Book oneBook = new Book(250, "Awesome Story");
    TextBook oneTextBook = new TextBook(350, "Awesomer Story", "12");

    oneBook.display();
    oneTextBook.display();
    }
}

Answer 1

您只能使用main方法运行java文件。

在您的情况下，只能运行demobook.java