Java问题，为什么运行结果会有Boolean值

Question

import java.io.*;

class File_Manage{

public static void main(String[] args) throws IOException{

File dir_Books = new File("C:/Books");

File file_Book1 = new File(dir_Books, "Book1.txt");

if(!dir_Books.exists()){

System.out.print(dir_Books.getName()+"是否建立成功? ");

System.out.println(dir_Books.mkdirs()); 

}

else

System.out.println(dir_Books.getName() + "已存在");

if(!file_Book1.exists()){

System.out.print(file_Book1.getName()+"是否建立成功? ");

System.out.println(file_Book1.createNewFile()); 

//file.deleteOnExit();

}

else

System.out.println(file_Book1.getName() + "文件已存在");

File file_Book2 = new File(file_Book1.getParent(), "Book2.txt");

System.out.println(file_Book1.getName() + "改名为" + file_Book2.getName());

System.out.print("是否修改成功? ");

System.out.println(file_Book1.renameTo(file_Book2));

System.out.print(file_Book2.getName() + "是否删除成功? ");

System.out.println(file_Book2.delete());

System.out.print(dir_Books.getName() + "是否删除成功? ");

System.out.println(dir_Books.delete());

}

}

Answer 1

mkdirs(),createNewFile(),delete()方法的返回值都是boolean值你可以自己看一下他们每个方法的返回值