java 使用 f.delete() 方法删除现有文件

Deleting an existing file using f.delete() method

提问by Surya

String book_name = book_list.getModel().getElementAt(book_list.getSelectedIndex()).toString();
System.out.println("File name : "+book_name);

File f = new File("C:\Users\Surya\Documents\NetBeansProjects\New_Doodle\Library\"+book_name);
System.out.println("Path:"+f.getAbsolutePath());

if(f.exists())
    System.out.println("Book Exists");
else
    System.out.println("Not Exixts");

if(f.isFile())
{
    System.out.println("It is File");
}
else
    System.out.println("It is Directory");

System.out.println(f.isAbsolute());

if (f.delete())
{
    JOptionPane.showMessageDialog(null, "Book Deleted");
}
else
{
    JOptionPane.showMessageDialog(null, "Operation Failed");
}

Output

输出

File name : `Twilight03-Eclipse.pdf`  
Path: `C:\Users\Surya\Documents\NetBeansProjects\New_Doodle\Library\Twilight03-Eclipse.pdf`  
Book Exists  
It is File  
true  
Operation Failed (dialog box)  
File is not deleted

回答by Aniket Inge

Use the java.nio.filepackage to find out why your delete operation fails. It gives you a detailed reason for the same.

使用java.nio.file包找出删除操作失败的原因。它为您提供了相同的详细原因。

回答by Pheonix

A deletion may fail due to one or more reasons:

由于一种或多种原因，删除可能会失败：

• File does not exist (use File#exists() to test).
• File is locked (because it is opened by another app (or your own code!).
• You are not authorized (but that would have thrown a SecurityException, not returned false!).

• 文件不存在（使用 File#exists() 测试）。
• 文件被锁定（因为它被另一个应用程序（或您自己的代码！）打开。
• 您未获得授权（但这会引发 SecurityException，而不是返回 false！）。

This function could help:

此功能可以帮助：

public String getReasonForFileDeletionFailureInPlainEnglish(File file) {
    try {
        if (!file.exists())
            return "It doesn't exist in the first place.";
        else if (file.isDirectory() && file.list().length > 0)
            return "It's a directory and it's not empty.";
        else
            return "Somebody else has it open, we don't have write permissions, or somebody stole my disk.";
    } catch (SecurityException e) {
        return "We're sandboxed and don't have filesystem access.";
    }
}

How to tell why a file deletion fails in Java?

如何判断为什么在 Java 中文件删除失败？

回答by Lokesh Kumar

public class Example {
    public static void main(String[] args) {
         try{
             File file = new File("C:/ProgramData/Logs/" + selectedJLItem);

             if(file.delete()){
                 System.out.println(file.getName() + " Was deleted!");
             }else{
                 System.out.println("Delete Operation Failed. Check: " + file);
             }
         }catch(Exception e1){
             e1.printStackTrace();
         }
    }
}