java - 为什么文件没有删除？输入/输出

Question

你好，盖伊兹，我有一种方法可以加密我的应用程序中的文件，我想加密文件并删除源代码，我尝试了这样的方法，但它不起作用..？

 public static void encrypt(String password, InputStream is, OutputStream os,String DelFile) throws Exception {

SecretKeySpec keySpec = new SecretKeySpec(password(password), "TripleDES");
Cipher cipher = Cipher.getInstance("TripleDES");
cipher.init(Cipher.ENCRYPT_MODE, keySpec);
byte[] buf = new byte[8096];
os = new CipherOutputStream(os, cipher);
int numRead = 0;
while ((numRead = is.read(buf)) >= 0) {
    os.write(buf, 0, numRead);
}
os.close();

// file deleting part...
File f = new File(DelFile);
f.delete();}

这个f.delete();应该删除这个文件吗？我对吗？但它不会工作，请指教，谢谢。

Answer 1

要么针对该文件打开了输入流，要么未给出完整文件名(以及路径)。这就是 File 的 delete() 方法对于查找不删除的实际原因不太有用的原因。如果你看一下它的docs

Deletes the file or directory denoted by this abstract pathname. Ifthis pathname denotes a directory, then the directory must be empty inorder to be deleted. Note that the Files class defines the deletemethod to throw an IOException when a file cannot be deleted. This isuseful for error reporting and to diagnose why a file cannot bedeleted.

因此，这里是帮助您找到根本原因的建议。使用Files.delete()删除方法。

抛出:

NoSuchFileException - if the file does not exist (optional specificexception)

DirectoryNotEmptyException - if the file is a directory andcould not otherwise be deleted because the directory is not empty(optional specific exception)

IOException - if an I/O error occurs

SecurityException - In the case of the default provider, and asecurity manager is installed, the SecurityManager.checkDelete(String)method is invoked to check delete access to the file

看到它抛出的异常，你就可以找出根本原因是什么。