本文介紹了GetCanonicalPath和toRealPath之間的差異的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
是否存在File.getCanonicalPath()和File.toPath().toRealPath()會產生不同結果的情況？
他們似乎都做了非常相似的事情，但文檔從來沒有明確表示他們應該做同樣的事情。
在邊界案例中，我是否傾向于使用其中一種方法？
那么File.getAbsoltePath()和Path.toAbsoltePath()又如何呢–它們應該以相同的方式工作嗎？
推薦答案
結論：
getAbsolutePath和getPath從不失敗，因為它們不進行驗證
getCanonicalPathURL中的驅動器號無效或與當前文件夾不同時得出無效結果
toPath().toRealPath()正在檢查有效性，但該文件需要存在，并且還可以跟隨或不跟隨符號鏈接
toPath()足夠安全，不需要文件存在。
.toPath().toAbsolutePath().normalize()是最好的，不需要文件存在
我在Windows中對@John進行了類似的測試
@Test
public void testCanonical() throws IOException {
test("d:tarGet\..\Target", "File exist and drive letter is on the current one");
test("d:tarGet\..\Target\.\..\", "File exist and drive letter is on the current one, but parent of current drive should exist");
test("d:tarGet\non-existent\..\..\Target\.\..\", "Relative path contains non-existent file");
test("d:target\\file", "Double slash");
test("c:tarGet\..\Target\.", "File doesn't exist and drive letter is on different drive than the current one");
test("l:tarGet\..\Target\.\..\", "Drive letter doesn't exist");
test("za:tarGet\..\Target\.\..\", "Drive letter is double so not valid");
test("d:tarGet|Suffix", "Path contains invalid chars in windows (|)");
test("d:tarGetu0000Suffix", "Path contains invalid chars in both linux and windows (\0)");
}
private void test(String filename, String message) throws IOException {
java.io.File file = new java.io.File(filename);
System.out.println("Use: " + filename + " -> " + message);
System.out.println("F-GET: " + Try.of(() -> file.getPath()));
System.out.println("F-ABS: " + Try.of(() -> file.getAbsolutePath()));
System.out.println("F-CAN: " + Try.of(() -> file.getCanonicalPath()));
System.out.println("P-TO: " + Try.of(() -> file.toPath()));
System.out.println("P-ABS: " + Try.of(() -> file.toPath().toAbsolutePath()));
System.out.println("P-NOR: " + Try.of(() -> file.toPath().normalize()));
System.out.println("P-NOR-ABS: " + Try.of(() -> file.toPath().normalize().toAbsolutePath()));
System.out.println("P-ABS-NOR: " + Try.of(() -> file.toPath().toAbsolutePath().normalize()));
System.out.println("P-REAL: " + Try.of(() -> file.toPath().toRealPath()));
System.out.println("");
}
結果如下：
Use: d:tarGet..Target -> File exist and drive letter is on the current one
F-GET: Success(d:tarGet..Target)
F-ABS: Success(d:homeaiserworkestfs arGet..Target)
F-CAN: Success(D:homeaiserworkestfs arget)
P-TO: Success(d:tarGet..Target)
P-ABS: Success(D:homeaiserworkestfs arGet..Target)
P-NOR: Success(d:Target)
P-NOR-ABS: Success(D:homeaiserworkestfsTarget)
P-ABS-NOR: Success(D:homeaiserworkestfsTarget)
P-REAL: Success(D:homeaiserworkestfs arget)
Use: d:tarGet..Target... -> File exist and drive letter is on the current one, but parent of current drive should exist
F-GET: Success(d:tarGet..Target...)
F-ABS: Success(d:homeaiserworkestfs arGet..Target...)
F-CAN: Success(D:homeaiserworkestfs)
P-TO: Success(d:tarGet..Target...)
P-ABS: Success(D:homeaiserworkestfs arGet..Target...)
P-NOR: Success(d:)
P-NOR-ABS: Success(D:homeaiserworkestfs)
P-ABS-NOR: Success(D:homeaiserworkestfs)
P-REAL: Success(D:homeaiserworkestfs)
Use: d:tarGet
on-existent....Target... -> Relative path contains non-existent file
F-GET: Success(d:tarGet
on-existent....Target...)
F-ABS: Success(d:homeaiserworkestfs arGet
on-existent....Target...)
F-CAN: Success(D:homeaiserworkestfs)
P-TO: Success(d:tarGet
on-existent....Target...)
P-ABS: Success(D:homeaiserworkestfs arGet
on-existent....Target...)
P-NOR: Success(d:)
P-NOR-ABS: Success(D:homeaiserworkestfs)
P-ABS-NOR: Success(D:homeaiserworkestfs)
P-REAL: Success(D:homeaiserworkestfs)
Use: d:target\file -> Double slash
F-GET: Success(d:targetfile)
F-ABS: Success(d:homeaiserworkestfs argetfile)
F-CAN: Success(D:homeaiserworkestfs argetfile)
P-TO: Success(d:targetfile)
P-ABS: Success(D:homeaiserworkestfs argetfile)
P-NOR: Success(d:targetfile)
P-NOR-ABS: Success(D:homeaiserworkestfs argetfile)
P-ABS-NOR: Success(D:homeaiserworkestfs argetfile)
P-REAL: Failure(java.nio.file.NoSuchFileException: D:homeaiserworkestfs argetfile)
Use: c:tarGet..Target. -> File doesn't exist and drive letter is on different drive than the current one
F-GET: Success(c:tarGet..Target.)
F-ABS: Success(c:\tarGet..Target.)
F-CAN: Success(C:Target)
P-TO: Success(c:tarGet..Target.)
P-ABS: Success(C: arGet..Target.)
P-NOR: Success(c:Target)
P-NOR-ABS: Success(C:Target)
P-ABS-NOR: Success(C:Target)
P-REAL: Failure(java.nio.file.NoSuchFileException: C:Target)
Use: l:tarGet..Target... -> Drive letter doesn't exist
F-GET: Success(l:tarGet..Target...)
F-ABS: Success(l: arGet..Target...)
F-CAN: Success(L:)
P-TO: Success(l:tarGet..Target...)
P-ABS: Failure(java.io.IOError: java.io.IOException: Unable to get working directory of drive 'L')
P-NOR: Success(l:)
P-NOR-ABS: Failure(java.io.IOError: java.io.IOException: Unable to get working directory of drive 'L')
P-ABS-NOR: Failure(java.io.IOError: java.io.IOException: Unable to get working directory of drive 'L')
P-REAL: Failure(java.io.IOException: Unable to get working directory of drive 'L')
Use: za:tarGet..Target... -> Drive letter is double so not valid
F-GET: Success(za:tarGet..Target...)
F-ABS: Success(D:homeaiserworkestfsza:tarGet..Target...)
F-CAN: Success(D:homeaiserworkestfs)
P-TO: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
P-ABS: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
P-NOR: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
P-NOR-ABS: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
P-ABS-NOR: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
P-REAL: Failure(java.nio.file.InvalidPathException: Illegal char <:> at index 2: za:tarGet..Target...)
Use: d:tarGet|Suffix -> Path contains invalid chars in windows (|)
F-GET: Success(d:tarGet|Suffix)
F-ABS: Success(d:homeaiserworkestfs arGet|Suffix)
F-CAN: Failure(java.io.IOException: The filename, directory name, or volume label syntax is incorrect)
P-TO: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
P-ABS: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
P-NOR: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
P-NOR-ABS: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
P-ABS-NOR: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
P-REAL: Failure(java.nio.file.InvalidPathException: Illegal char <|> at index 8: d:tarGet|Suffix)
這篇關于GetCanonicalPath和toRealPath之間的差異的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，
