How to use java.nio in MATLAB?

2018 12 26
1 个回答
回答已采纳
更新时间：2018 12 30
11 次查看（30 天）

 采纳的回答

Kojiro Saito
Kojiro Saito 2018-12-27

2 个投票

Here is two example of deleting a file using java.nio.file.
%% Method1
str = fullfile(pwd, 'test1.txt' );
%jpath1 = java.nio.file.Paths.get(str) % not works
jpath1 = java.nio.file.Paths.get(str, javaArray('java.lang.String', 0)); % works
java.nio.file.Files.delete(jpath1)
%% Method2
jpath2 = java.nio.file.Paths.get(pwd, 'test2.txt');
java.nio.file.Files.delete(jpath2)
I've tested in MATLAB R2018b on Windows 10.
As you may know, from R2017b, MATLAB's JVM was changed to Java 8. So, java.nio.file.Files.delete used in MATLAB R2017b ~ R2018b is that of Java 8.
https://docs.oracle.com/javase/8/docs/api/java/nio/file/Files.html#delete-java.nio.file.Path-

4 个评论
显示 2更早的评论 隐藏 2更早的评论

bbb_bbb
bbb_bbb 2018-12-27
编辑：bbb_bbb 2018-12-27
Thank you.
java.nio.file.Files is also part of Java 7, which is available in MATLAB R2013b (8.2) or newer. I use R2015.
Method2 works, but Method1 does not:
str = fullfile(pwd, 'test1.txt' );
jpath1 = java.nio.file.Paths.get(str, javaArray('java.lang.String', 0))
Error using javaArray
All dimension arguments must be greater than zero
The problem is that before I used
java.io.File(['\\?\' filename]).delete
where filename is full file name (e.g. 'C:\myfiles\test1.txt'),
and it worked fine.
That UNC-path prefix ('\\?\') was used to work with unusual files which are not processed by conventional methods (with specific characters in their names).
If I use the Method2 with that pathname:
jpath2 = java.nio.file.Paths.get(['\\?\' pwd], 'test2.txt')
Java exception occurred:
java.nio.file.InvalidPathException: Illegal character [?] in path at index 2: \\?\C:\myfiles\test2.txt
at sun.nio.fs.WindowsPathParser.nextSlash(Unknown Source)
at sun.nio.fs.WindowsPathParser.parse(Unknown Source)
at sun.nio.fs.WindowsPathParser.parse(Unknown Source)
at sun.nio.fs.WindowsPath.parse(Unknown Source)
at sun.nio.fs.WindowsFileSystem.getPath(Unknown Source)
at java.nio.file.Paths.get(Unknown Source)
So, is there any way to use UNC-path with java.nio?
What is the problem with Method1 that you proposed?
bbb_bbb
bbb_bbb 2018-12-29
Btw, how to determine the success of the operation:
java.nio.file.Files.delete(jpath2)
Kojiro Saito
Kojiro Saito 2018-12-29
>> Btw, how to determine the success of the operation:
I would simply use "try catch".
try
java.nio.file.Files.delete(jpath2)
catch ME
% When delete was failed, do some error handle
error(ME.message)
end
% When delete was successful
msgbox('Successfully deleted')
bbb_bbb
bbb_bbb 2018-12-30
ME.message - gives error...

请先登录，再进行评论。

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Cell Arrays 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by