https://github.com/antkorwin/ioutils

utilities to work with MultipartFile and Temporary File in Spring Framework
https://github.com/antkorwin/ioutils

Last synced: 27 days ago
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utilities to work with MultipartFile and Temporary File in Spring Framework

• Host: GitHub
• URL: https://github.com/antkorwin/ioutils
• Owner: antkorwin
• Created: 2020-07-12T01:41:16.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2022-12-10T06:02:39.000Z (almost 2 years ago)
• Last Synced: 2023-07-26T21:15:15.390Z (over 1 year ago)
• Language: Java
• Size: 50.8 KB
• Stars: 4
• Watchers: 2
• Forks: 3
• Open Issues: 8
• Metadata Files:
  • Readme: README.adoc

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README

        
= IOUtils

:source-highlighter: prettify

:icons: font

:toc: top

:experimental:

:numbered:

== Dependencies

[source ,xml]

----

    com.antkorwin

    ioutils

    0.8

----

== Automatically deleted temp files in Java

There is a standard API to delete a temporary file in java:

[source, java]

----

File temp = File.createTempFile("filename", ".tmp");

temp.deleteOnExit();

----

But this file will be removed only after exit JVM,

if your application actively working with temporary files

then it can lead to the situation when a free space in the temp folder is over,

or sometimes you should restart your application just to clean the temp folder.

To resolve this problem you can use the `TempFile` from `ioutils`:

[source , java]

----

File tmp = TempFile.createEmpty();

----

this file will be deleted after a GC collecting the `tmp` object.

WARNING: Please use the temp file only by this file reference (`tmp` variable in the example above)

if you create a new reference to the temporary file using an absolute path

then you can’t read this file after GC collects the original reference.

Also, we can create non-empty files, creating a file from String:

[source, java]

----

File tmp = TempFile.createFromString("text file context");

----

an InputStream variant:

[source, java]

----

ByteArrayInputStream inputStream = new ByteArrayInputStream("file content".getBytes());

File file = TempFile.createFromInputStream(() -> inputStream);

----

And you can set an extension to files (`.tmp` by default):

[source, java]

----

File file = TempFile.createFromString("data file content", "txt");

----

== Read a file from resources in Java

To simplify working with files in the resource folder,

you can use the `ResourceFile` class.

You can read about the main methods in this class below,

or you can see in the unit test here: https://github.com/antkorwin/ioutils/blob/master/src/test/java/com/antkorwin/ioutils/resourcefile/ResourceFileTest.java[ResourceFileTest.java]

where describing all API of this class.

Read a file as String:

[source, java]

----

String content = new ResourceFile("filename_in_resource_folder.txt").readAsString();

----

read as a byte array:

[source, java]

----

byte[] content = new ResourceFile("/test.txt").readAsByteArray();

----

get a file from resource:

[source, java]

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File file = new ResourceFile("folder/nestedfile").getFile();

----

read an InputStream from a file in resources:

[source, java]

----

try (InputStream inputStream = new ResourceFile("test.txt").getInputStream()) {

    ...

}

----

write a content of file from resources to the OutputStream:

[source, java]

----

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

new ResourceFile("test.txt").write(() -> outputStream);

----