java Class Inflater call from Matlab Command Window

Question

Stefano Gianoli 2016-11-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/313672-java-class-inflater-call-from-matlab-command-window

编辑： Stefano Gianoli 2016-11-25

在 MATLAB Online 中打开

From Java documentation on the web page:

Inflater (Java Platform SE 7)

I can get the following code compiled and running in java:

// Encode a String into bytes
String inputString = "blahblahblah??";
byte[] input = inputString.getBytes("UTF-8");
// Compress the bytes
byte[] output = new byte[100];
Deflater compresser = new Deflater();
compresser.setInput(input);
compresser.finish();
int compressedDataLength = compresser.deflate(output);

However, when I am writing this appropriately adapted for Matlab Command Window:

import java.util.zip.Inflater
% Encode a String into bytes
inputString = javaObject('java.lang.String','blahblahblah??');
input = inputString.getBytes('UTF-8');
%  Compress the bytes
output = javaArray('java.lang.Byte',100);
compresser = java.util.zip.Deflater();
compresser.setInput(input);
compresser.finish();
compressedDataLength = compresser.deflate(output);

I got for the last line of code the following error message:

No method 'deflate' with matching signature found for class 'java.util.zip.Deflater'.

The signature of the class is the correct one as it takes

java.lang.Byte[]

as it can be seen with the command:

methodsview(compresser)

Any ideas why does not work?

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Answer 1

Stefano Gianoli 2016-11-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/313672-java-class-inflater-call-from-matlab-command-window#answer_244655

编辑：Stefano Gianoli 2016-11-25

在 MATLAB Online 中打开

The following Matlab newsreader threads:

Using of java.util.zip.GZIPOutputStream

Help needed with Java interface with Matlab

as well as the in these threads mentioned Matlab File Exchange contributions:

Rapid lossless data compression of numerical or string variables

Compression Routines

plus this Matlab File exchange contribution:

Byte encoding utilities

addressed me to a possible workaround.

Workaround: Use java.io.ByteArrayOutputStream() and java.util.zip.DeflaterOutputStream(,)

import java.util.zip.Inflater
% Encode a String into bytes
inputString = javaObject('java.lang.String','blahblahblah??');
input       = inputString.getBytes('UTF-8');
%  Compress the bytes
output      = java.io.ByteArrayOutputStream();
compresser  = java.util.zip.Deflater();
outstrm     = java.util.zip.DeflaterOutputStream(output,compresser);
outstrm.write(input);
compresser.finish();
outstrm.close();
% output to ByteArray
output.toByteArray()
% output to String
output.toString()