Re: [Jython-users] File write and read

[Lauri L. <pu...@su...>]

Isn't that below my first example, where I do use BufferedInputStream? 
Or did you mean something else?

Jeff Emanuel wrote:

> Because it does a physical I/O operation for every byte.
> You need to wrap the file streams with buffered streams,
> for example:
>
> bi = BufferedInputStream(FileInputStream(File(filename)))
>
>
> Lauri Lehtinen wrote:
>
>> Setting to use the binary mode worked!
>>
>> Does any one know why java variant of this in jython performs very 
>> poorly?
>>
>> Here the basic java variant:
>> ---
>> from java.net import *
>> from java.io import *
>> def copy(filename):
>>    bi = FileInputStream(File(filename))
>>    bo = FileOutputStream(File(filename+".copy"))
>>    b = [1000000]
>>    while 1:
>>        l = bi.read(b)
>>        if l == -1:
>>            break
>>        bo.write(b)              bo.close()
>>    bi.close()
>>    return 1
>>           if __name__ == "__main__":          i = raw_input("Give 
>> file:")
>>    copy(i)
>> ---
>> That berforms only about 10kB/s, here one that uses buffers and 
>> performs better:
>> ---
>> from java.net import *
>> from java.io import *
>> def copy(filename):
>>    bi = BufferedInputStream(FileInputStream(File(filename)))
>>    bo = BufferedOutputStream(FileOutputStream(File(filename+".copy")))
>>    while 1:
>>        l = bi.read()
>>        if l == -1:
>>            break
>>        bo.write(l)              bo.close()
>>    bi.close()
>>    return 1
>>           if __name__ == "__main__":          i = raw_input("Give 
>> file:")
>>    copy(i)
>> ---
>> This performs about 600kB/s what isn't good at all, that should be 
>> much better. I tried also by using static buffer size but that 
>> performed even poorly for some reason. Why the performance is so bad?
>>
>> Sincerely,
>> Lauri Lehtinen
>>
>> Kent Johnson wrote:
>>
>>> Lauri Lehtinen wrote:
>>>
>>>> Hi,
>>>>
>>>> I just noticed this, when I have this kind of code:
>>>> ---
>>>> def copyFile(filename):
>>>>    bi = open(filename)
>>>>    bo = open(filename+'.copy', 'w')
>>>>    b = 1000000
>>>>    while 1:
>>>>        l = bi.read(b)
>>>>        if len(l) == 0:
>>>>            break
>>>>        bo.write(l)
>>>>    bo.close()
>>>>    bi.close()
>>>>    return 1
>>>>           i = raw_input("Give file:")
>>>> copyFile(i)
>>>> ---
>>>> and e.g. copy mp3 file with it the .copy mp3 file is somehow mixed 
>>>> and not working as it should, but when I run this with plain python 
>>>> it works just as it should. How to fix or workaround this? Is thus 
>>>> known bug?
>>>
>>>
>>>
>>>
>>> Maybe you need to use binary mode?
>>>    bi = open(filename, 'b')
>>>    bo = open(filename+'.copy', 'wb')
>>>
>>> How do the two files differ?
>>>
>>> Kent
>>>
>>>>
>>>> I have tried to make the same using java's FileInputStream and 
>>>> FileOutputStream but then the performance is then very bad (about 
>>>> 500kB/s). Is that also known issue?
>>>>
>>>> Sincerely,
>>>> Lauri Lehtinen
>>>>
>>>>
>>>>
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>>>
>>>
>>>
>>>
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>>
>>
>>
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>
>
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