BufferedReader do not read the entire text file









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1
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I read about someone having troubles with BufferedReader: the reader simply do not read the first lines. I have instead the opposite problem. For example, in a text file with 300 lines, it arrives at 200, read it half of it and then the following string is given null, so it stops.



private void readerMethod(File fileList) throws IOException 
BigInteger steps = BigInteger.ZERO;
BufferedReader br = new BufferedReader(new FileReader(fileList));

String st;
//reading file line by line
try
while (true)
st = br.readLine();
if(st == null)
System.out.println("Null string at line " + steps);
break;

System.out.println(steps + " - " + st);
steps = steps.add(BigInteger.ONE);

catch(Exception e)
e.printStackTrace();

finally
try
br.close();
catch(Exception e)




The output of the previous slice of code is as expected until it reaches line 199 (starting from 0). Consider a file with 300 lines.



...
198 - 3B02D5D572B66A82F9D21EE809320DB3E250C6C9
199 - 6E2C69795CB712C27C4097119CE2C5765
Null string at line 200



Notice that, all lines have the same length, so in this output line 199 is not even complete. I checked the file text, and it's correct: it contains all 300 lines and they are all of the same length. Also, in the text there are only capitals letters and numbers, as you can see.



My question is: how can i fix this? I need that the BufferedReader read all the text, not just a part of it.



As someone asked i add here the remaining part of the code. Please notice that all capital names are constant of various type (int, string etc).
This is the method that is called by the main thread:



public void init()
BufferedWriter bw = null;
List<String> allLines = createRandomStringLines(LINES);
try
String fileName = "SHA1_encode_text.txt";
File logFile = new File(fileName);
System.out.println(logFile.getCanonicalPath());
bw = new BufferedWriter(new FileWriter(logFile));

for(int i = 0; i < allLines.size(); i++)
//write file
String o = sha1FromString(allLines.get(i));
//sha1FromString is a method that change the aspect of the string,
//replacing char by char. Is not important at the moment.
bw.write(o + "n");


catch(Exception e)
e.printStackTrace();
finally
try
bw.close();
catch(Exception e)





The method that create the list of random string is the following. "SYMBOLS" is just a String contains all avaiable chars.



private List<String> createRandomStringLines(int i) 
List<String> list = new ArrayList<String>();
while(i!=0)
StringBuilder builder = new StringBuilder();
int count = 64;
while (count-- != 0)
int character = (int)(Math.random()*SYMBOLS.length());
builder.append(SYMBOLS.charAt(character));

String generatedString = builder.toString();
list.add(generatedString);
i--;

return list;



Note that, the file written is totally correct.










share|improve this question



















  • 1




    When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
    – Mickael
    Nov 9 at 9:22






  • 2




    Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
    – ygor
    Nov 9 at 9:41







  • 1




    The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
    – Robert Kock
    Nov 9 at 9:55






  • 1




    Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
    – ygor
    Nov 9 at 10:01






  • 1




    BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
    – ygor
    Nov 9 at 10:07














up vote
1
down vote

favorite
1












I read about someone having troubles with BufferedReader: the reader simply do not read the first lines. I have instead the opposite problem. For example, in a text file with 300 lines, it arrives at 200, read it half of it and then the following string is given null, so it stops.



private void readerMethod(File fileList) throws IOException 
BigInteger steps = BigInteger.ZERO;
BufferedReader br = new BufferedReader(new FileReader(fileList));

String st;
//reading file line by line
try
while (true)
st = br.readLine();
if(st == null)
System.out.println("Null string at line " + steps);
break;

System.out.println(steps + " - " + st);
steps = steps.add(BigInteger.ONE);

catch(Exception e)
e.printStackTrace();

finally
try
br.close();
catch(Exception e)




The output of the previous slice of code is as expected until it reaches line 199 (starting from 0). Consider a file with 300 lines.



...
198 - 3B02D5D572B66A82F9D21EE809320DB3E250C6C9
199 - 6E2C69795CB712C27C4097119CE2C5765
Null string at line 200



Notice that, all lines have the same length, so in this output line 199 is not even complete. I checked the file text, and it's correct: it contains all 300 lines and they are all of the same length. Also, in the text there are only capitals letters and numbers, as you can see.



My question is: how can i fix this? I need that the BufferedReader read all the text, not just a part of it.



As someone asked i add here the remaining part of the code. Please notice that all capital names are constant of various type (int, string etc).
This is the method that is called by the main thread:



public void init()
BufferedWriter bw = null;
List<String> allLines = createRandomStringLines(LINES);
try
String fileName = "SHA1_encode_text.txt";
File logFile = new File(fileName);
System.out.println(logFile.getCanonicalPath());
bw = new BufferedWriter(new FileWriter(logFile));

for(int i = 0; i < allLines.size(); i++)
//write file
String o = sha1FromString(allLines.get(i));
//sha1FromString is a method that change the aspect of the string,
//replacing char by char. Is not important at the moment.
bw.write(o + "n");


catch(Exception e)
e.printStackTrace();
finally
try
bw.close();
catch(Exception e)





The method that create the list of random string is the following. "SYMBOLS" is just a String contains all avaiable chars.



private List<String> createRandomStringLines(int i) 
List<String> list = new ArrayList<String>();
while(i!=0)
StringBuilder builder = new StringBuilder();
int count = 64;
while (count-- != 0)
int character = (int)(Math.random()*SYMBOLS.length());
builder.append(SYMBOLS.charAt(character));

String generatedString = builder.toString();
list.add(generatedString);
i--;

return list;



Note that, the file written is totally correct.










share|improve this question



















  • 1




    When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
    – Mickael
    Nov 9 at 9:22






  • 2




    Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
    – ygor
    Nov 9 at 9:41







  • 1




    The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
    – Robert Kock
    Nov 9 at 9:55






  • 1




    Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
    – ygor
    Nov 9 at 10:01






  • 1




    BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
    – ygor
    Nov 9 at 10:07












up vote
1
down vote

favorite
1









up vote
1
down vote

favorite
1






1





I read about someone having troubles with BufferedReader: the reader simply do not read the first lines. I have instead the opposite problem. For example, in a text file with 300 lines, it arrives at 200, read it half of it and then the following string is given null, so it stops.



private void readerMethod(File fileList) throws IOException 
BigInteger steps = BigInteger.ZERO;
BufferedReader br = new BufferedReader(new FileReader(fileList));

String st;
//reading file line by line
try
while (true)
st = br.readLine();
if(st == null)
System.out.println("Null string at line " + steps);
break;

System.out.println(steps + " - " + st);
steps = steps.add(BigInteger.ONE);

catch(Exception e)
e.printStackTrace();

finally
try
br.close();
catch(Exception e)




The output of the previous slice of code is as expected until it reaches line 199 (starting from 0). Consider a file with 300 lines.



...
198 - 3B02D5D572B66A82F9D21EE809320DB3E250C6C9
199 - 6E2C69795CB712C27C4097119CE2C5765
Null string at line 200



Notice that, all lines have the same length, so in this output line 199 is not even complete. I checked the file text, and it's correct: it contains all 300 lines and they are all of the same length. Also, in the text there are only capitals letters and numbers, as you can see.



My question is: how can i fix this? I need that the BufferedReader read all the text, not just a part of it.



As someone asked i add here the remaining part of the code. Please notice that all capital names are constant of various type (int, string etc).
This is the method that is called by the main thread:



public void init()
BufferedWriter bw = null;
List<String> allLines = createRandomStringLines(LINES);
try
String fileName = "SHA1_encode_text.txt";
File logFile = new File(fileName);
System.out.println(logFile.getCanonicalPath());
bw = new BufferedWriter(new FileWriter(logFile));

for(int i = 0; i < allLines.size(); i++)
//write file
String o = sha1FromString(allLines.get(i));
//sha1FromString is a method that change the aspect of the string,
//replacing char by char. Is not important at the moment.
bw.write(o + "n");


catch(Exception e)
e.printStackTrace();
finally
try
bw.close();
catch(Exception e)





The method that create the list of random string is the following. "SYMBOLS" is just a String contains all avaiable chars.



private List<String> createRandomStringLines(int i) 
List<String> list = new ArrayList<String>();
while(i!=0)
StringBuilder builder = new StringBuilder();
int count = 64;
while (count-- != 0)
int character = (int)(Math.random()*SYMBOLS.length());
builder.append(SYMBOLS.charAt(character));

String generatedString = builder.toString();
list.add(generatedString);
i--;

return list;



Note that, the file written is totally correct.










share|improve this question















I read about someone having troubles with BufferedReader: the reader simply do not read the first lines. I have instead the opposite problem. For example, in a text file with 300 lines, it arrives at 200, read it half of it and then the following string is given null, so it stops.



private void readerMethod(File fileList) throws IOException 
BigInteger steps = BigInteger.ZERO;
BufferedReader br = new BufferedReader(new FileReader(fileList));

String st;
//reading file line by line
try
while (true)
st = br.readLine();
if(st == null)
System.out.println("Null string at line " + steps);
break;

System.out.println(steps + " - " + st);
steps = steps.add(BigInteger.ONE);

catch(Exception e)
e.printStackTrace();

finally
try
br.close();
catch(Exception e)




The output of the previous slice of code is as expected until it reaches line 199 (starting from 0). Consider a file with 300 lines.



...
198 - 3B02D5D572B66A82F9D21EE809320DB3E250C6C9
199 - 6E2C69795CB712C27C4097119CE2C5765
Null string at line 200



Notice that, all lines have the same length, so in this output line 199 is not even complete. I checked the file text, and it's correct: it contains all 300 lines and they are all of the same length. Also, in the text there are only capitals letters and numbers, as you can see.



My question is: how can i fix this? I need that the BufferedReader read all the text, not just a part of it.



As someone asked i add here the remaining part of the code. Please notice that all capital names are constant of various type (int, string etc).
This is the method that is called by the main thread:



public void init()
BufferedWriter bw = null;
List<String> allLines = createRandomStringLines(LINES);
try
String fileName = "SHA1_encode_text.txt";
File logFile = new File(fileName);
System.out.println(logFile.getCanonicalPath());
bw = new BufferedWriter(new FileWriter(logFile));

for(int i = 0; i < allLines.size(); i++)
//write file
String o = sha1FromString(allLines.get(i));
//sha1FromString is a method that change the aspect of the string,
//replacing char by char. Is not important at the moment.
bw.write(o + "n");


catch(Exception e)
e.printStackTrace();
finally
try
bw.close();
catch(Exception e)





The method that create the list of random string is the following. "SYMBOLS" is just a String contains all avaiable chars.



private List<String> createRandomStringLines(int i) 
List<String> list = new ArrayList<String>();
while(i!=0)
StringBuilder builder = new StringBuilder();
int count = 64;
while (count-- != 0)
int character = (int)(Math.random()*SYMBOLS.length());
builder.append(SYMBOLS.charAt(character));

String generatedString = builder.toString();
list.add(generatedString);
i--;

return list;



Note that, the file written is totally correct.







java string file bufferedreader reader






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 9 at 9:51

























asked Nov 9 at 9:07









Daniele Buonadonna

408




408







  • 1




    When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
    – Mickael
    Nov 9 at 9:22






  • 2




    Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
    – ygor
    Nov 9 at 9:41







  • 1




    The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
    – Robert Kock
    Nov 9 at 9:55






  • 1




    Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
    – ygor
    Nov 9 at 10:01






  • 1




    BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
    – ygor
    Nov 9 at 10:07












  • 1




    When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
    – Mickael
    Nov 9 at 9:22






  • 2




    Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
    – ygor
    Nov 9 at 9:41







  • 1




    The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
    – Robert Kock
    Nov 9 at 9:55






  • 1




    Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
    – ygor
    Nov 9 at 10:01






  • 1




    BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
    – ygor
    Nov 9 at 10:07







1




1




When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
– Mickael
Nov 9 at 9:22




When you take a look at BufferedReader code, you can see that the size is the number of caracters and not the number of lines. I don't think this is the problem here but you should fix this.
– Mickael
Nov 9 at 9:22




2




2




Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
– ygor
Nov 9 at 9:41





Windows 10 is enough information. Please, show us the code, which generates the file. Do you close the writer properly ? Maybe the written file is not flushed properly before you attempt to read it.
– ygor
Nov 9 at 9:41





1




1




The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
– Robert Kock
Nov 9 at 9:55




The method that reads the file by chance it running together with the method that writes it? Or does the reader start after the writer has finished?
– Robert Kock
Nov 9 at 9:55




1




1




Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
– ygor
Nov 9 at 10:01




Please add "System.out.println("writer closed")" AFTER "bw.close();" and add "System.out.println("reader opening") BEFORE BufferedReader br = new BufferedReader(new FileReader(fileList)); In which order will those two messages appear ?
– ygor
Nov 9 at 10:01




1




1




BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
– ygor
Nov 9 at 10:07




BufferedWriter's default buffer size is 8192. You reader stops reading exactly after 8192 bytes ((40+1)*199 + 33. It is almost certain, that your writer did only flush once.
– ygor
Nov 9 at 10:07












1 Answer
1






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oldest

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up vote
1
down vote













Okay, thanks to the user ygor, i manage to resolve it. The problem was that the BufferReader stars his job when the BufferWriter isn't closed yet. It was sufficient to move the command line that require the reader to work, after the bufferWriter.close() command.






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    Okay, thanks to the user ygor, i manage to resolve it. The problem was that the BufferReader stars his job when the BufferWriter isn't closed yet. It was sufficient to move the command line that require the reader to work, after the bufferWriter.close() command.






    share|improve this answer
























      up vote
      1
      down vote













      Okay, thanks to the user ygor, i manage to resolve it. The problem was that the BufferReader stars his job when the BufferWriter isn't closed yet. It was sufficient to move the command line that require the reader to work, after the bufferWriter.close() command.






      share|improve this answer






















        up vote
        1
        down vote










        up vote
        1
        down vote









        Okay, thanks to the user ygor, i manage to resolve it. The problem was that the BufferReader stars his job when the BufferWriter isn't closed yet. It was sufficient to move the command line that require the reader to work, after the bufferWriter.close() command.






        share|improve this answer












        Okay, thanks to the user ygor, i manage to resolve it. The problem was that the BufferReader stars his job when the BufferWriter isn't closed yet. It was sufficient to move the command line that require the reader to work, after the bufferWriter.close() command.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 9 at 10:54









        Daniele Buonadonna

        408




        408



























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