Split csv file without getting incomplete lines
I have successfully split a csv but it sometimes has some file chunks with incomplete last lines. The file is wrapped using a RandomAccessFile object. Here is my code:
long sourceSize = raf.length();
long bytesPerSplit = sourceSize / splits;
long remainingBytes = sourceSize % splits;
int maxReadBufferSize = 8 * 1024; // 8 KB
for (int destIx = 1; destIx <= splits; destIx++) {
// TODO: change so that first name is the year involved
try(BufferedOutputStream bw = new BufferedOutputStream(
new FileOutputStream(destination + "\chunk" + destIx + ".csv"))) {
if (bytesPerSplit > maxReadBufferSize) {
long numReads = bytesPerSplit / maxReadBufferSize;
long numRemainingRead = bytesPerSplit % maxReadBufferSize;
for (int i = 0; i < numReads; i++) {
readWrite(raf, bw, maxReadBufferSize);
}
if (numRemainingRead > 0) readWrite(raf, bw, numRemainingRead);
} else readWrite(raf, bw, bytesPerSplit);
}
I thought of checking if the last byte array read would have a newline at the end beforehand and if not increasing the buffer size to be read but I don't know if it's possible to do that with a RandomAccessFile object
java
asked Nov 12 '18 at 4:00
Levi
186
add a comment |
I have successfully split a csv but it sometimes has some file chunks with incomplete last lines. The file is wrapped using a RandomAccessFile object. Here is my code:
long sourceSize = raf.length();
long bytesPerSplit = sourceSize / splits;
long remainingBytes = sourceSize % splits;
int maxReadBufferSize = 8 * 1024; // 8 KB
for (int destIx = 1; destIx <= splits; destIx++) {
// TODO: change so that first name is the year involved
try(BufferedOutputStream bw = new BufferedOutputStream(
new FileOutputStream(destination + "\chunk" + destIx + ".csv"))) {
if (bytesPerSplit > maxReadBufferSize) {
long numReads = bytesPerSplit / maxReadBufferSize;
long numRemainingRead = bytesPerSplit % maxReadBufferSize;
for (int i = 0; i < numReads; i++) {
readWrite(raf, bw, maxReadBufferSize);
}
if (numRemainingRead > 0) readWrite(raf, bw, numRemainingRead);
} else readWrite(raf, bw, bytesPerSplit);
}
I thought of checking if the last byte array read would have a newline at the end beforehand and if not increasing the buffer size to be read but I don't know if it's possible to do that with a RandomAccessFile object
java
asked Nov 12 '18 at 4:00
Levi
186
Are you.flush()ing and.close()ing the output stream?
– NRitH
Nov 12 '18 at 4:23
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35
add a comment |
I have successfully split a csv but it sometimes has some file chunks with incomplete last lines. The file is wrapped using a RandomAccessFile object. Here is my code:
long sourceSize = raf.length();
long bytesPerSplit = sourceSize / splits;
long remainingBytes = sourceSize % splits;
int maxReadBufferSize = 8 * 1024; // 8 KB
for (int destIx = 1; destIx <= splits; destIx++) {
// TODO: change so that first name is the year involved
try(BufferedOutputStream bw = new BufferedOutputStream(
new FileOutputStream(destination + "\chunk" + destIx + ".csv"))) {
if (bytesPerSplit > maxReadBufferSize) {
long numReads = bytesPerSplit / maxReadBufferSize;
long numRemainingRead = bytesPerSplit % maxReadBufferSize;
for (int i = 0; i < numReads; i++) {
readWrite(raf, bw, maxReadBufferSize);
}
if (numRemainingRead > 0) readWrite(raf, bw, numRemainingRead);
} else readWrite(raf, bw, bytesPerSplit);
}
I thought of checking if the last byte array read would have a newline at the end beforehand and if not increasing the buffer size to be read but I don't know if it's possible to do that with a RandomAccessFile object
java
asked Nov 12 '18 at 4:00
Levi
186
I have successfully split a csv but it sometimes has some file chunks with incomplete last lines. The file is wrapped using a RandomAccessFile object. Here is my code:
long sourceSize = raf.length();
long bytesPerSplit = sourceSize / splits;
long remainingBytes = sourceSize % splits;
int maxReadBufferSize = 8 * 1024; // 8 KB
for (int destIx = 1; destIx <= splits; destIx++) {
// TODO: change so that first name is the year involved
try(BufferedOutputStream bw = new BufferedOutputStream(
new FileOutputStream(destination + "\chunk" + destIx + ".csv"))) {
if (bytesPerSplit > maxReadBufferSize) {
long numReads = bytesPerSplit / maxReadBufferSize;
long numRemainingRead = bytesPerSplit % maxReadBufferSize;
for (int i = 0; i < numReads; i++) {
readWrite(raf, bw, maxReadBufferSize);
}
if (numRemainingRead > 0) readWrite(raf, bw, numRemainingRead);
} else readWrite(raf, bw, bytesPerSplit);
}
I thought of checking if the last byte array read would have a newline at the end beforehand and if not increasing the buffer size to be read but I don't know if it's possible to do that with a RandomAccessFile object
java
java
asked Nov 12 '18 at 4:00
Levi
186
asked Nov 12 '18 at 4:00
Levi
186
asked Nov 12 '18 at 4:00
Levi
186
asked Nov 12 '18 at 4:00
Levi
186
asked Nov 12 '18 at 4:00
Levi
186
186
Are you.flush()ing and.close()ing the output stream?
– NRitH
Nov 12 '18 at 4:23
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35
add a comment |
Are you.flush()ing and.close()ing the output stream?
– NRitH
Nov 12 '18 at 4:23
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35
Are you
.flush()ing and .close()ing the output stream?– NRitH
Nov 12 '18 at 4:23
Are you
.flush()ing and .close()ing the output stream?– NRitH
Nov 12 '18 at 4:23
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35
add a comment |
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Are you
.flush()ing and.close()ing the output stream?– NRitH
Nov 12 '18 at 4:23
It's in a try-with-resources block
– Levi
Nov 12 '18 at 13:35