Mixing
Flink Data Stream CSV Writer not writing data to CSV file
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I am new to apache flink and trying to learn data streams. I am reading student data which has 3 columns(Name,Subject and Marks) from a csv file. I have applied filter on marks and only selecting those records where marks >40.
I am trying to write this data to csv file but program runs successfully and csv file remains empty. No data gets written to csv file.
I tried with different syntax for writing csv file but none of them worked for me. I am running this locally through eclipse. Write to text file works fine.
DataStream<String> text = env.readFile(format, params.get("input"),
FileProcessingMode.PROCESS_CONTINUOUSLY,100);
DataStream<String> filtered = text.filter(new FilterFunction<String>(){
public boolean filter(String value) {
String tokens = value.split(",");
return Integer.parseInt(tokens[2]) >= 40;
}
});
filtered.writeAsText("testFilter",WriteMode.OVERWRITE);
DataStream<Tuple2<String, Integer>> tokenized = filtered
.map(new MapFunction<String, Tuple2<String, Integer>>(){
public Tuple2<String, Integer> map(String value) throws Exception {
return new Tuple2("Test", Integer.valueOf(1));
}
});
tokenized.print();
tokenized.writeAsCsv("file:///home/Test/Desktop/output.csv",
WriteMode.OVERWRITE, "/n", ",");
try {
env.execute();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
Below is my input CSV format:
Name1,Subj1,30
Name1,Subj2,40
Name1,Subj3,40
Name1,Subj4,40
Tokenized.print() prints all correct records.
csv apache-flink
edited Jan 3 at 7:36
Stedy
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
add a comment |
I am new to apache flink and trying to learn data streams. I am reading student data which has 3 columns(Name,Subject and Marks) from a csv file. I have applied filter on marks and only selecting those records where marks >40.
I am trying to write this data to csv file but program runs successfully and csv file remains empty. No data gets written to csv file.
I tried with different syntax for writing csv file but none of them worked for me. I am running this locally through eclipse. Write to text file works fine.
DataStream<String> text = env.readFile(format, params.get("input"),
FileProcessingMode.PROCESS_CONTINUOUSLY,100);
DataStream<String> filtered = text.filter(new FilterFunction<String>(){
public boolean filter(String value) {
String tokens = value.split(",");
return Integer.parseInt(tokens[2]) >= 40;
}
});
filtered.writeAsText("testFilter",WriteMode.OVERWRITE);
DataStream<Tuple2<String, Integer>> tokenized = filtered
.map(new MapFunction<String, Tuple2<String, Integer>>(){
public Tuple2<String, Integer> map(String value) throws Exception {
return new Tuple2("Test", Integer.valueOf(1));
}
});
tokenized.print();
tokenized.writeAsCsv("file:///home/Test/Desktop/output.csv",
WriteMode.OVERWRITE, "/n", ",");
try {
env.execute();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
Below is my input CSV format:
Name1,Subj1,30
Name1,Subj2,40
Name1,Subj3,40
Name1,Subj4,40
Tokenized.print() prints all correct records.
csv apache-flink
edited Jan 3 at 7:36
Stedy
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
add a comment |
I am new to apache flink and trying to learn data streams. I am reading student data which has 3 columns(Name,Subject and Marks) from a csv file. I have applied filter on marks and only selecting those records where marks >40.
I am trying to write this data to csv file but program runs successfully and csv file remains empty. No data gets written to csv file.
I tried with different syntax for writing csv file but none of them worked for me. I am running this locally through eclipse. Write to text file works fine.
DataStream<String> text = env.readFile(format, params.get("input"),
FileProcessingMode.PROCESS_CONTINUOUSLY,100);
DataStream<String> filtered = text.filter(new FilterFunction<String>(){
public boolean filter(String value) {
String tokens = value.split(",");
return Integer.parseInt(tokens[2]) >= 40;
}
});
filtered.writeAsText("testFilter",WriteMode.OVERWRITE);
DataStream<Tuple2<String, Integer>> tokenized = filtered
.map(new MapFunction<String, Tuple2<String, Integer>>(){
public Tuple2<String, Integer> map(String value) throws Exception {
return new Tuple2("Test", Integer.valueOf(1));
}
});
tokenized.print();
tokenized.writeAsCsv("file:///home/Test/Desktop/output.csv",
WriteMode.OVERWRITE, "/n", ",");
try {
env.execute();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
Below is my input CSV format:
Name1,Subj1,30
Name1,Subj2,40
Name1,Subj3,40
Name1,Subj4,40
Tokenized.print() prints all correct records.
csv apache-flink
edited Jan 3 at 7:36
Stedy
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
I am new to apache flink and trying to learn data streams. I am reading student data which has 3 columns(Name,Subject and Marks) from a csv file. I have applied filter on marks and only selecting those records where marks >40.
I am trying to write this data to csv file but program runs successfully and csv file remains empty. No data gets written to csv file.
I tried with different syntax for writing csv file but none of them worked for me. I am running this locally through eclipse. Write to text file works fine.
DataStream<String> text = env.readFile(format, params.get("input"),
FileProcessingMode.PROCESS_CONTINUOUSLY,100);
DataStream<String> filtered = text.filter(new FilterFunction<String>(){
public boolean filter(String value) {
String tokens = value.split(",");
return Integer.parseInt(tokens[2]) >= 40;
}
});
filtered.writeAsText("testFilter",WriteMode.OVERWRITE);
DataStream<Tuple2<String, Integer>> tokenized = filtered
.map(new MapFunction<String, Tuple2<String, Integer>>(){
public Tuple2<String, Integer> map(String value) throws Exception {
return new Tuple2("Test", Integer.valueOf(1));
}
});
tokenized.print();
tokenized.writeAsCsv("file:///home/Test/Desktop/output.csv",
WriteMode.OVERWRITE, "/n", ",");
try {
env.execute();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
Below is my input CSV format:
Name1,Subj1,30
Name1,Subj2,40
Name1,Subj3,40
Name1,Subj4,40
Tokenized.print() prints all correct records.
csv apache-flink
csv apache-flink
edited Jan 3 at 7:36
Stedy
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
edited Jan 3 at 7:36
Stedy
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
edited Jan 3 at 7:36
Stedy
5,347144969
edited Jan 3 at 7:36
Stedy
5,347144969
edited Jan 3 at 7:36
Stedy
5,347144969
5,347144969
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
asked Jan 3 at 7:16
Omkar SabaneOmkar Sabane
1
1
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
I did a little experimenting, and found that this job works just fine:
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class WriteCSV {
public static void main(String args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
env.fromElements(new Tuple2<>("abc", 1), new Tuple2<>("def", 2))
.writeAsCsv("file:///tmp/test.csv", FileSystem.WriteMode.OVERWRITE, "n", ",");
env.execute();
}
}
If I don't set the parallelism to 1, then the results are different. In that case, test.csv is a directory containing four files, each written by one of the four parallel subtasks.
I'm not sure what's wrong in your case, but maybe you can work backwards from this example (assuming it works for you).
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
add a comment |
You should remove tokenized.print(); before tokenized.writeAsCsv();.
It will consume the data the print();.
edited Feb 20 at 18:08
double-beep
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
I did a little experimenting, and found that this job works just fine:
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class WriteCSV {
public static void main(String args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
env.fromElements(new Tuple2<>("abc", 1), new Tuple2<>("def", 2))
.writeAsCsv("file:///tmp/test.csv", FileSystem.WriteMode.OVERWRITE, "n", ",");
env.execute();
}
}
If I don't set the parallelism to 1, then the results are different. In that case, test.csv is a directory containing four files, each written by one of the four parallel subtasks.
I'm not sure what's wrong in your case, but maybe you can work backwards from this example (assuming it works for you).
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
add a comment |
I did a little experimenting, and found that this job works just fine:
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class WriteCSV {
public static void main(String args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
env.fromElements(new Tuple2<>("abc", 1), new Tuple2<>("def", 2))
.writeAsCsv("file:///tmp/test.csv", FileSystem.WriteMode.OVERWRITE, "n", ",");
env.execute();
}
}
If I don't set the parallelism to 1, then the results are different. In that case, test.csv is a directory containing four files, each written by one of the four parallel subtasks.
I'm not sure what's wrong in your case, but maybe you can work backwards from this example (assuming it works for you).
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
add a comment |
I did a little experimenting, and found that this job works just fine:
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class WriteCSV {
public static void main(String args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
env.fromElements(new Tuple2<>("abc", 1), new Tuple2<>("def", 2))
.writeAsCsv("file:///tmp/test.csv", FileSystem.WriteMode.OVERWRITE, "n", ",");
env.execute();
}
}
If I don't set the parallelism to 1, then the results are different. In that case, test.csv is a directory containing four files, each written by one of the four parallel subtasks.
I'm not sure what's wrong in your case, but maybe you can work backwards from this example (assuming it works for you).
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
I did a little experimenting, and found that this job works just fine:
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.core.fs.FileSystem;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
public class WriteCSV {
public static void main(String args) throws Exception {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
env.setParallelism(1);
env.fromElements(new Tuple2<>("abc", 1), new Tuple2<>("def", 2))
.writeAsCsv("file:///tmp/test.csv", FileSystem.WriteMode.OVERWRITE, "n", ",");
env.execute();
}
}
If I don't set the parallelism to 1, then the results are different. In that case, test.csv is a directory containing four files, each written by one of the four parallel subtasks.
I'm not sure what's wrong in your case, but maybe you can work backwards from this example (assuming it works for you).
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
answered Jan 3 at 8:13
David AndersonDavid Anderson
6,71821424
6,71821424
add a comment |
add a comment |
You should remove tokenized.print(); before tokenized.writeAsCsv();.
It will consume the data the print();.
edited Feb 20 at 18:08
double-beep
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
add a comment |
You should remove tokenized.print(); before tokenized.writeAsCsv();.
It will consume the data the print();.
edited Feb 20 at 18:08
double-beep
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
add a comment |
You should remove tokenized.print(); before tokenized.writeAsCsv();.
It will consume the data the print();.
edited Feb 20 at 18:08
double-beep
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
You should remove tokenized.print(); before tokenized.writeAsCsv();.
It will consume the data the print();.
edited Feb 20 at 18:08
double-beep
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
edited Feb 20 at 18:08
double-beep
3,10641432
edited Feb 20 at 18:08
double-beep
3,10641432
edited Feb 20 at 18:08
double-beep
3,10641432
3,10641432
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
answered Feb 20 at 17:43
Aakarsh GuptaAakarsh Gupta
415
415
add a comment |
add a comment |
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