Create CSV file in Java

Question

I need to create a CSV file in a specific format. Here is the format.

“ROWHEAD”,2016/09/13 03:24:42 -0700,”A”,”BCDE”,002,
“SECHEAD”,2016/09/12 00:00:00 -0700,2016/09/12 23:59:59 -0700,”BCDE”

“COLHEAD”,”Col A”,”Col B”,”Col C”,”Col D”,”Col E”,”Col F”
“SECBODY”,”val A”,”val B”,”val C”,”val D”,”val E”,”val F”
“SECBODY”,”val A”,”val B”,”val C”,”val D”,”val E”,”val F”
“SECBODY”,”val A”,”val B”,”val C”,”val D”,”val E”,”val F”
“SECBODY”,”val A”,”val B”,”val C”,”val D”,”val E”,”val F”

“SECFOOT”,”XXX”,0,0,0,0,”YY”,0,”ZZ”,0,189
“SECCOUNT”,1
"ROWFOOT”,”XXX”,0,0,0,0,”YY”,0,”ZZ”,0,189

I have tried using the normal file writer ways which couldn't help me achieving this. Also I tried openCSV API for the same which even doesn't help much.

How can I create a CSV file with such header and footer values associated in it?

What exact problems did you encounter using Java? Do you have a specific problem with your code? — Tim Biegeleisen
– Tim Biegeleisen, Commented Dec 6, 2016 at 0:40
@Tim -- I could write the CSV file as a normal FileWriter where if the record gets larger it would be hard to handle it. Used OpenCSV but its writing everything as a String, but I have date format as well. — i2ijeya
– i2ijeya, Commented Dec 6, 2016 at 17:42

Jeronimo Backes · Accepted Answer · 2016-12-06 08:08:00Z

Get uniVocity-parsers to handle this. It has an OutputValueSwitch which will match a value in a particular column of each row to determine a RowProcessor to use.

For example, if your input rows are generated from java beans (which it probably does), and some other rows are plain lists of object arrays:

    OutputValueSwitch writerSwitch = new OutputValueSwitch(0); //row identifiers go at column 0

    // If the value is "ROWHEAD", we want to use an BeanWriterProcessor. You can provide field names to be associated with the fields in the class.
    writerSwitch.addSwitchForValue("ROWHEAD", new BeanWriterProcessor(RowHead.class));

    writerSwitch.addSwitchForValue("SECHEAD", new BeanWriterProcessor(SecHead.class));

    // If the value is "SECBODY", a ObjectRowWriterProcessor will be used. Let's assume you are writing object arrays here
    writerSwitch.addSwitchForValue("SECBODY", new ObjectRowWriterProcessor()); 
    //...and so on.

    //Configure the CSV writer here
    CsvWriterSettings settings = new CsvWriterSettings();
    // the writer should use the switch defined above
    settings.setRowWriterProcessor(writerSwitch);

    settings.getFormat().setLineSeparator("\n");
    settings.setHeaderWritingEnabled(false);
    //etc

    //Create the CSV writer
    CsvWriter writer = new CsvWriter(new File("/path/to/your.csv"), "UTF-8", settings);

    writer.processRecord(new RowHead()); //writing bean
    writer.processRecord(new SecHead()); //writing the other bean
    writer.processRecord(new Object[]{"SECBODY", "Value 1", "Value 2", "etc"}); //writing an array

    writer.close();

You can also use maps as input rows. For fully working examples, refer to this and this

You can do anything with this library and I hope it helps you.

Disclosure: I am the author of this library. It's open-source and free (Apache V2.0 license).

Thanks @Jeronimo. I shall try this. Hope this satisfies my need.

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