Convert CSV to JSON JSON payload should be included in square brackets

Question

Hi Experts

I have a requirement to convert CSV to JSON. Assume if CSV files have got 2 rows. I need to create a JSON file for each row. This means output will be 2 json files.

Sample Test data: Test.csv

ID,fileName,Type,Direction,Date
1001,File1,PDF,Out,20180518
1002,File2,DOC,Out,20180502
 

I have written below code for achieving this. The code is working fine and creating individual JSON files for each row as:

File1.txt

{
  "ID" : "1001",
  "fileName" : "File1",
  "Type" : "PDF",
  "Direction" : "Out",
  "Date" : "20180518"
}

File2.txt

{
  "ID" : "1002",
  "fileName" : "File2",
  "Type" : "DOC",
  "Direction" : "Out",
  "Date" : "20180502"
}

I need to include the JSON payload in square brackets as root. E.g. Output should be as below. How can I achieve this

File1.txt

[

{
  "ID" : "1002",
  "fileName" : "File2",
  "Type" : "DOC",
  "Direction" : "Out",
  "Date" : "20180502"
}

]

File2.txt

[

{
  "ID" : "1002",
  "fileName" : "File2",
  "Type" : "DOC",
  "Direction" : "Out",
  "Date" : "20180502"
}

]

Code:

package com.sap.csv2json;

import java.io.File;

import java.util.List;

import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.SerializationFeature;

import com.fasterxml.jackson.dataformat.csv.CsvMapper;

import com.fasterxml.jackson.dataformat.csv.CsvSchema;

public class ConvertCSVtoJson {

@SuppressWarnings("unchecked")

public static void main(String[] args) throws Exception {

        File input = new File("C:\\Users\\akellap\\RND\\JSON\\Source\\Test.csv");

        CsvSchema csvSchema = CsvSchema.builder().setUseHeader(true).build();

        CsvMapper csvMapper = new CsvMapper();

        // Read data from CSV file

        List<Object> readAll = csvMapper.readerFor(Map.class).with(csvSchema).readValues(input).readAll();

                    ObjectMapper mapper = new ObjectMapper();

        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        // Write JSON formated data to output.json file

           for (Object row : readAll) {

        Map<String, String> map = (Map<String, String>) row;

        String fileName = map.get("fileName");

        File output = new File("C:\\Users\\akellap\\RND\\JSON\\Target\\"+fileName+".txt");

         mapper.writerWithDefaultPrettyPrinter().writeValue(output, row);

                }

          }

}

Comments

which jar files are requird to execute above code

---

Hey, @Ramakrishna,

Could you please tell me why you need jar files? I mean are you getting any error using this code?

Answer 1

The JSON payload uses a list and so to have square brackets in your output file, you need to convert the data of arrays into list using the following code:

Arrays.asList(arrayofdata);

So the complete code should look like this:

package com.sap.csv2json;

import java.io.File;

import java.util.List;

import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.databind.SerializationFeature;

import com.fasterxml.jackson.dataformat.csv.CsvMapper;

import com.fasterxml.jackson.dataformat.csv.CsvSchema;


public class ConvertCSVtoJson {

@SuppressWarnings("unchecked")

public static void main(String[] args) throws Exception {

        File input = new File("C:\\Users\\akellap\\RND\\JSON\\Source\\Test.csv");

        CsvSchema csvSchema = CsvSchema.builder().setUseHeader(true).build();

        CsvMapper csvMapper = new CsvMapper();

        // Read data from CSV file

        List<Object> readAll = Arrays.asList(csvMapper.readerFor(Map.class).with(csvSchema).readValues(input).readAll());

                    ObjectMapper mapper = new ObjectMapper();

        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        // Write JSON formated data to output.json file

           for (Object row : readAll) {

        Map<String, String> map = (Map<String, String>) row;

        String fileName = map.get("fileName");

        File output = new File("C:\\Users\\akellap\\RND\\JSON\\Target\\"+fileName+".txt");

         mapper.writerWithDefaultPrettyPrinter().writeValue(output, row);

                }

          }

}

And the output file will be as follows:

 

Comments

csvMapper.readerFor() is giving the error

---

Hey, @Ram, 

You can go through this https://www.edureka.co/community/61291/getting-below-error-method-readerfor-undefined-csvmapper. I hope this will be helpful. If not them let me know.