JSON Array conversion to CSV - json

Question

I want to convert JSON to CSV. I am using the list function to meet the purpose.
But I am not getting desirable output for JSON array. Please find the sample JSON and list function which I am using:
Sample JSON document:
{
"NAME": "Viv",
"EMAIL": "lo",
"PUBLIC_OFFICIALS_CONTACTED": [{
"NAME_PUBLIC_OFFICIAL": [ "ff"],
"TITLE_PUBLIC_OFFICIAL": ["ff"]
}]
,
"COMMUNICATION_TYPE": ["Meeting","Phone","Handout","Conference"],
"NAMES_OF_OTHERS_FROM_XXX": [{
"NAME_OF_OTHERS": ["ff"],
"TITLE_OF_OTHERS": [ "ff"]
}]
,
"COMMUNICATION_BENEFIT": "Yes",
"AFFILIATE_NAME": "name",
"COMMUNICATION_ARRANGED": "Yes, arranged by you"
}
and list function which I am using is:
function(head, req) {
var row,
first = true;
// output HTTP headers
start({
headers: {
'Content-Type': 'text/csv'
}
,
});
// iterate through the result set
while(row = getRow()) {
// get the doc (include_docs=true)
var doc = row.doc;
// if this is the first row
if (first) {
// output column headers
send(Object.keys(doc).join(',') + 'n');
first = false;
}
// build up a line of output
var line = '';
// iterate through each row
for(var i in doc) {
// comma separator
if (line.length > 0) {
line += ',';
}
// output the value, ensuring values that themselves
// contain commas are enclosed in double quotes
var val = doc[i];
if (typeof val == 'string' && val.indexOf(',') > -1) {
line += '"' + val.replace(/"/g,'""') + '"';
}
else {
line += val;
}
}
line += 'n';
// send the line
send(line);
}
};
Please find attached the CSV output and expected output exported in excel.
Also, there is an issue in saving checkbox values. Please help me in writing the list function for the above JSON conversion to CSV.
current output:
expected output:

Answer 1

CSV is a single, flat list of values in each row, and one row of headers. The expected output shared in this question isn't compatible with CSV - it will be necessary to "flatten" your JSON by unpacking the nested data structures and making them instead into a flat hierarchy of data that can then become CSV. Try searching for "JSON to CSV" with a search engine for some examples - hope that helps!

Answer 2

I have refered this gitHUb link and tried the following:
JsonFlattener.class : Which will read the json string & extract the key & value
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.*;
public class JsonFlattener {
public Map<String, String> parse(JSONObject jsonObject) throws JSONException {
Map<String, String> flatJson = new HashMap<String, String>();
flatten(jsonObject, flatJson, "");
return flatJson;
}
public List<Map<String, String>> parse(JSONArray jsonArray) throws JSONException {
List<Map<String, String>> flatJson = new ArrayList<Map<String, String>>();
int length = jsonArray.length();
for (int i = 0; i < length; i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Map<String, String> stringMap = parse(jsonObject);
flatJson.add(stringMap);
}
return flatJson;
}
public List<Map<String, String>> parseJson(String json) throws Exception {
List<Map<String, String>> flatJson = null;
try {
JSONObject jsonObject = new JSONObject(json);
flatJson = new ArrayList<Map<String, String>>();
flatJson.add(parse(jsonObject));
} catch (JSONException je) {
flatJson = handleAsArray(json);
}
return flatJson;
}
private List<Map<String, String>> handleAsArray(String json) throws Exception {
List<Map<String, String>> flatJson = null;
try {
JSONArray jsonArray = new JSONArray(json);
flatJson = parse(jsonArray);
} catch (Exception e) {
throw new Exception("Json might be malformed");
}
return flatJson;
}
private void flatten(JSONArray obj, Map<String, String> flatJson, String prefix) throws JSONException {
int length = obj.length();
for (int i = 0; i < length; i++) {
if (obj.get(i).getClass() == JSONArray.class) {
JSONArray jsonArray = (JSONArray) obj.get(i);
if (jsonArray.length() < 1) continue;
flatten(jsonArray, flatJson, prefix + i);
} else if (obj.get(i).getClass() == JSONObject.class) {
JSONObject jsonObject = (JSONObject) obj.get(i);
flatten(jsonObject, flatJson, prefix + (i + 1));
} else {
String value = obj.getString(i);
if (value != null)
flatJson.put(prefix + (i + 1), value);
}
}
}
private void flatten(JSONObject obj, Map<String, String> flatJson, String prefix) throws JSONException {
Iterator iterator = obj.keys();
while (iterator.hasNext()) {
String key = iterator.next().toString();
if (obj.get(key).getClass() == JSONObject.class) {
JSONObject jsonObject = (JSONObject) obj.get(key);
flatten(jsonObject, flatJson, prefix);
} else if (obj.get(key).getClass() == JSONArray.class) {
JSONArray jsonArray = (JSONArray) obj.get(key);
if (jsonArray.length() < 1) continue;
flatten(jsonArray, flatJson, key);
} else {
String value = obj.getString(key);
if (value != null && !value.equals("null"))
flatJson.put(prefix + key, value);
}
}
}
}
CSVWriter.class:Which transform the json string to CSV file
import org.apache.commons.lang.StringUtils;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;
public class CSVWriter {
public void writeAsCSV(List<Map<String, String>> flatJson, String fileName) throws FileNotFoundException {
Set<String> headers = collectHeaders(flatJson);
String output = StringUtils.join(headers.toArray(), ",") + "\n";
for (Map<String, String> map : flatJson) {
output = output + getCommaSeperatedRow(headers, map) + "\n";
}
writeToFile(output, fileName);
}
private void writeToFile(String output, String fileName) throws FileNotFoundException {
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(fileName));
writer.write(output);
} catch (IOException e) {
e.printStackTrace();
} finally {
close(writer);
}
}
private void close(BufferedWriter writer) {
try {
if (writer != null) {
writer.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
private String getCommaSeperatedRow(Set<String> headers, Map<String, String> map) {
List<String> items = new ArrayList<String>();
for (String header : headers) {
String value = map.get(header) == null ? "" : map.get(header).replace(",", "");
items.add(value);
}
return StringUtils.join(items.toArray(), ",");
}
private Set<String> collectHeaders(List<Map<String, String>> flatJson) {
Set<String> headers = new TreeSet<String>();
for (Map<String, String> map : flatJson) {
headers.addAll(map.keySet());
}
return headers;
}
}
JSONtoCSV.class : which will use the above class to parse the json & write the key values as a .csv file
import java.util.List;
import java.util.Map;
public class JSONtoCSV {
public static void main(String[] args) throws Exception {
String jsonString = "{\n" +
"\"NAME\": \"Viv\",\n" +
"\"EMAIL\": \"lo\",\n" +
"\n" +
"\"PUBLIC_OFFICIALS_CONTACTED\": [{\"NAME_PUBLIC_OFFICIAL\": [ \"ff\"],\n" +
"\"TITLE_PUBLIC_OFFICIAL\": [\"ff\"]}],\n" +
"\n" +
"\"COMMUNICATION_TYPE\": [\"Meeting\",\"Phone\",\"Handout\",\"Conference\"],\n" +
"\n" +
"\"NAMES_OF_OTHERS_FROM_XXX\": [{\"NAME_OF_OTHERS\": [\"ff\"],\n" +
"\"TITLE_OF_OTHERS\": [ \"ff\"]}],\n" +
"\n" +
"\"COMMUNICATION_BENEFIT\": \"Yes\",\n" +
"\"AFFILIATE_NAME\": \"name\",\n" +
"\"COMMUNICATION_ARRANGED\": \"Yes, arranged by you\"\n" +
"}";
JsonFlattener parser = new JsonFlattener();
CSVWriter writer = new CSVWriter();
List<Map<String, String>> flatJson = parser.parseJson(jsonString);
writer.writeAsCSV(flatJson, "C:/sample.csv");
}
}