Convert String in JSON format into CSV / List of Strings

Question

I have created an CSV exporter where I am converting String in JSON format into the Collection of objects and then into the List of strings.

Gson gson = new Gson();   
Type collectionType = new TypeToken<Collection<itemModel>>(){}.getType();
Collection<itemModel> objects = gson.fromJson(jsonString, collectionType);
// jsonString = "[{"name":"A","number":25},{"name":"B","number":26}]"
String filename = "export.csv";
FacesContext fc = FacesContext.getCurrentInstance();
ExternalContext ec = fc.getExternalContext();
ec.responseReset();
ec.setResponseContentType("text/comma-separated-values");
ec.setResponseHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
OutputStream output = ec.getResponseOutputStream();

List<String> strings = new ArrayList<String>();
    for (itemModel obj : objects) {
        strings.add(obj.getName() + ";" + obj.getNumber() +"\n");
    }
    for (String s : strings) {
        output.write(s.getBytes());
    }
fc.responseComplete();

Now, I would like to do the adding of a new string into the List dynamically and replace this row: strings.add(obj.getName() + ";" + obj.getNumber() +"\n"); It should be more robust. Is somehow possible call all getters if I dont know exact names of properties?

Or is better solution how to convert String in JSON format into the List of strings?

Any advice would be appreciated!

Try this link http://stackoverflow.com/questions/8724866/how-to-convert-data-base-records-into-csv-file-in-android. I hope this will help you. — malavika, Apr 15 '14 at 13:02
Thanks for a recommendation but I don't see there a possible solution. I need to call all getters of object class dynamically.. or find another better solution. — PrincAm, Apr 15 '14 at 13:15

Asif Bhutto · Accepted Answer · 2014-04-15T13:22:38.340

0

You need to override toString() method in itemModel Class and build your string according to CSV foramt

@Override
public String toString() {
    StringBuilder builder = new StringBuilder();
    builder.append(name);
    builder.append(";");
    builder.append(number);
    builder.append("\n");
    return builder.toString();
}

// finally wrtie

 List<itemModel> itemModels = gson.fromJson(jsonString, collectionType);
         for (itemModel itemModel : itemModels) {
               output.write(itemModel.toString().getBytes());
        }

edited Apr 15 '14 at 13:22

answered Apr 15 '14 at 13:15

Asif Bhutto

3,916
1
24
21

Absolutely wonderful! It would probably never figured that out. – PrincAm Apr 15 '14 at 13:49

score 0 · Answer 2 · answered Apr 15 '14 at 13:29

0

Implementing toString() of ItemModel is good if you already know all the properties.

You can use Reflection to get all the properties if you already don't know them.

answered Apr 15 '14 at 13:29

Amit P

467
6
20

Thanks for your recommendation! I was trying to implement Reflection but I didn't resolve how to call found getters inside loop `for (itemModel obj : objects) { }` But still toString() is sufficient for me. – PrincAm Apr 16 '14 at 09:18

Convert String in JSON format into CSV / List of Strings

2 Answers2