Java structure for Datatables editor json

Question

I need a Java data structure for some JSON data passed to me by the Datatables Editor. The format of the data received is this:

{
    "action":"edit",
    "data": {
        "1009558":{
            "weekNumber":"2"
            ... (more properties)
         }
     }
}

Here's the full documentation: https://editor.datatables.net/manual/server

Edit: The documentation shows the data sent as form params. I am stringifying the data and sending it as JSON. An example is above.

"1009558" is the row ID. If there are multiple rows sent by the editor, there would be multiple array entries (each with an ID).

Can anyone offer some advice on how to make a Java data structure for deserialization (by Spring MVC)? I can map "action" easy enough, but I'm getting stuck on the "data" element.

Answer 1

I'm a huge fan of Joe Littlejohn's JSON tool . Provide it with a sample JSON file and it can generate POJOs for you.

Here's a sample of what it generated, based on a snipped of JSON from the site you posted.

JSON:

{
"data": [
    {
        "DT_RowId":   "row_29",
        "first_name": "Fiona",
        "last_name":  "Green",
        "position":   "Chief Operating Officer (COO)",
        "office":     "San Francisco",
        "extn":       "2947",
        "salary":     "850000",
        "start_date": "2010-03-11"
    }
]

}

JAVA:

@Generated("org.jsonschema2pojo")
public class Datum {

    public String dTRowId;
    public String firstName;
    public String lastName;
    public String position;
    public String office;
    public String extn;
    public String salary;
    public String startDate;
}

@Generated("org.jsonschema2pojo")
public class Example {
    public List<Datum> data = new ArrayList<Datum>();
}

Update:

It looks like this is what the form submit actually sends:

action:edit
data[row_1][first_name]:Tiger23
data[row_1][last_name]:Nixon
data[row_1][position]:System Architect
data[row_1][office]:Edinburgh
data[row_1][extn]:5421
data[row_1][start_date]:2011-04-25
data[row_1][salary]:320800

I don't think this is Json, and I dunno if I would try to treat it as such. If you need to submit form data with Java, you might be better of using the Apache HttpComponents . You can reuse the Java "data" object above as a domain object, and then populate the POST content with Strings of the format:

data[ \DT_RowId\ ][\PropertyName\]: \PropertyValue\

Answer 2

I'd rather suggest you to use jackson .

Here's an example, that you're asking for:

package com.github.xsavikx.jackson;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.util.HashMap;
import java.util.Map;

public class JacksonTest {
    public static void main(String[] args) throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        Map<String, DatabaseRow> data = new HashMap<>();
        DatabaseRow row = new DatabaseRow(2, "someData");
        data.put("1009558", row);
        String action = "action";
        DatabaseEntry dbEntry = new DatabaseEntry();
        dbEntry.setAction(action);
        dbEntry.setData(data);
        System.out.println(objectMapper.writeValueAsString(dbEntry));
    }
}

And the result:

{"action":"action","data":{"1009558":{"weekNumber":2,"someData":"someData"}}}

Models:

package com.github.xsavikx.jackson;

import java.util.Map;

public class DatabaseEntry {
    private String action;
    private Map<String, DatabaseRow> data;

    public DatabaseEntry() {

    }

    public DatabaseEntry(String action, Map<String, DatabaseRow> data) {
        this.action = action;
        this.data = data;
    }

    public Map<String, DatabaseRow> getData() {

        return data;
    }

    public void setData(Map<String, DatabaseRow> data) {
        this.data = data;
    }

    public String getAction() {
        return action;
    }

    public void setAction(String action) {
        this.action = action;
    }
}

package com.github.xsavikx.jackson;

public class DatabaseRow {
    private int weekNumber;
    private String someData;
    public DatabaseRow(){
    }
    public DatabaseRow(int weekNumber, String someData) {
        this.weekNumber = weekNumber;
        this.someData = someData;
    }

    public int getWeekNumber() {
        return weekNumber;
    }

    public void setWeekNumber(int weekNumber) {
        this.weekNumber = weekNumber;
    }

    public String getSomeData() {
        return someData;
    }

    public void setSomeData(String someData) {
        this.someData = someData;
    }
}

Update: more generic solution with Map of maps:

package com.github.xsavikx.jackson;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class JacksonTest {
    public static void main(String[] args) throws IOException {
        serializeTest();
        deserializeTest();
    }
    private static void deserializeTest() throws IOException {
        ObjectMapper objectMapper = new ObjectMapper();
        DatabaseEntry databaseEntry = objectMapper.readValue("{\"action\":\"action\",\"data\":{\"1009558\":{\"weekNumber\":2,\"someData\":\"someData\"}}}", DatabaseEntry.class);
        System.out.println(databaseEntry);
    }

    private static void serializeTest() throws JsonProcessingException {
        ObjectMapper objectMapper = new ObjectMapper();
        Map<String,Map<String,String>> data = new HashMap<>();
        Map<String,String> values = new HashMap<>();
        values.put("weekDay","2");
        values.put("unpredictableValue","value");
        data.put("1009558", values);
        String action = "action";
        DatabaseEntry dbEntry = new DatabaseEntry();
        dbEntry.setAction(action);
        dbEntry.setData(data);
        System.out.println(objectMapper.writeValueAsString(dbEntry));
    }
}

Model: package com.github.xsavikx.jackson;

import java.util.Map;

public class DatabaseEntry {
    private String action;
    private Map<String, Map<String,String>> data;

    public DatabaseEntry() {

    }

    public String getAction() {
        return action;
    }

    public void setAction(String action) {
        this.action = action;
    }

    public Map<String, Map<String, String>> getData() {
        return data;
    }

    public void setData(Map<String, Map<String, String>> data) {
        this.data = data;
    }
}

Answer 3

With Spring Boot the json conversion between server and client is automatic ( https://stackoverflow.com/a/44842806/3793165 ).

This way is working for me:

Controller

@PostMapping(value="/nuevoVideo")
    @ResponseBody
    public RespuestaCreateVideo crearNuevoVideo(@RequestBody PeticionVideos datos) {
       RespuestaCreateVideo respuesta = new RespuestaCreateVideo();
       respuesta.setData("datos");
       //respuesta.setError("error"); // implement the logic for error and return the message to show to the user.
      return respuesta;
    }

where PeticionVideos (RequestVideos) is the create structure Datatables editor sends (with setters, getters...):

public class PeticionVideos {
    private Map<String, Video> data;
    private String action;
}

The response from the server to the client datatable is waiting for has a particular format (check at https://editor.datatables.net/manual/server ).

I often use this:

public class RespuestaCreateVideo { //ResponseCreateVideo
    private String data;
    private String error;
}

After two days trying this is working perfect now!