Convert a JSON String to a HashMap

Question

I wrote this code some days back by recursion.

public static Map<String, Object> jsonToMap(JSONObject json) throws JSONException {
    Map<String, Object> retMap = new HashMap<String, Object>();
    
    if(json != JSONObject.NULL) {
        retMap = toMap(json);
    }
    return retMap;
}

public static Map<String, Object> toMap(JSONObject object) throws JSONException {
    Map<String, Object> map = new HashMap<String, Object>();

    Iterator<String> keysItr = object.keys();
    while(keysItr.hasNext()) {
        String key = keysItr.next();
        Object value = object.get(key);
        
        if(value instanceof JSONArray) {
            value = toList((JSONArray) value);
        }
        
        else if(value instanceof JSONObject) {
            value = toMap((JSONObject) value);
        }
        map.put(key, value);
    }
    return map;
}

public static List<Object> toList(JSONArray array) throws JSONException {
    List<Object> list = new ArrayList<Object>();
    for(int i = 0; i < array.length(); i++) {
        Object value = array.get(i);
        if(value instanceof JSONArray) {
            value = toList((JSONArray) value);
        }

        else if(value instanceof JSONObject) {
            value = toMap((JSONObject) value);
        }
        list.add(value);
    }
    return list;
}

Using Jackson library:

import com.fasterxml.jackson.databind.ObjectMapper;

TypeReference<HashMap<String, Object>> typeRef = new TypeReference<>() {};
Map<String, Object> mapping = new ObjectMapper().readValue(jsonStr, typeRef);

Using Gson, you can do the following:

Map<String, Object> retMap = new Gson().fromJson(
    jsonString, new TypeToken<HashMap<String, Object>>() {}.getType()
);

Hope this will work, try this:

import com.fasterxml.jackson.databind.ObjectMapper;
Map<String, Object> response = new ObjectMapper().readValue(str, HashMap.class);

str, your JSON String

As Simple as this, if you want emailid,

String emailIds = response.get("email id").toString();

I just used Gson

HashMap<String, Object> map = new Gson().fromJson(json.toString(), HashMap.class);

Here is Vikas's code ported to JSR 353:

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.json.JsonArray;
import javax.json.JsonException;
import javax.json.JsonObject;

public class JsonUtils {
    public static Map<String, Object> jsonToMap(JsonObject json) {
        Map<String, Object> retMap = new HashMap<String, Object>();

        if(json != JsonObject.NULL) {
            retMap = toMap(json);
        }
        return retMap;
    }

    public static Map<String, Object> toMap(JsonObject object) throws JsonException {
        Map<String, Object> map = new HashMap<String, Object>();

        Iterator<String> keysItr = object.keySet().iterator();
        while(keysItr.hasNext()) {
            String key = keysItr.next();
            Object value = object.get(key);

            if(value instanceof JsonArray) {
                value = toList((JsonArray) value);
            }

            else if(value instanceof JsonObject) {
                value = toMap((JsonObject) value);
            }
            map.put(key, value);
        }
        return map;
    }

    public static List<Object> toList(JsonArray array) {
        List<Object> list = new ArrayList<Object>();
        for(int i = 0; i < array.size(); i++) {
            Object value = array.get(i);
            if(value instanceof JsonArray) {
                value = toList((JsonArray) value);
            }

            else if(value instanceof JsonObject) {
                value = toMap((JsonObject) value);
            }
            list.add(value);
        }
        return list;
    }
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;


public class JsonUtils {

    public static Map<String, Object> jsonToMap(JSONObject json) {
        Map<String, Object> retMap = new HashMap<String, Object>();

        if(json != null) {
            retMap = toMap(json);
        }
        return retMap;
    }

    public static Map<String, Object> toMap(JSONObject object) {
        Map<String, Object> map = new HashMap<String, Object>();

        Iterator<String> keysItr = object.keySet().iterator();
        while(keysItr.hasNext()) {
            String key = keysItr.next();
            Object value = object.get(key);

            if(value instanceof JSONArray) {
                value = toList((JSONArray) value);
            }

            else if(value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            map.put(key, value);
        }
        return map;
    }

    public static List<Object> toList(JSONArray array) {
        List<Object> list = new ArrayList<Object>();
        for(int i = 0; i < array.size(); i++) {
            Object value = array.get(i);
            if(value instanceof JSONArray) {
                value = toList((JSONArray) value);
            }

            else if(value instanceof JSONObject) {
                value = toMap((JSONObject) value);
            }
            list.add(value);
        }
        return list;
    }
}