How do I convert java.lang.String to java.util.LinkedHashMap

Question

I converted java.lang.String to or.simple.json.JSONObject. Now I'm unable to cast it to HashMap.

org.json.JSONObject jso = new org.json.JSONObject("{"phonetype":"N95","cat":"WP"}");        
LinkedHashMap h = (LinkedHashMap) jso.get("phonetype");
System.out.println(h);

and I'm getting an error:

"java.lang.String cannot be cast to java.util.LinkedHashMap"

Please look into this stackoverflow answer: https://stackoverflow.com/questions/22011200/creating-hashmap-from-a-json-string — Pradip Karki, Aug 30 '18 at 17:20
duplicate of https://stackoverflow.com/questions/22011200/creating-hashmap-from-a-json-string — Vaibhav Gupta, Aug 30 '18 at 17:21
Possible duplicate of [creating Hashmap from a JSON String](https://stackoverflow.com/questions/22011200/creating-hashmap-from-a-json-string) — Micheal O'Dwyer, Aug 30 '18 at 17:40

score 1 · Answer 1 · answered Aug 30 '18 at 17:35

JSONObject has following constructor

public JSONObject(Map map) { super(map); }

This means you cannot create JSONObject, passing String in consctructor. But you can using map

Map<String, String> map = new LinkedHashMap<>();
    map.put("phonetype","N95");
    map.put("cat", "WP");
    JSONObject jso = new JSONObject(map);

get method has signature

public V get(Object key)

This means that if you want to get map, value should be Map generic. For example

        Map<String, String> map = new LinkedHashMap<>();
    map.put("phonetype","N95");
    map.put("cat", "WP");

    Map<String, Map> toConstructor = new LinkedHashMap() {{
        put("map", map);
    }};
    JSONObject jso = new JSONObject(toConstructor);
    LinkedHashMap h = (LinkedHashMap) jso.get("map");
    System.out.println(h);

In your case you try to cast String to LinkedHashMap, so ClassCastException was thrown

How do I convert java.lang.String to java.util.LinkedHashMap

1 Answers1