Read javascript object in java

Question

I have a javascript object like follows.

{
    "name": {
        "type": "text",
        "onClick": function () {
            console.log("Hello");
        }
    }
}

It is stored in string format in Java like.

String obj = "{ \"name\": { \"type\": \"text\", \"onClick\": function () { console.log(\"Hello\"); } } }";

I'm trying to figure out a way to read this obj in Java and traverse through the object graph like we can with JSON using Jackson if it didn't have function declaration.

Is there any Java library to read/parse a string representing javascript object (not just JSON) and traverse through the object graph?

@PritamBanerjee I looked at the documentation but couldn't figure out how Apache Wink could help read javascript object in java? Can you please reference to specific sections in documentation? — TheKojuEffect, Jan 08 '16 at 05:51
I was one of the flaggers (well, voted to close) because asking for library recommendations is off-topic on StackOverflow. Try [Software Recommendations](http://softwarerecs.stackexchange.com) — Vince, Jan 08 '16 at 05:54
That is not JSON. It can't be parsed using the standard libraries — OneCricketeer, Jan 08 '16 at 05:56
@cricket_007 It is fine if there are any non-standard libraries to parse a string representing javascript object. — TheKojuEffect, Jan 08 '16 at 05:59
I see what you are saying. I usually use Apache wink. Let me see if I can find anything for you. — Pritam Banerjee, Jan 08 '16 at 06:01
I don't even know what you want to parse out of that string... — OneCricketeer, Jan 08 '16 at 06:02
@cricket_007 I am looking for similar functionalities that are provided by Jackson for JSON like parsing that string to create a (say) `JavaScriptObjectNode` and traversing through that object. — TheKojuEffect, Jan 08 '16 at 06:06
Possible duplicate of [Javascript parser for Java](http://stackoverflow.com/questions/6511556/javascript-parser-for-java) — OneCricketeer, Jan 08 '16 at 06:09

score 3 · Answer 1 · answered Jan 08 '16 at 07:11

You could use Java's ScriptEngine and the Javascript built-in. Something like,

String obj = "{'name':{'type': 'text', 'onClick': function (){console.log('Hello')}}}";
try {
    ScriptEngine se = new ScriptEngineManager().getEngineByName("js");
    se.eval(String.format("Object.bindProperties(this, %s);", obj));
    se.eval("print(this.name.onClick)");
} catch (ScriptException e) {
    e.printStackTrace();
}

which can read the function declaration (and any of the other obj properties).

score 1 · Answer 2 · answered Jan 08 '16 at 05:41

1

You can use object mapper from jackson libarary to convert jsonString to hash map

import com.fasterxml.jackson.databind.ObjectMapper;

private Map<String, Object> getMapFromJson(String json){

    Map<String,Object> map = new HashMap<String,Object>();
    ObjectMapper mapper = new ObjectMapper();

    try {
        //convert JSON string to Map
        map = mapper.readValue(String.valueOf(json), new TypeReference<Map<String, Object>>() {} );
       return map;
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
}

answered Jan 08 '16 at 05:41

Neel

86
3

Jackson is working only for JSON. i.e without function declarations. – TheKojuEffect Jan 08 '16 at 05:47
The point is if JSON string is just a key value pair. by this you will get your function as a value to the key 'onClick'. I.e a string. If you need a function to be parsed. you need to look for javascript parser implementation in java . – Neel Jan 08 '16 at 06:00

score 0 · Answer 3 · answered Jan 08 '16 at 06:43

0

I suggest library org.json : JavaDoc URL, jar file Download

[Example]

String obj = "{ \"name\": { \"type\": \"text\", \"onClick\": function () { console.log(\"Hello\"); } } }";
JSONObject json = new JSONObject(obj);
JSONObject subJson = new JSONObject();

if( ! json.isNull("name") ){ //Determine if the value associated with the key("name") is null or if there is no value.
     subJson = json.getJSONObject("name");
     if( ! subJson.isNull("type") ){ // Determine if the value associated  with the key("type") is null or if there is no value.
        subJson.getString("type"); // get the value : "text"
        subJson.put("newData", "text2"); // data added under the "onclick"
    }
}

answered Jan 08 '16 at 06:43

botem

348
1
11

Not Working. org.json.JSONException: Expected a ',' or '}' at character 52 – TheKojuEffect Jan 08 '16 at 06:49
Could you replace your value like "function () { console.log(\"Hello\"); "? – botem Jan 08 '16 at 06:52
"org.json" can read value only String or Number. if you want to put String value, use ""(Double Quote) – botem Jan 08 '16 at 06:53

Read javascript object in java

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