将Java Map转换为Javascript Map

Question

I have a Java Map. I want to convert it in to JavaScript map.

The java function to convert as JS map follows:

private Object getJSLocalizedValueMap() {

    Map<String, String> langSel = new HashMap<String, String>();
    langSel.add("en", true);
    langSel.add("de", false);
    langSel.add("fr", false);

    //Now convert this map into Javascript Map
    NativeObject nobj = new NativeObject();
    ScriptEngineManager factory = new ScriptEngineManager();
    ScriptEngine engine = factory.getEngineByName("javascript");
    for (Map.Entry<String, String> entry : langSel.entrySet()) {
        nobj.defineProperty(entry.getKey(), entry.getValue(), NativeObject.READONLY);
    }
    engine.put("langSel", nobj);
    return langSel;
}

In the JSP page's javascript the code is:

var langs = ${messagesJS};

In Javascript, I got:

langs = {en=true, de=false, fr=false};

instead of

langs = {"en":true, "de":false, "fr":false}

Please suggest me how to achieve this?

Answer 1

You might be able to use the JSONObject class for this. It has a constructor that you pass in a Map . Call that and then call the toString() method and it should give you a JS array.

http://www.json.org/javadoc/org/json/JSONObject.html#JSONObject%28java.util.Map%29

So something like:

Map<String, String> langSel = new HashMap<String, String>();
langSel.add("en", true);
langSel.add("de", false);
langSel.add("fr", false);

JSONObject jsonObj = new JSONObject(langSel);
engine.put("langSel", jsonObj.toString());

You will need to make sure the org.json.JSONObject class is on your classpath. Either download the JAR and add to classpath manually (through Eclipse or something) or if you are using Maven use a dependency like the following:

  <dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20070829</version>
  </dependency>

If you are not using Maven, you can still download the JAR from here: http://mvnrepository.com/artifact/org.json/json/20090211

Answer 2

Instead of below line

langSel.add("en", true);

use this line

langSel.add("\"en\"", true);

Try this it might helpful.