Convert javascript array to java object

Question

I want to convert javascript multidimensional array to some java object. I have this array stored in string. Here is the example of array in my string

String array = "[1,2,3,[3,2,4],['asdasda','test','tsdsdf'],3,2,['sddd']]";

and structure can be in different this is just an example.

Is there any way to convert this array into some Java object?

Answer 1

Short answer: Yes. ;-)

Long answer: Considering how similar Java and JavaScript seem to be, this is surprisingly hard.

First of all, your input isn't in JSON format (for JSON, strings must use " quotes), so you can't use one of the many JSON parsing libraries like gson or jackson.

So the next option would be to use a JavaScript interpreter like Rhino, call evaluateString() and examine the result.

This gives you an JavaScript array instance which will feel very odd to use from a Java perspective - remember, JavaScript arrays are actually more like hash maps than plain Java arrays plus some JavaScript oddities.

If you want to get value 5 from such an array, you can use array.get(5, array);

Last option is to write your own parser.

Answer 2

To convert javascript to java object I use this function:

public <T> T toObject(String js, Class<T> classToReturn) throws ScriptException, JsonMappingException, JsonProcessingException {

    final ScriptEngineManager scriptEngineManager = new ScriptEngineManager();
    ScriptEngine scriptEngine = scriptEngineManager.getEngineByName("JavaScript");
    scriptEngine.eval("variable = " + js);
    scriptEngine.eval("json= JSON.stringify(variable);");
    final String json =  (String) scriptEngine.get("json");

    final ObjectMapper mapper = new ObjectMapper();
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

    return mapper.readValue(json, classToReturn);
}

Example:

    final String js = "[{name:'FieldName', numbers: [1,2,3], strings: ['one','two','three'], innerClass:[{name:'InnerClass1', numbers: [4,5,6]},{name:'InnerClass2', strings: ['test']}]},  {strings: ['asdasda','tsdsdf']}]";
    final ClassToGet[] objects = toObject(js, ClassToGet[].class);

Class to get:

@Getter @Setter @ToString
public class ClassToGet{
    private String name;
    private int[] numbers;
    private List<String> strings;
    private Set<ClassToGet> innerClass;
}