JOSNP用JS引擎转MAP

    String jsFun = "function callback(json) {return json};";
    ScriptEngineManager engineManager = new ScriptEngineManager();
    ScriptEngine engine = engineManager.getEngineByMimeType("text/javascript");

    engine.eval(jsFun);
    Map<?, ?> json = (Map<?, ?>) engine.eval(unionid);