关于java调用js，document不能用问题

1.

 Document mydoc = null;
 public BareBonesBrowserLaunch(String url) throws MalformedURLException, IOException{
  mydoc = Jsoup.parse(new URL(url),30000);//利用Jsoup实现document树
 }

2.

public Element getElementById(){//实现document的方法
  System.out.println("Java println:\t"+mydoc.getElementById(id));
  return mydoc.getElementById(id);//返回的是Element对
 }

3.java中调用js

/**
  * 调用js中的方法
  * @throws Exception
  */
 public static void ExcuteJs(String url) throws Exception{
  ScriptEngineManager sem = new ScriptEngineManager();
  ScriptEngine se = sem.getEngineByName("JavaScript");
  String path =this.getServlet().getServletContext().getRealPath("/WEB-INF/js/jituan.js");
  
  File f = new File(path);
  Reader d = new InputStreamReader(new FileInputStream(f));
  se.eval(d); 
  Invocable inv = (Invocable) se;
  se.put("document", new BareBonesBrowserLaunch(url));关联对象，很重要，关联javascript的document对象为BareBonesBrowserLaunch，即自己实现的document对象
  String value = (String) inv.invokeFunction("load",url);
  
  System.out.println(value);
  
  
 

//直接调用js方法 

//  ScriptEngineManager factory = new ScriptEngineManager();
//  ScriptEngine scriptEngine = factory.getEngineByName("JavaScript");
//  try {
//  // String script = "function load(url){var dom=null;if(document.implementation && document.implementation.createDocument){dom=new window.XMLHttpRequest();}else{dom=new ActiveXObject(\"Microsoft.XMLHttp\");} dom.open(\"GET\",url,false); dom.send(null); return dom;}";
//   
//  // se.eval(script);
//   Invocable inv2 = (Invocable) se;
//   String res=(String)inv.invokeFunction("load",url);
//   
//   System.out.println(res);
//   }catch(Exception e){e.printStackTrace();}  
 }