@Override
	public String toDocument(){
		if( content == null || content.size() == 0){
			return "";
		}
		String retString = "";
		String domHead ="<msg ";
		domHead += "WxId="+getWxId() +" SendTime="+getSendTime() + " MsgType="+getMsgType();
		for(WxMsgHtmlItemContent cnt : content ){
			WxMsgHtmlItemContentItem itm = cnt.getTxtContent();
			if(itm == null ) continue;
			String cntString =  itm.getContentString();
			if(  cntString == null || cntString.equals("") )
				continue;
			String dom = domHead + " TxtFile="+cnt.getTxtFile() + " PostDate="+ itm.getPostDateString()
			+ " PostUser=" + itm.getUserString()+" >\n";
			
			dom += itm.getContentString();
			retString += dom + "\n";
		}
		
		return retString;
	}