net.sf.json.JSONException: There is a cycle in the hierarchy

java 对象解析为字符串时出现死循环 解决方案：

String cardId=ActionUtil.getParameter("cardId");

List<MonthBudget> monthBudgets=fublishFeeService.queryFeePlan(cardId);

if(monthBudgets!=null && !"".equals(monthBudgets)){

JsonConfig jcf=new JsonConfig();

jcf.setJsonPropertyFilter(new PropertyFilter() {

@Override

public boolean apply(Object arg0, String arg1, Object arg2) {

// TODO 返回true就可过滤掉

if(arg1.equals("rollBudget")){

return true;

}

if(arg1.equals("monthBudget")){

return true;

}

return false;

}

});

JSONArray jsonArray = JSONArray.fromObject(monthBudgets,jcf);

ActionUtil.write(jsonArray.toString());

return;

}