extjs解决bean转换为json对象的死循环的问题

public void query() throws Exception{
		List<Account> accounts = accountService.query();
		
		JsonConfig config = new JsonConfig();
		config.setExcludes(new String[]{"card","borrows","storeins","accountlevel"});
		
		
		JSONArray array = new JSONArray();
		JSONObject jsonObject = new JSONObject();
		
		String t = array.fromObject(accounts, config).toString();
		
		System.out.println("this is +=======================+"+accounts.size());
		//将结果进行输出
		ServletActionContext.getResponse().setContentType("text/html;charset=utf-8");
		ServletActionContext.getResponse().getWriter().print(t);
	}

做法就是将导致死循环的属性删除。

所遇见的错误是：

异常信息如下: There is a cycle in the hierarchy!