java 後臺驗證數據唯一性

	/**
	 * 判斷唯一
	 */
	@ResponseBody
	@RequestMapping(params = "method=isExist2")
	public AjaxMsg isExist2(HttpServletRequest request,
			HttpServletResponse response) throws Exception {
		
		AjaxMsg msg = new AjaxMsg();
		String id = request.getParameter("id");
		String xm = request.getParameter("xm");
		String xsid = request.getParameter("xsid");
		String xn = request.getParameter("xn");
		String xq = request.getParameter("xq");
		String kcmc = request.getParameter("kcmc");
		
		msg.setSuccess(false);
		msg.setMessage("修改失敗，["+xm+"]在該學年學期下的課程["+kcmc+"]，已有成績，不能重複添加！");
		CjEntity cj = this.cjService.getCjById(NumberUtil.format(id));
		if (cj != null) {
			boolean a = xsid.equals(cj.getXs().getId().toString());
			boolean b = xn.equals(cj.getXn());
			boolean c = xq.equals(cj.getXq());
			boolean d = kcmc.equals(cj.getKcmc());
			if (a == false || b == false || c == false || d == false) {  //驗證唯一性的條件是否變化  ,如果變化了，則判斷是否唯一
				int i = this.cjService.getCount(xn, xq, xsid, kcmc);
				if (i <= 0) {
					msg.setSuccess(true);
				}
			} else {
				msg.setSuccess(true);
			}
		}
		return msg;
	}