格式化数据保留两位小数，输入格式为 ：xxx,xx,,,,x,,(x为浮点数)

/**
	 * 格式化字符串
	 */
	static String dataFormat(String data){
		String formatedData = "";
		// 浮点数正则表达式
		Pattern pattern = Pattern.compile("^(-?\\d+)(\\.\\d+)?$");
		if(data == null) return null;
		else {
			if(data.equals("")) formatedData = "";
			else if(!data.contains(",")){
				try {
					formatedData += new BigDecimal(data).setScale(2, BigDecimal.ROUND_HALF_UP);
				} catch (Exception e) {
					// 排除数据错误的情况 比如“-” “null”类型的
					formatedData += data;
				}
			} else{
				while(data.length() != 0){
					int position = data.indexOf(",");
					if(data.indexOf(",") != -1){
						String tempString = data.substring(0, position);
						if(pattern.matcher(tempString).matches() ){
							formatedData += new BigDecimal(tempString).setScale(2, BigDecimal.ROUND_HALF_UP);
							formatedData += ",";
							data = data.substring(position + 1);
						}else if (tempString.equals("")) {
							formatedData += ",";
							data = data.substring(position + 1);
						}else{
							return "格式不正确";
						}
					}else{
						// 最后一个值
						formatedData += new BigDecimal(data).setScale(2, BigDecimal.ROUND_HALF_UP);
						formatedData += ",";
						data = "";
					}
				}
			}
		}
		return formatedData;
	}