/**
	 * 获取表达式中${}中的值
	 * @param content
	 * @return
	 */
	public static String getContentInfo(String content) {
		Pattern regex = Pattern.compile("\\$\\{([^}]*)\\}");
		Matcher matcher = regex.matcher(content);
		StringBuilder sql = new StringBuilder();
		while(matcher.find()) {
			sql.append(matcher.group(1)+",");
		}
		if (sql.length() > 0) {
			sql.deleteCharAt(sql.length() - 1);
		}
		return sql.toString();
	}