content = content.replaceAll("?[^>]+>", ""); //替换HTML标签
content = content.replaceAll(" ", ""); //替换空格
content = content.replaceAll("<", "<"); //替换小于号
content = content.replaceAll(">", ">"); //替换大于号
content = content.replaceAll("\\s*|\t|\r|\n",""); //去除字符串中的空格,回车,换行符,制表符