正则匹配
String result = buffer.toString();
??// 正则替换掉 类似<option value='' >请先选择:学科门类</option>代码
??String regEx = "<option value='' >(请先选择:\\S+)</option>";
??Pattern pattern=Pattern.compile(regEx,Pattern.DOTALL);
??Matcher matcher=pattern.matcher(result);
??if(matcher.find()){
???result=matcher.replaceAll("<option value='' >--请选择--</option>");
??}