JAVA正则表达式替换字符串问题

public static void main(String[] args) {

String regex = "<!-- start_page -->[\\s\\S]*<!-- end_page -->";

String str = "dsagfg<!-- start_page -->dsgdr <!-- end_page -->sdafdgrtuy";

Pattern pat = Pattern.compile(regex);

Matcher matcher = pat.matcher(str);

while (matcher.find()) {

String temp = str.substring(matcher.start(), matcher.end());

System.out.println(temp);

str = str.replaceAll(temp, "");

matcher = pat.matcher(str);

}

System.out.println(str);

}