正则表达式获取匹配字符串

String s = "姓名是${name},密码是${password}";
Pattern pat = Pattern.compile("\$\{[a-zA-Z0-9_-]*\}");
Matcher mat = pat.matcher(s);
while(mat.find()){
String mm=mat.group(0);
String[] str=mm.split("\{");
String[] str2=str[1].split("\}");
System.out.println(str2[0]);

}