JAVA 从字符串中提取数字

public void test() {
 2         String a = "hada16@54$1wd!6a41$da1dw5d6&a1d&a41d*w6d14a#d61d";
 3         /*
 4          * 正则表达式(一般用这个)
 5          * 
 6          * */
 7         String regEx = "[^0-9]";
 8         Pattern p = Pattern.compile(regEx);
 9         Matcher m = p.matcher(a);
10         String str = m.replaceAll("").trim();
11         System.out.println(str);//1654164115614161461
12         /*
13          * 
14          * 用字符串处理
15          * */
16         a = a.trim();
17         String b = "";
18         if(a != null && !"".equals(a)) {
19             for (int i = 0; i < a.length(); i++) {
20                 if (a.charAt(i)>=48 && a.charAt(i)<=57) {
21                     b+= a.charAt(i);
22                 }
23             }
24         }
25         System.out.println(b);//1654164115614161461
26     }