Java 32位MD5加密的大写字符串

package Test;
import java.security.MessageDigest;
public class Main {
       
       public static void main(String[] args) {
             String result = MD5("1");
        System.out.println("result: " + result);
        System.out.println("length: " + result.length());
             
       }
       
        public final static String MD5(String s) {
               char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                       'A', 'B', 'C', 'D', 'E', 'F' };
               try {
                   byte[] btInput = s.getBytes();
                   // 获得MD5摘要算法的 MessageDigest 对象
                   MessageDigest mdInst = MessageDigest.getInstance("MD5");
                   // 使用指定的字节更新摘要
                   mdInst.update(btInput);
                   // 获得密文
                   byte[] md = mdInst.digest();
                   // 把密文转换成十六进制的字符串形式
                   int j = md.length;
                   char str[] = new char[j * 2];
                   int k = 0;
                   for (int i = 0; i < j; i++) {
                       byte byte0 = md[i];
                       str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                       str[k++] = hexDigits[byte0 & 0xf];
                   }
                   return new String(str);
               } catch (Exception e) {
                   e.printStackTrace();
                   return null;
               }
           }
       
}