常用的工具类

以你之姓@ 2024-03-22 14:40 47阅读 0赞

### 1.生成4/6位随机数 ###

public class RandomDigitUtil {
        
    
        private static final Random random = new Random();
    
        private static final DecimalFormat fourdf = new DecimalFormat("0000");
    
        private static final DecimalFormat sixdf = new DecimalFormat("000000");
    
        /**
         * 生成4位随机数
         */
        public static String getFourBitRandom() {
        
            return fourdf.format(random.nextInt(10000));
        }
    
        /**
         * 生成6位随机数
         */
        public static String getSixBitRandom() {
        
            return sixdf.format(random.nextInt(1000000));
        }
    }

### 2.Md5 ###

public final class MD5 {
        
        public static String encrypt(String strSrc) {
        
            try {
        
                char hexChars[] = {
         '0', '1', '2', '3', '4', '5', '6', '7', '8',
                        '9', 'a', 'b', 'c', 'd', 'e', 'f' };
                byte[] bytes = strSrc.getBytes();
                MessageDigest md = MessageDigest.getInstance("MD5");
                md.update(bytes);
                bytes = md.digest();
                int j = bytes.length;
                char[] chars = new char[j * 2];
                int k = 0;
                for (int i = 0; i < bytes.length; i++) {
        
                    byte b = bytes[i];
                    chars[k++] = hexChars[b >>> 4 & 0xf];
                    chars[k++] = hexChars[b & 0xf];
                }
                return new String(chars);
            } catch (NoSuchAlgorithmException e) {
        
                e.printStackTrace();
                throw new RuntimeException("MD5加密出错！！+" + e);
            }
        }
    }