public class SerialNumberUtil { private static final Pattern pattern = Pattern.compile( "[0-9]*" ); private static final StringBuffer strJoint = new StringBuffer (); * @param prefix 前缀 * @param code 字母流水号 * @param len 位数 * @return public static final synchronized String getNextUppercaseSerialNumber (String prefix, String code, int len) { String str = getNextUppercaseSerialNumber(code, len); strJoint.setLength( 0 ); return strJoint.append(prefix).append(str).toString(); * 大写字母流水号递增 * * 字母前缀 + 数字位 = 4位， * * 数字位全为9 进一位字母 * * 最大支持 0001 ~ ZZZZ -> 717948 * @param code * @param len * @return public static final synchronized String getNextUppercaseSerialNumber (String code, int len) { if (code.length() > len) { throw new RuntimeException ( "流水号位数已经超" + len); strJoint.setLength( 0 ); // 纯数字 if (isNumeric(code)) { strJoint.append(getConvertNum(Integer.valueOf(code) + 1 , 4 )); // 超出长度限制,默认A00..1开始 if (strJoint.length() > len) { strJoint.setLength( 0 ); strJoint.append( "A" ).append(getRepeatCode( "0" , len - 2 )).append( "1" ); return strJoint.toString(); if (code.equals(getRepeatCode( "Z" , len))) { return code; // 取字母前缀，数字后缀 String prefix = getUppercasePrefix(code); // 前缀字母位相同，字母递增 if (prefix.length() == len) { prefix = getNextUppercase(prefix, len); return prefix; String suffix = code.substring(code.lastIndexOf(prefix) + prefix.length()); // 数字位全为9，字母进一位， if (suffix.equals(getRepeatCode( "9" , suffix.length()))) { // 特性处理，Y999 -> Z001 if (prefix.length() == 1 && prefix.equals( "Y" )) { strJoint.setLength( 0 ); strJoint.append( "Z" ).append(getRepeatCode( "0" , len - prefix.length() - 1 )).append( "1" ); return strJoint.toString(); prefix = getNextUppercase(prefix, len); if (prefix.length() == len) { return prefix; strJoint.setLength( 0 ); strJoint.append(prefix).append(getRepeatCode( "0" , len - prefix.length() - 1 )).append( "1" ); return strJoint.toString(); // 递增 strJoint.setLength( 0 ); strJoint.append(prefix).append(getConvertNum(Integer.parseInt(suffix) + 1 , suffix.length())); return strJoint.toString(); * 字母递增 * @param prefix * @return public static final synchronized String getNextUppercase (String prefix, int len) { char [] chars = prefix.toCharArray(); prefix = String.valueOf(getNextChar(chars, chars.length - 1 )); // 新增一位字母 if (prefix.length() < len && prefix.equals(getRepeatCode( "Z" , prefix.length()))) { strJoint.setLength( 0 ); strJoint.append(getRepeatCode( "A" , prefix.length() + 1 )); return strJoint.toString(); return prefix; * 字母位数递增 * @param chars * @param index * @return public static final char [] getNextChar( char [] chars, int index) { // 首位已经是Z，无法递增，直接访问 if ( 0 == index && "Z" .equals(String.valueOf(chars[ 0 ]))) { return chars; // 下标位是Z，上移一位,当前变为A if ( "Z" .equals(String.valueOf(chars[index]))) { // 字母A char last = ( char ) (chars[index] - 25 ); chars[index] = last; return getNextChar(chars, index - 1 ); // 字母递增 char last = ( char ) (chars[index] + 1 ); chars[index] = last; return chars; * 获取重复位数 * @param s * @param len * @return public static final String getRepeatCode (String s, int len) { return String.join(StrUtil.EMPTY, Collections.nCopies(len, s)); * 位数补全 * @param num * @param len * @return public static final String getConvertNum ( int num, int len) { return String.format( "%0" + len + "d" , num); * 判断数字格式 * @param str * @return public static final boolean isNumeric (String str) { return pattern.matcher(str).matches(); * 获取大写字母前缀 * @param str * @return public static final String getUppercasePrefix (String str) { return str.replaceAll( "\s*" , "" ).replaceAll( "[^(A-Z)]" , "" ); public static void main (String[] args) { Set<String> list = new HashSet <>(); String code = "0" ; try ( FileOutputStream fileOutputStream = new FileOutputStream ( new File ( "d:/case.txt" ))) { for ( int i = 0 ; i < 1000000 ; i++) { code = getNextUppercaseSerialNumber(code, 4 ); if (!list.add(code)) { throw new RuntimeException (String.format( "已存在：Code=%s，Index=%s \r\n" , code, i)); String msg = String.format( "Code=%s，Index=%s \r\n" , code, i); fileOutputStream.write(msg.getBytes()); } catch (Exception e) { e.printStackTrace(); Sam519