Java tutorial
//package com.java2s; /* * jPOS Project [http://jpos.org] * Copyright (C) 2000-2012 Alejandro P. Revilla * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.nio.ByteBuffer; import java.util.Arrays; public class Main { public static byte[] padRight(byte[] tgt, int len, byte padding) { if (tgt.length >= len) { return tgt; } byte[] paddings = new byte[len - tgt.length]; Arrays.fill(paddings, padding); ByteBuffer buffer = ByteBuffer.allocate(len); buffer.put(tgt); buffer.put(paddings); return buffer.array(); } /** * pad to the right * * @param s - * original string * @param len - * desired len * @param c - * padding char * @return padded string * @ if String's length greater than pad length */ public static String padright(String s, int len, char c) { s = s.trim(); if (s.length() > len) throw new RuntimeException("invalid param:" + s + " invalid len " + s.length() + "/" + len); StringBuilder d = new StringBuilder(len); int fill = len - s.length(); d.append(s); while (fill-- > 0) d.append(c); return d.toString(); } /** * trim String (if not null) * @param s String to trim * @return String (may be null) */ public static String trim(String s) { return s != null ? s.trim() : null; } /** * Trims a byte[] to a certain length * @param array the byte[] to be trimmed * @param length the wanted length * @return the trimmed byte[] */ public static byte[] trim(byte[] array, int length) { byte[] trimmedArray = new byte[length]; System.arraycopy(array, 0, trimmedArray, 0, length); return trimmedArray; } }