Here you can find the source of base64Encode(int value)
public static String base64Encode(int value)
//package com.java2s; /*//from w w w . ja va 2 s .c o m * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ public class Main { private static final char[] _BASE_64_CHARS = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', // 0-9 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', // 10-19 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', // 20-29 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 30-39 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', // 40-49 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', // 50-59 '8', '9', '_', '-' // 60-63 }; /** * Utility method for producing a (psuedo) base 64 encoding * of an int value, suitable for inclusion in a file name. * This is used by NameProviders to include a semi-unique * identifier (ie. the base 64 encoded hash code) in the * image file names in order to avoid name collisions. */ public static String base64Encode(int value) { StringBuffer buffer = new StringBuffer(6); // For now, let's just use the lower 3 bytes. This increases // the possibility of collisions, but it allows us to go // from a 6 char to 4 char id. for (int i = 0; i < 4; i++) buffer.append(_BASE_64_CHARS[((value >> (6 * i)) & 0x3f)]); return buffer.toString(); } }