Android examples for java.util:Random String
get a fixed-length random string, its a mixture of uppercase and lowercase letters
//package com.java2s; import android.text.TextUtils; import java.util.Random; public class Main { public static final String LETTERS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; /**//w ww . j a va2 s . c o m * get a fixed-length random string, its a mixture of uppercase and lowercase letters * * @param length * @return * @see RandomUtils#getRandom(String source, int length) */ public static String getRandomLetters(int length) { return getRandom(LETTERS, length); } /** * get a fixed-length random string, its a mixture of chars in source * * @param source * @param length * @return <ul> * <li>if source is null or empty, return null</li> * <li>else see {@link RandomUtils#getRandom(char[] sourceChar, int length)}</li> * </ul> */ public static String getRandom(String source, int length) { return TextUtils.isEmpty(source) ? null : getRandom( source.toCharArray(), length); } /** * get a fixed-length random string, its a mixture of chars in sourceChar * * @param sourceChar * @param length * @return <ul> * <li>if sourceChar is null or empty, return null</li> * <li>if length less than 0, return null</li> * </ul> */ public static String getRandom(char[] sourceChar, int length) { if (sourceChar == null || sourceChar.length == 0 || length < 0) { return null; } StringBuilder str = new StringBuilder(length); Random random = new Random(); for (int i = 0; i < length; i++) { str.append(sourceChar[random.nextInt(sourceChar.length)]); } return str.toString(); } /** * get random int between 0 and max * * @param max * @return <ul> * <li>if max <= 0, return 0</li> * <li>else return random int between 0 and max</li> * </ul> */ public static int getRandom(int max) { return getRandom(0, max); } /** * get random int between min and max * * @param min * @param max * @return <ul> * <li>if min > max, return 0</li> * <li>if min == max, return min</li> * <li>else return random int between min and max</li> * </ul> */ public static int getRandom(int min, int max) { if (min > max) { return 0; } if (min == max) { return min; } return min + new Random(System.currentTimeMillis()).nextInt(max - min); } }