随机生成字母数字的组合

来源：互联网发布：go高级编程书籍编辑：程序博客网时间：2024/05/17 00:04
随机数和随机字符串在开发中频繁的使用，本篇的demo可以直接封装成为一个实体类，使用的时候直接调用里面的对应方法即可
import java.util.Random; public class StringUtil {    private static final int Num_WORD = 1;//数字    private static final int STR_WORD = 2;//字母    private static final int STR_NUM_WORD = 3;//字母数字    private static final int MIX_WORD = 4;//字母数字符号     /**     * 获取随机字符串     * @param style  输出格式  1纯数字，2纯字符串，3字符数字组合，4字符数字符号组合。     * @param length 输出长度     * */     public static String getRandomStr(int style, int length) {          if (style == Num_WORD) {                return getNumRandom(length);            } else if (style == STR_WORD) {                return getStrRandom(length);            } else if (style == STR_NUM_WORD) {                return getStrNumRandom(length);            }else if (style == MIX_WORD) {                return getMixRandom(length);            }else{                  return getMixRandom(length);              }          }     //纯数字    private static String getNumRandom(int length) {        int[] array = new int[length];        StringBuilder str = new StringBuilder();        for (int i = 0; i < length; i++) {            array[i] = (int) (Math.random() * 10);            str.append(array[i]);        }        return str.toString();    }     //纯字母    private static String getStrRandom(int length) {        int[] array = new int[length];        char[] chars = new char[length];        StringBuilder str = new StringBuilder();        for (int i = 0; i < length; i++) {            while (true) {                array[i] = (int) (Math.random() * 1000);                if ((array[i] > 64 && array[i] < 91)                        || (array[i] > 96 && array[i] < 123))                    break;            }            chars[i] = (char) array[i];            str.append(chars[i]);        }        return str.toString();    }     //字母数字组合    public static String getStrNumRandom(Integer length) {         StringBuilder str = new StringBuilder();        Random random = new Random();         for (int i = 0; i < length; i++) {             boolean b = random.nextBoolean();             if (b) { // 字符串                 int choice = random.nextBoolean() ? 65 : 97; //取得65大写字母还是97小写字母                 str.append((char) (choice + random.nextInt(26)));// 取得大写字母             } else { // 数字                 str.append(random.nextInt(10));             }         }         return str.toString();     }          //字母数字符号组合    private static String getMixRandom(int length) {        int[] array = new int[length];        char[] chars = new char[length];        StringBuilder str = new StringBuilder();         for (int i = 0; i < length; i++) {            while (true) {                array[i] = (int) (Math.random() * 1000);                if (array[i] > 47 && array[i] < 91 || (array[i] > 96 && array[i] < 123))                    break;            }            chars[i] = (char) array[i];            str.append(chars[i]);        }        return str.toString();    }         public static void main(String[] args) {        System.out.println(StringUtil.getRandomStr(4, 10));    }}
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