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cn.luues.tool.captcha.graphical.base.Randoms Maven / Gradle / Ivy
package cn.luues.tool.captcha.graphical.base;
import java.security.SecureRandom;
/**
* 随机数工具类
* Created by Mr-wu
*/
public class Randoms {
protected static final SecureRandom RANDOM = new SecureRandom();
// 定义验证码字符.去除了0、O、I、L等容易混淆的字母
public static final char ALPHA[] = {'2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
protected static final int numMaxIndex = 8; // 数字的最大索引，不包括最大值
protected static final int charMinIndex = numMaxIndex; // 字符的最小索引，包括最小值
protected static final int charMaxIndex = ALPHA.length; // 字符的最大索引，不包括最大值
protected static final int upperMinIndex = charMinIndex; // 大写字符最小索引
protected static final int upperMaxIndex = upperMinIndex + 23; // 大写字符最大索引
protected static final int lowerMinIndex = upperMaxIndex; // 小写字母最小索引
protected static final int lowerMaxIndex = charMaxIndex; // 小写字母最大索引
/**
* 产生两个数之间的随机数
*
* @param min 最小值
* @param max 最大值
* @return 随机数
*/
public static int num(int min, int max) {
return min + RANDOM.nextInt(max - min);
}
/**
* 产生0-num的随机数,不包括num
*
* @param num 最大值
* @return 随机数
*/
public static int num(int num) {
return RANDOM.nextInt(num);
}
/**
* 返回ALPHA中的随机字符
*
* @return 随机字符
*/
public static char alpha() {
return ALPHA[num(ALPHA.length)];
}
/**
* 返回ALPHA中第0位到第num位的随机字符
*
* @param num 到第几位结束
* @return 随机字符
*/
public static char alpha(int num) {
return ALPHA[num(num)];
}
/**
* 返回ALPHA中第min位到第max位的随机字符
*
* @param min 从第几位开始
* @param max 到第几位结束
* @return 随机字符
*/
public static char alpha(int min, int max) {
return ALPHA[num(min, max)];
}
}
