随机 工具类

package com.wc;

import java.io.UnsupportedEncodingException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Random;

public class RandomUtil {

	/**
	 * 生成指定范围的随机整数
	 * 
	 * @param min 最小值
	 * @param max 最大值
	 * @return
	 */
	public static int genInteger(Integer min, Integer max) {
		return (int) (Math.random() * (max - min + 1) + min); // ctrl+1
	}

	/**
	 * 生成长度随机的邮箱
	 * 
	 * @return
	 */
	public static String genEmail() {
		String[] emails = { "126", "163", "qq", "gmail", "hotmail", "outlook" };
		String[] suffix = { "com", "cn", "net", "org" };
		String tmp1 = genString(5, genInteger(6, 18));
		String tmp2 = emails[genInteger(0, emails.length - 1)];
		String tmp3 = suffix[genInteger(0, suffix.length - 1)];
		return tmp1 + "@" + tmp2 + "." + tmp3;
	}

	/**
	 * 随机生成电话号码
	 *
	 * @return
	 */
	public static String genPhoneNum() {
		String[] prefix = { "132", "133", "134", "135", "136", "138", "139", "152", "154", "155", "177", "188" };
		int index = genInteger(0, prefix.length - 1);
		String res = prefix[index] + genString(1, 8);
		return res;
	}

	/**
	 * 随机产生一个boolean值
	 *
	 * @return 返回true或false
	 */
	public static boolean genBoolean() {
		boolean res = genInteger(0, 1) == 0 ? true : false;
		return res;
	}

	/**
	 * 随机字符串：1纯数字，2纯小写，3纯大写，4大小写，5数字字母混合，6汉字字符串
	 * 
	 * @param type 类型
	 * @param len  长度
	 * @return
	 */
	public static String genString(Integer type, Integer len) {
		String res = "";
		switch (type) {
		case 1:
			for (int i = 0; i < len; i++) {
				res += genInteger(0, 9);
			}
			break;
		case 2:
			for (int i = 0; i < len; i++) {
				int min = (int) 'a';
				int max = (int) 'z';
				int tmp = genInteger(min, max);
				res += (char) tmp;
			}
			break;
		case 3:
			for (int i = 0; i < len; i++) {
				int min = (int) 'A';
				int max = (int) 'Z';
				int tmp = genInteger(min, max);
				res += (char) tmp;
			}
			break;
		case 4:
			for (int i = 0; i < len; i++) {
				int min = (int) 'A';
				int max = (int) 'z';
				int tmp = genInteger(min, max);
				if (tmp >= 91 && tmp = 91 && tmp = 58 && tmp