package com.qfx.util;
import java.util.Random;
public class CharacterUtils {
	// 得到一个随机数，length是要产生的随机数的长度
	public static String getRandomString(int length) {
		String str = "abcdefghigklmnopqrstuvwxyzABCDEFGHIGKLMNOPQRSTUVWXYZ1234567890";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();

		for (int i = 0; i < length; i++) {
			// 从1-62的字符中随机取出一位
			int number = random.nextInt(62);
			sb.append(str.charAt(number));
		}
		return sb.toString();
	}

	// 得到一个随机数
	public static String getRandomString2(int length) {
		Random random = new Random();
		StringBuffer sb = new StringBuffer();

		for (int i = 0; i < length; i++) {
			int number = random.nextInt(3);
			long result = 0;

			switch (number) {
			case 0:
				// 随机得到大写字母A-Z一个字符
				result = Math.round(Math.random() * 25 + 65);
				sb.append(String.valueOf((char) result));
				break;
			case 1:
				// 随机得到小写字母a-z一个字符
				result = Math.round(Math.random() * 25 + 97);
				sb.append(String.valueOf((char) result));
				break;
			case 2:
				// 随机得到0-9之间的一个数
				sb.append(String.valueOf(new Random().nextInt(10)));
				break;
			}
		}
		return sb.toString();
	}

	public static void main(String[] args) {
		System.out.println(getRandomString(10));
		System.out.println(getRandomString2(10));
	}
}