RandomUtil.java

package cn.wisenergy.chnmuseum.party.common.util;

public class RandomUtil {

	/**
	 * 创建指定数量的随机字符串
	 * 
	 * @param length
	 * @return
	 */
	public static String createRandom(int length) {
		String retStr = null;
		String strTable = "1234567890";
		int len = strTable.length();
		boolean bDone = true;
		do {
			retStr = "";
			int count = 0;
			for (int i = 0; i < length; i++) {
				double dblR = Math.random() * len;
				int intR = (int) Math.floor(dblR);
				char c = strTable.charAt(intR);
				if (('0' <= c) && (c <= '9')) {
					count++;
				}
				retStr += strTable.charAt(intR);
			}
			if (count >= 2) {
				bDone = false;
			}
		} while (bDone);
		return retStr;
	}

	public static String createLetterRandom(int length) {
		String retStr = null;
		String strTable = "1234567890abcdefghijklmnopqrstuvwxyz";
		int len = strTable.length();
		boolean bDone = true;
		do {
			retStr = "";
			int count = 0;
			for (int i = 0; i < length; i++) {
				double dblR = Math.random() * len;
				int intR = (int) Math.floor(dblR);
				char c = strTable.charAt(intR);
				if (('0' <= c) && (c <= '9')) {
					count++;
				}
				retStr += strTable.charAt(intR);
			}
			if (count >= 2) {
				bDone = false;
			}
		} while (bDone);
		return retStr;
	}

}