产生随机字符串

转自：

http://www.iteye.com/topic/477460

 

public class RandomFileName {
	/**
	 * 产生一个随机的字符串
	 * 
	 * @param 字符串长度
	 * @return
	 */
	public static String getRandomString(int length) {
		String base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < length; i++) {
			int number = random.nextInt(base.length());
			sb.append(base.charAt(number));
		}
		return sb.toString();
	}

	public static void main(String[] args) {
		System.out.println(RandomFileName.getRandomString(5));
	}
}

 或者

public class RandomFileName2 {
	/**
	 * 产生一个随机的字符串
	 * 
	 * @param 字符串长度
	 * @return
	 */
	public static String getRandomString(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:
					result = Math.round(Math.random()*25+65);
					sb.append(String.valueOf((char)result));
					break;
				case 1:
					result = Math.round(Math.random()*25+97);
					sb.append(String.valueOf((char)result));
					break;
				case 2:
					sb.append(String.valueOf(new Random().nextInt(10)));
					break;
			}
		}
		return sb.toString();
	}
	
	public static void main(String[] args) {
		System.out.println(RandomFileName2.getRandomString(10));
	}
}