工具类-随机字符串

import java.util.Random;

/**
 * RandomString.java
 * utils class
 * @author fanfq
 * @version 1.0  2009-6-4
 * */
public class RandomString {
	
	/**返回大写随机字母字符串*/
	public static String getRandomStringU(int length){
		String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(26);
			sb.append(str.charAt(number));
		}		
		return sb.toString();
	}
	
	/**返回小写随机字母字符串*/
	public static String getRandomStringL(int length){
		String str = "abcdefghijklmnopqrstuvwxyz";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(26);
			sb.append(str.charAt(number));
		}		
		return sb.toString();
	}
	
	/**返回随机数字字符串[0-9]*/
	public static String getRandomStringN10(int length){
		String str = "0123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(10);
			sb.append(str.charAt(number));
		}		
		return sb.toString();
	}
	
	/**返回随机数字字符串[1-9]*/
	public static String getRandomStringN9(int length){
		String str = "123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(9);
			sb.append(str.charAt(number));
		}		
		return sb.toString();
	}
	
	/**返回随机数字[1-9]*/
	public static int getRandomIntN9(int length){
		String str = "123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(9);
			sb.append(str.charAt(number));
		}		
		return Integer.parseInt(sb.toString());
	}
	
	/**返回随机数字[0-9]*/
	public static int getRandomIntN10(int length){
		String str = "0123456789";
		Random random = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=0;i<length;++i){
			int number = random.nextInt(10);
			sb.append(str.charAt(number));
		}		
		return Integer.parseInt(sb.toString());
	}	
	
	/**返回大小写字母及数字混合的字符串*/
	public static String getRandomStringA(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 + 64);
				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();
	}
	
}