产生随机字符串(a-z A-Z 0-9)

实现方法一：

引用

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));  
    }  
} 

实现方法二：

引用

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));  
    }  
}