public static String getRandomStr(){

Random random=new Random();

String randString = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";//用于随机产生字符串

StringBuffer sb=new StringBuffer();

for(int i=0;i<6;i++){

String valueOf = String.valueOf(randString.charAt(random.nextInt(randString.length())));

String rand = String.valueOf(valueOf);

sb.append(rand);

}

return sb.toString();

}