生成随机码

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();
}