随机生成几位字母加数字的混合字符串

import java.util.Random;

public class RandomGenerator{
    //如果字符种类不够，可以自己再添加一些
    private static String range = "0123456789abcdefghijklmnopqrstuvwxyz";

    public static synchronized String getRandomString(){
        
        Random random = new Random();

        StringBuffer result = new StringBuffer();
//要生成几位，就把这里的数字改成几
        for ( int i = 0; i < 8; i++ ){
            
            result.append( range.charAt( random.nextInt( range.length() ) ) );
        
        }

        return result.toString();
    }
    public static void main(String[] args) {
        System.out.println(getRandomString());
    }
}