生成字母+数字的随机数

package demo;
import java.util.Random;

/**
 * 生成字母+数字的随机数
 * @author sy
 *
 */
public class Demo{

    public static void main(String[] args){
        System.out.println(getStringRandom(6));
    }

     public static String getStringRandom(int length) {

         String val = "";
         Random random = new Random();
         //参数length，表示生成几位随机数
         for(int i = 0; i < length; i++) {
            String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
            //输出字母还是数字
            if("char".equalsIgnoreCase(charOrNum)){
                //输出是大写字母还是小写字母
                int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
                val += (char)(random.nextInt(26) + temp);
            }else if("num".equalsIgnoreCase(charOrNum)) {
                val += String.valueOf(random.nextInt(10));
            }
        }
        return val;
    }

}