StringBuilder sb=new StringBuilder();StringBuilder sd=new StringBuilder();for (int i = 0; i < 2; i++) {?? ?int index1=rd.nextInt(arr1.length);?? ?int index2=rd.nextInt(arr2.length);?? ?sb.append(arr1[index1]);?? ?sd.append(arr2[index2]);}System.out.println("驗(yàn)證碼為："+sb+sd);//1System.out.println(sb+sd);//2