关于Java中的数组转变成字符串问题

private static String arraytoString(int arr[]){ StringBuilder sb=new StringBuilder(); sb.append("["); for (int i = 0; i < arr.length; i++) {if(i==arr.length-1){sb.append(arr[i]);}else {sb.append(arr[i]).append(", ");}} sb.append("]");return sb.toString(); }

private static void bianli(int arr[]){ System.out.print("["); int i; for (i = 0; i < arr.length; i++) {if(i==arr.length-1){System.out.println(arr[i]+"]");}else {System.out.print(arr[i]+", ");}} }

private static String arraytoString1(int arr[]){ String s=""; s+="["; for (int i = 0; i < arr.length; i++) {if(i==arr.length-1){s+=arr[i];}else {s+=arr[i];s+=", ";}} s+="]";return s; }