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 String ar