简单的泛型方法

//===========================================================
//泛型方法
 (main)
String[] names = {"小鹿","小羊","小牛","小河"};
printArray(names);

Integer[] ages = {14,22,33,55};
printArray(ages);

public static <T> void printArray(T[] arr){
    //先判断数组是否为 null
    if (arr != null){
        StringBuilder sb = new StringBuilder("[");
        for (int i = 0; i < arr.length; i++) {
            if (i != arr.length-1){
                sb.append(arr[i]).append(" ");//不应该sb.append(arr[i]+" ");
            }else{
                sb.append(arr[i]);
            }
            //以上两步可以成为一步骤 sb.append(arr[i]).append(i == arr.length - 1 ? "" :", ")

        }
        sb.append("]");
        System.out.println(sb);

    }else{
        System.out.println(arr);
    }