编写一个数组的工具类

package com.zyf.day16;
/**
* 需求:编写一个数组的工具类
* @author root
*
*/
class MyArrays{
//元素反转
public <T>void reverse(T[] arr){
for(int startIndex = 0,endIndex = arr.length -1;startIndex < endIndex;startIndex++,endIndex--){
T temp = arr[startIndex];
arr[startIndex] = arr[endIndex];
arr[endIndex] = temp;
}
}

public <T>String toString(T[] arr){
StringBuilder sb = new StringBuilder();
for(int i = 0;i < arr.length;i++){
if(i==0){
sb.append("[" + arr[i] + ",");
}else if(i == arr.length -1){
sb.append(arr[i] + "]");
}else{
sb.append(arr[i] + ",");
}
}
return sb.toString();
}
}
public class demo3 {
public static void main(String[] args){
Integer[] arr = {10,12,14,19};
//创建了数组的工具类对象
MyArrays arrTool = new MyArrays();

arrTool.reverse(arr);
System.out.println(arrTool.toString(arr));
}

}