Java 基本类型数组、包装类数组、集合之间的相互转换（以及遍历方法）
import java.util.*;import java.util.stream.Collectors;import static java.util.Arrays.*;public class ZhuanHuan{ public static void main(String[] args) { //数组: int[] int[] arrayInt = new int[]{1,2,3,4,5,6}; printElement(arrayInt); //原生数组转包装类数组: int[] 2 Integer[] Integer[] arrayInter = Arrays.stream(arrayInt).boxed().toArray(Integer[]::new); printElement(arrayInter); //*包装类数组转List/ArrayList: Integer[] 2 List<Integer> List<Integer> listInter = Arrays.asList(arrayInter); printElement(listInter); //*List/ArrayList转包装类数组: List<Integer> 2 Integer[] Integer[] arrayInter2 = listInter.toArray(new Integer[listInter.size()]); printElement(arrayInter2); //包装类数组转原生数组: Integer[] 2 int[] int[] arrayInt2 = Arrays.stream(arrayInter2).mapToInt(Integer::valueOf).toArray(); printElement(arrayInt2); //原生数组转List/ArrayList: int[] 2 List<Integer> List<Integer> listInter2 = Arrays.stream(arrayInt2).boxed().collect(Collectors.toList()); printElement(listInter2); //List/ArrayList转原生数组： List<Integer> 2 int[] int[] arrayInt3 = listInter2.stream().mapToInt(Integer::valueOf).toArray(); printElement(arrayInt3); } //原生数组遍历输出 private static void printElement(int[] arr){ for(int i=0;i<arr.length;i++){ System.out.println(arr[i]); } } //包装类数组遍历输出 private static void printElement(Integer[] arr){ for(int i=0;i<arr.length;i++){ System.out.println(arr[i]); } } //List遍历输出 private static void printElement(List list){ Iterator iter = list.iterator(); while(iter.hasNext()){ System.out.println(iter.next()); } }}