Java 数组转成集合List三种方法
package com.list;import java.util.ArrayList;import java.util.Arrays;import java.util.List;/*** Java 数组转成集合List* @author luolei* @date 2月18日*/public class ArrayToList {public static void main(String[] args) {// TODO Auto-generated method stub//1、new arr[]//String[] arr = {"luo","lei","luolei"};//2、new arr[]/*String[] arr = new String[4];arr[0] = "luo";arr[1] = "lei";arr[2] = "luolei";*///3 、new arr[]String[] arr= new String[]{"luo","lei","luolei"};//1、拆分数组，逐个添加到ListList<String> list = new ArrayList<>(arr.length);for (String str : arr) {list.add(str);}System.out.println("list="+list); //list=[luo, lei, luolei]//2、addAll()List<String> list2 = new ArrayList<>();list2.addAll(list);list2.addAll(list);System.out.println("list2="+list2); //list2=[luo, lei, luolei, luo, lei, luolei]//3、Arrays.asList()List<String> list3= new ArrayList<>(Arrays.asList(arr));System.out.println("list3="+list3); //list3=[luo, lei, luolei]}}
数组、集合List、Set相互转换
package com.list;import java.util.ArrayList;import java.util.Arrays;import java.util.HashSet;import java.util.List;import java.util.Set;/*** 数组、List、Set相互转换* @author luolei* @date 2月18日*/public class ArrayAndListAndSetConvertion {public static void main(String[] args) {// TODO Auto-generated method stubString[] arr= new String[]{"luo","lei","luolei"};//数组转ListList<String> list= new ArrayList<>(Arrays.asList(arr));System.out.println("list="+list); //list=[luo, lei, luolei]//数组转SetSet<String> set= new HashSet<>(Arrays.asList(arr));System.out.println("set="+set); //set=[luolei, luo, lei]//List转SetSet<String> set2 = new HashSet<String>(list);System.out.println("set2="+set2); //set2=[luolei, luo, lei]//Set转ListList<String> list2 = new ArrayList<String>(set2);System.out.println("list2="+list2); //list2=[luolei, luo, lei]}}
