List数组:存储List的数组,即:数组中的元素是:List;
数组List:存储数组的List,即:List中的数据是类型的数组;
测试案例:
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;/** List<T>数组,数组List<T>* */public class day15 {public static void main(String[] args) {List<Map<String,Object>> list = new ArrayList<>();Map<String,Object> map1 = new HashMap<>();map1.put("region","西安");map1.put("num",1.0);map1.put("count",1);list.add(map1);List<Map<String,Object>> list2 = new ArrayList<>();Map<String,Object> map2 = new HashMap<>();map2.put("region","武汉");map2.put("num",1.0);map2.put("count",2);list2.add(map2);List<Map<String,Object>> list3 = new ArrayList<>();Map<String,Object> map3 = new HashMap<>();map3.put("region","苏州");map3.put("num",1.0);map3.put("count",3);list3.add(map3);// List<T>数组:存储List<T>的数组,即数组中的元素是:List<T>// 用法1:List[] obj = {list,list2,list3};for (int i = 0; i < obj.length; i++) {System.out.println("List<T>数组:"+obj[i]);}System.out.println("--------------------------");// 用法2:List[] s = new List[3]; // 先声明长度:必须大于零;长度可通过计算得出;s[0] = list;s[1] = list2;s[2] = list3;for (int i = 0; i < s.length; i++) {System.out.println("List<T>数组:"+s[i]);}System.out.println("--------------------------");// 数组List<T>:存储数组的List<T>,即:List中的数据是<T>类型的数组;List<int[]> list4 = new ArrayList<>();int[] arr1 = {1,2,3};int[] arr2 = {4,5,6};list4.add(arr1);list4.add(arr2);for (int i = 0; i < list4.size(); i++) {int[] arr = list4.get(i);for (int j = 0; j < arr.length; j++) {System.out.println("数组List<T>:"+arr[j]);}}}
}
测试输出:
List<T>数组:[{num=1.0, count=1, region=西安}]
List<T>数组:[{num=1.0, count=2, region=武汉}]
List<T>数组:[{num=1.0, count=3, region=苏州}]
--------------------------
List<T>数组:[{num=1.0, count=1, region=西安}]
List<T>数组:[{num=1.0, count=2, region=武汉}]
List<T>数组:[{num=1.0, count=3, region=苏州}]
--------------------------
数组List<T>:1
数组List<T>:2
数组List<T>:3
数组List<T>:4
数组List<T>:5
数组List<T>:6