import java.util.*; public class ListToHashMapExample { public static void main(String[] args) { List<Person> personList = Arrays.asList( new Person("Alice", 25), new Person("Bob", 30), new Person("Charlie", 35) ); Map<String, Person> personMap = new HashMap<...
importjava.util.*;publicclassListToLinkedHashMap{publicstaticvoidmain(String[]args){List<String>list=newArrayList<>();list.add("A");list.add("B");list.add("C");Map<Integer,String>linkedHashMap=newLinkedHashMap<>();for(inti=0;i<list.size();i++){linkedHashMap.put(i,list.get(i));...
接下来,使用Stream API将List<User>转换为HashMap<Integer, String>: 代码语言:javascript 复制 importjava.util.List;importjava.util.HashMap;importjava.util.stream.Collectors;publicclassListToMapExample{publicstaticvoidmain(String[]args){// 创建一个User对象的列表List<User>userList=List.of(newUser(1,"A...
Integer>convertListToLinkedHashMap(List<String>list){LinkedHashMap<String,Integer>linkedHashMap=newLinkedHashMap<>();Stream<String>stream=list.stream();stream.forEach(item->{linkedHashMap.put(item,list.indexOf(item));
List locations = Arrays.asList("us:5423", "us:6321", "CA:1326", "AU:5631"); Map> map = locations.stream() .map(DELIMITER::split) // 使用Pattern分割字符串数组,获取键值对列表。 .collect(Collectors.groupingBy(arr -> arr, // 根据键值对列表中的第一个元素分组。
System.out.println();//用迭代器遍历Iterator<String> iterator =list.listIterator();while(iterator.hasNext()){ System.out.print(iterator.next()); } } } 2、遍历HashMap importjava.util.HashMap;importjava.util.Iterator;importjava.util.Map;importjava.util.Set;publicclassMapIteratorDemo1 {publicsta...
Map<Long, User> maps = new HashMap<>(); for (User user : userList) { maps.put(user.getId(), user); } 方法2:使用 guava Map<Long, User> maps = Maps.uniqueIndex(userList, new Function<User, Long>() { @Override public Long apply(User user) { ...
}Map<Integer,String> map=newHashMap<>(); map.put(1,"a"); map.put(2,"b"); map.put(3,"c");// key 转 ListList<Integer> keyList=newArrayList<>(map.keySet());List<Integer> keyList2=map.keySet().stream().collect(Collectors.toList()); ...
public staticMap> toMapList(Listlist, KeyFunckeyFunc) { Map> result = new HashMap<>(); for (V item: list) { K key = keyFunc.getKey(item); if (!result.containsKey(key)) { result.put(key, new ArrayList<>()); } result.get(key).add(item); ...
步骤1: 将List转换为Stream List<String>list=Arrays.asList("A","B","C","D");Stream<String>stream=list.stream(); 1. 2. 步骤2: 使用Collectors.toMap()方法创建LinkedHashMap Map<String,String>linkedHashMap=stream.collect(Collectors.toMap(Function.identity(),Function.identity(),(e1,e2)->e1,...