java中多种方法实现数组转list，数组转set

Love The Way You Lie 2023-10-01 15:58 37阅读 0赞

1. 数组->list

1.1 Arrays.asList()

tips: 该方法返回的是基于数组的List视图（List view）。对Arrays.asList()返回的List进行添加、删除操作会报错，可以使用set(修改)方法

  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa"};
  3. List strList = Arrays.asList(strArray);
  5. System.out.println(strList);
  6. //strArray: [isy, mi, ka, sa]
1.2 Collections.addAll()

tips: 该方法实际上是将数组的内容复制到ArrayList中

  1. List strList = new ArrayList();
  2. String[] strArray = {
  3.     "isy", "mi", "ka", "sa"};
  4. Collections.addAll(strList, assstrArrayet);
  6. System.out.println(strList);
  7. //strArray: [isy, mi, ka, sa]
1.3 Java 8 新特性
1.3.1.Stream.of()
  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa"};
  3. List strList = Stream.of(strArray).collect(Collectors.toList());
  5. System.out.println(strList);
  6. //strArray: [isy, mi, ka, sa]
1.3.2 将数组转为stream (可以做更灵活的其他操作)
  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa"};
  3. List strList = Arrays.stream(strArray).collect(Collectors.toList());
  5. System.out.println(strList);
  6. //strArray: [isy, mi, ka, sa]

2. list->数组

  1. list.toArray()

3. 数组->set

3.1. Arrays.asList()
  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa", "sa"};
  3. Set<T> strSet = new HashSet<>(Arrays.asList(strArray));
  5. System.out.println(strSet);
  6. //strSet: [isy, mi, ka, sa]
3.2. Collections.addAll()

tips: 该方法实际上是将数组的内容复制到set中

  1. Set<T> strSet = new HashSet<T>();
  2. String[] strArray = {
  3.     "isy", "mi", "ka", "sa", "sa"};
  4. Collections.addAll(strSet, strArray);
  6. System.out.println(strSet);
  7. //strSet: [isy, mi, ka, sa]
3.3. Java 8 新特性
3.3.1 将数组转为stream (可以做更灵活的其他操作)
  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa", "sa"};
  3. Set<String> strSet = Arrays.stream(strArray).collect(Collectors.toSet());
  5. System.out.println(strSet);
  6. //strSet: [isy, mi, ka, sa]
3.4. Java 9 新特性
3.4.1 前提：不可修改
  1. String[] strArray = {
  2.     "isy", "mi", "ka", "sa", "sa"};
  3. Set<T> mySet = Set.of(strArray);
  5. System.out.println(strSet);
  6. //strSet: [isy, mi, ka, sa]

老是完，整理记录一下

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