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 24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

String[] strArray = {
        "isy", "mi", "ka", "sa"};
    List strList = Arrays.asList(strArray);
    
    System.out.println(strList);
    //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

List strList = new ArrayList();
    String[] strArray = {
        "isy", "mi", "ka", "sa"};
    Collections.addAll(strList, assstrArrayet);
    
    System.out.println(strList);
    //strArray: [isy, mi, ka, sa]

##### 1.3 Java 8 新特性 #####

###### 1.3.1.Stream.of() ######

String[] strArray = {
        "isy", "mi", "ka", "sa"};
    List strList = Stream.of(strArray).collect(Collectors.toList());
    
    System.out.println(strList);
    //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) ######

String[] strArray = {
        "isy", "mi", "ka", "sa"};
    List strList = Arrays.stream(strArray).collect(Collectors.toList());
    
    System.out.println(strList);
    //strArray: [isy, mi, ka, sa]

### **2. list->数组** ###

list.toArray()

### **3. 数组->set** ###

##### 3.1. Arrays.asList() #####

String[] strArray = {
        "isy", "mi", "ka", "sa", "sa"};
    Set<T> strSet = new HashSet<>(Arrays.asList(strArray));
    
    System.out.println(strSet);
    //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

Set<T> strSet = new HashSet<T>();
    String[] strArray = {
        "isy", "mi", "ka", "sa", "sa"};
    Collections.addAll(strSet, strArray);
    
    System.out.println(strSet);
    //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) ######

String[] strArray = {
        "isy", "mi", "ka", "sa", "sa"};
    Set<String> strSet = Arrays.stream(strArray).collect(Collectors.toSet());
    
    System.out.println(strSet);
    //strSet: [isy, mi, ka, sa]

##### 3.4. Java 9 新特性 #####

###### 3.4.1 前提：不可修改 ######

String[] strArray = {
        "isy", "mi", "ka", "sa", "sa"};
    Set<T> mySet = Set.of(strArray);
    
    System.out.println(strSet);
    //strSet: [isy, mi, ka, sa]

老是完，整理记录一下