JAVA中数组(Array)、字符串(String)、集合(List、Set)相互转换

时间:2022-09-18 02:15:52

1、数组转List

String[] arr = new String[]{"A", "B", "C"};
List list = Arrays.asList(arr); //返回固定大小,不能做add和remove等操作

  

2、数组转Set

String[] arr= new String[]{"A", "B", "C"};
Set<String> set= new HashSet<>(Arrays.asList(arr)); //可以直接对set进行add和remove操作

  

3、List转数组

String[] arr= new String[]{"A", "B", "C"};
List list = Arrays.asList(arr);
Object[] result = list.toArray(); //使用toArray()方法

另外一种

<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>20.0</version>
</dependency>
byte[] bytes=Bytes.toArray(list);

4、List转Set

String[] arr= new String[]{"A", "B", "C"};
List list = Arrays.asList(arr);
Set result = new HashSet(list); //list转set

5、Set转数组

String[] arr= new String[]{"A", "B", "C"};
Set<String> set= new HashSet<>(Arrays.asList(arr));
Object[] result = set.toArray(); //使用toArray()方法

6、Set转List

String[] arr= new String[]{"A", "B", "C"};
Set<String> set= new HashSet(Arrays.asList(arr));
List<String> result = new ArrayList<>(set);