FilesExpand file tree

 master

/

ConvertListAndArray.java

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

executable file

·

56 lines (43 loc) · 1.59 KB

 master

/

ConvertListAndArray.java

Copy path

Top

File metadata and controls

• Code
• Blame

executable file

·

56 lines (43 loc) · 1.59 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

package array;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

/**

* 测试 列表 和 数组的转换 关键是toArray方法

*/

public class ConvertListAndArray {

public static void main(String[] args) {

listToArray();

arrayToList();

}

private static void listToArray() {

List<Integer> list = new ArrayList<>();

for (int i = 0; i < 8; i++) {

list.add(i);

}

{

Integer[] intArray = new Integer[list.size()];

//todo 这个方法，如果数组长度和list长度相同，可以直接复制，不用方法返回值

list.toArray(intArray);

System.out.println("listToArray1:" + Arrays.toString(intArray));

Integer[] intArray2 = new Integer[0];

//todo 这里长度不同，传参的数组不会得到复制

list.toArray(intArray2);

System.out.println("listToArray2:" + Arrays.toString(intArray2));

}

{

Integer[] intArray = new Integer[0];

//取方法返回值的意思是，无论数组长度多少，方法返回的数组长度和list长度相同

intArray = list.toArray(intArray);

System.out.println("listToArray3:" + Arrays.toString(intArray));

}

{

//运行错误

//Integer[] integers = (Integer[]) list.toArray();

//System.out.println("listToArray4:" + Arrays.toString(integers));

}

}

private static void arrayToList() {

List<Integer> list = Arrays.asList(1, 2, 3, 4);

}

}