问题
I want to fill an ArrayList with these characters +,-,*,^ etc. How can I do this without having to add every character with arrayList.add()?
回答1:
Collections.addAll is what you want.
Collections.addAll(myArrayList, '+', '-', '*', '^');
Another option is to pass the list into the constructor using Arrays.asList like this:
List<Character> myArrayList = new ArrayList<Character>(Arrays.asList('+', '-', '*', '^'));
If, however, you are good with the arrayList being fixed-length, you can go with the creation as simple as list = Arrays.asList(...). Arrays.asList specification states that it returns a fixed-length list which acts as a bridge to the passed array, which could be not what you need.
回答2:
Assuming you have an ArrayList that contains characters, you could do this:
List<Character> list = new ArrayList<Character>();
list.addAll(Arrays.asList('+', '-', '*', '^'));
回答3:
You can use Google guava as such:
ImmutableList<char> dirs = ImmutableList.of('+', '-', '*', '^');
回答4:
You can use the asList method with varargs to do this in one line:
java.util.Arrays.asList('+', '-', '*', '^');
If the list does not need to be modified further then this would already be enough. Otherwise you can pass it to the ArrayList constructor to create a mutable list:
new ArrayList(Arrays.asList('+', '-', '*', '^'));
回答5:
May be this helps
List<String> l = Arrays.asList("+","-");
回答6:
Use Arrays class in Java which will return you an ArrayList :
final List<String> characters = Arrays.asList("+","-");
You will need a bit more work if you need a List<Character>.
来源：https://stackoverflow.com/questions/8985432/how-to-use-arraylist-addall