单行内的初始化列表

Question

I am using multimap as shown below but as shown but the issue with this that first i am adding the contents in listand then associating it with the key, can I do it in a single line itself.

Map<Integer, List<String>> multimap = new HashMap<Integer, List<String>>();
List<String> someList = new ArrayList<String>();
someList.add("abc");
someList.add("def");
someList.add("ght");
multimap.put(1, someList);

that is adding list contents where I am eneterting the key. something like

 multimap.put(1, // adding the list in a single line here itslef );

Answer 1

它不是很漂亮，但是您可以按照以下方式进行操作

multimap.put(1, new ArrayList<String>(Arrays.asList("abc", "def", "ght")));

Answer 2

尝试以下代码：

multimap.put(1, Arrays.asList(new String[]{"abc","def","ght"}));

Answer 3

你可以用

List<String> someList = Arrays.asList("abc", "def", "ght");

Answer 4

You are implementing Guavas Multimap by hand, I recommend you to look at the Guava solution.

Multimap<Integer, String> multimap = HashMultimap.create();
multimap.putAll(1, Lists.newArrayList("a", "b", "c"));

This article nicely explains some of the advantages of the Guava Multimap implementation.

While we're at it, guava also provides a solution to initialize lists on one line ( javadoc ):

Lists.newArrayList("a", "b", "c");

Answer 5

Map<Integer, List<String>> multimap = new HashMap<Integer, List<String>>();

然后

multimap.put(1, new ArrayList<String>(Arrays.asList("abc", "def", "ght")));

Answer 6

Map<Integer, List<String>> singletonMap = Collections.singletonMap(Integer.valueOf(1), Arrays.asList("abc", "dd", "dde"));

Answer 7

multimap.put(1,new ArrayList<String>(Arrays.asList("element","element")));