一次向 Java 5 HashSet 添加多个字段？
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Add multiple fields to Java 5 HashSet at once?
提问by cmcculloh
Is there a better way to do this so I don't have to have 50 ".add()"s in there? Like a comma separated list or something (like JavaScript arrays).
有没有更好的方法来做到这一点，所以我不必在那里有 50 个“.add()”？像逗号分隔的列表或其他东西（如 JavaScript 数组）。
private static final Set<String> validStates = new HashSet<String>();
validStates.add("AL");
validStates.add("AK");
validStates.add("AZ");
validStates.add("AR");
validStates.add("CA");
validStates.add("CO");
validStates.add("CT");
validStates.add("DE");
validStates.add("DC");
validStates.add("FL");
validStates.add("GA");
validStates.add("HI");
validStates.add("ID");
validStates.add("IL");
validStates.add("IN");
validStates.add("IA");
validStates.add("KS");
validStates.add("KY");
validStates.add("LA");
validStates.add("ME");
validStates.add("MD");
validStates.add("MA");
validStates.add("MI");
validStates.add("MN");
validStates.add("MS");
validStates.add("MO");
validStates.add("MT");
validStates.add("NE");
validStates.add("NV");
validStates.add("NH");
validStates.add("NJ");
validStates.add("NM");
validStates.add("NY");
validStates.add("NC");
validStates.add("ND");
validStates.add("OH");
validStates.add("OK");
validStates.add("OR");
validStates.add("PA");
validStates.add("RI");
validStates.add("SC");
validStates.add("SD");
validStates.add("TN");
validStates.add("TX");
validStates.add("UT");
validStates.add("VT");
validStates.add("VA");
validStates.add("WA");
validStates.add("WV");
validStates.add("WI");
validStates.add("WY");
Something like:
就像是：
validStates.add("AL", "AK", "...");
回答by BalusC
The HashSethas a constructor taking a Collection. The Arrays#asList()takes arguments as varargsand returns a List(which is a Collection). So, you could do it as follows:
该HashSet有一个构造服用Collection。所述Arrays#asList()接受参数作为可变参数，并返回List（这是一个Collection）。所以，你可以这样做：
validStates = new HashSet<String>(Arrays.asList("AL", "AK", ".."));
It makes however more sense to have them in some properties file or in a DB which you load by one or two lines of code so that you don't need to hardcode them all in Java.
然而，将它们放在一些属性文件或数据库中更有意义，您可以通过一两行代码加载它们，这样您就不需要在 Java 中对它们全部进行硬编码。
If you were on Java 8+, you could just use Stream#of().
如果您使用的是 Java 8+，则可以使用Stream#of().
validStates = Stream.of("AK", "AL", "..").collect(Collectors.toSet());
回答by skaffman
If you fancy using the excellent Google Guava library, you can use:
如果您喜欢使用优秀的Google Guava 库，您可以使用：
Set<String> validStates = Sets.newHashSet("AL", "AK", "...");
回答by DHall
You could have a static String[]with all the states, then iterate over the array:
你可以有一个String[]包含所有状态的静态，然后遍历数组：
String states[] = {"AL","AK","AZ","AR",...etc...};
for (String currState : states) {
validStates.add(currState);
}
I don't remember if this "foreach" construct came in 1.5 or 1.6....
我不记得这个“foreach”构造是在 1.5 还是 1.6 中出现的....
回答by Snehal
HashSet<String> hs = Sets.newHashSet("abc","xyz");
