C# => JAVA：在声明时填充静态 ArrayList。可能的？
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C# => JAVA: Filling a static ArrayList on declaration. Possible?
提问by Peterdk
In my C# project I have a static List that gets filled immediately when declared.
在我的 C# 项目中，我有一个静态列表，在声明时会立即填充。
private static List<String> inputs = new List<String>()
{ "Foo", "Bar", "Foo2", "Bar2"};
How would I do this in Java using the ArrayList?
我将如何使用 ArrayList 在 Java 中做到这一点？
I need to be able to access the values without creating a instance of the class. Is it possible?
我需要能够在不创建类的实例的情况下访问这些值。是否可以？
回答by Clint
You can use Double Brace Initialization. It looks like:
您可以使用双括号初始化。看起来像：
private static List<String> inputs = new ArrayList<String>()
{{ add("Foo");
add("Bar");
add("Foo2");
add("Bar2");
}};
回答by MAK
I don't understand what you mean by
我不明白你的意思
able to access the values without creating a instance of the class
能够在不创建类的实例的情况下访问这些值
but the following snippet of code in Java has pretty much the same effect in Java as yours:
但是以下 Java 中的代码片段在 Java 中的效果与您的几乎相同：
private static List<String> inputs = Arrays.asList("Foo", "Bar", "Foo2", "Bar2");
回答by Jason Nichols
You can make static calls by enclosing them within static{} brackets like such:
您可以通过将它们括在静态{} 括号中来进行静态调用，如下所示：
private static final List<String> inputs = new ArrayList<String>();
static {
inputs.add("Foo");
inputs.add("Bar");
inputs.add("Foo2");
inputs.add("Bar2");
}
回答by jdmichal
Do you need this to be an ArrayListspecifically, or just a list?
你需要这是一个ArrayList具体的，还是只是一个列表？
Former:
前任的：
private static java.util.List<String> inputs = new java.util.ArrayList<String>(
java.util.Arrays.<String>asList("Foo", "Bar", "Foo2", "Bar2"));
Latter:
后者：
private static java.util.List<String> inputs =
java.util.Arrays.<String>asList("Foo", "Bar", "Foo2", "Bar2");
回答by Kevin Bourrillion
You may enjoy ImmutableListfrom Guava:
你可以ImmutableList从番石榴中享受：
ImmutableList<String> inputs = ImmutableList.of("Foo", "Bar", "Foo2", "Bar2");
ImmutableList<String> inputs = ImmutableList.of("Foo", "Bar", "Foo2", "Bar2");
The first half of this youtube videodiscusses the immutable collections in great detail.
这个 youtube 视频的前半部分非常详细地讨论了不可变集合。
