Java 中 HashMap 的字面声明
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Literal declaration of HashMap in Java
提问by Shahid Thaika
In JavaScript, you can declare all the keys and value combinations for a JSONobject in one go as follows...
在 中JavaScript，您可以JSON一次性声明一个对象的所有键和值组合，如下所示...
var myJSON = {
'key1' : 'value 1',
'key2' : 'value 2',
'key3' : 'value 3',
'key4' : 'value 4',
'key5' : 'value 5',
'key6' : 'value 6'
};
I was wondering whether we can do something similar in Javafor HashMaps.
我想知道我们是否可以在Javafor 中做类似的事情HashMaps。
HashMap<String, String> map = new HashMap<String, String>(
"Key 1", "Value 1",
"Key 2", "Value 2",
"Key 3", "Value 3"
);
Basically, I need this as a one time read only thing as Config for the other parts of my code. I searched and tried a few solutions, but was not able to make them work. Or is there a better approach that I can do?
基本上，我需要将它作为一次性只读的东西作为我代码其他部分的配置。我搜索并尝试了一些解决方案，但无法使它们起作用。或者有没有更好的方法我可以做？
回答by Suresh Atta
Though {{(double brace) is an anti pattern, something like this you can write
虽然{{（双括号）是一种反模式，但你可以这样写
HashMap<String, String> map = new HashMap<String, String>(){{
put("Key 1", "Value 1");
put("Key 2", "Value 2");
put("Key 3", "Value 3");
}};
Edit :
编辑 ：
If you are looking for a better way to put elements, iterate over your json and put key values in a loop.
如果您正在寻找一种更好的方法来放置元素，请遍历您的 json 并将键值放入循环中。
回答by assylias
There is no concept of map literals in Java but you can easily write a utility method to achieve something similar. See this implementationfor example. You can then initialise a map (using static imports):
Java 中没有映射字面量的概念，但您可以轻松编写一个实用程序方法来实现类似的功能。例如，请参阅此实现。然后您可以初始化地图（使用静态导入）：
Map<String, String> map = map("k1", "v1", "k2", "v2");
An alternative is to use the "double brace initialisation" syntax but it creates an anonymous inner class which is not necessarily a good idea.
另一种方法是使用“双括号初始化”语法，但它创建了一个匿名内部类，这不一定是一个好主意。
