使用预定义值填充hashmap（java） [英] Populating a hashmap with predefined values (java)

问题描述

我遇到了一个我以前没有处理过的问题。我正在为java中的数据库写一个补丁，基本上是转换某些行中存储的数据。为了做到这一点，我有一个转换表，告诉我什么值成了什么。

例如，如果我读了RC，AC，GH - >将值更新为T1。 （这些只是随机的例子，它基本上是将一个字符串转换为另一个字符串。）

我需要一种存储这些转换的好方法。我正在考虑一个hashmap：
KEY，VALUE：（RC，T1）（AC，T1）（GH，T1）等等。

现在，有几十个这样的。修补程序初始化时填充此散列映射的干净方式是什么？

解决方案

我将在设置HashMap的同时进行初始化

例如

  private static final Map< String，String> m = new HashMap< String，String>（）{{
 put（RC，T1）; 
 put（AC，T1）; 
}}; 
  

然后你就可以确保代码中的所有内容一起设置。

我认为@Nambari是一个很好的观点，尽管可能有值作为列表而不仅仅是一个字符串。然而，这会交换您的密钥和值。

eg

  private static final Map< String，List< String>> m = new HashMap< String，List< String>>（）{{
 put（T1，Arrays.asList（RC，AC）; 
}}; 
  

I've run into a problem I haven't had to deal with before. I'm writing a patch for a database in java that's basically converting data stored in certain rows. In order to do this I have a conversion table that tells me what values become what.

Example, if I read in either "RC", "AC", "GH" -> Update the value to "T1". (These are just random examples, it's basically converting one string to another.)

I need a good way of storing these conversions. I was thinking a hashmap: KEY,VALUE: (RC,T1) (AC,T1) (GH,T1) and so on and so on.

Now, there's dozens and dozens of these. What's a good clean way of populating this hashmap when the patch initializes?

解决方案

I would do the initialisation while setting up the HashMap

For example

private static final Map<String, String> m = new HashMap<String, String>() {{
    put("RC", "T1");
    put("AC", "T1");
}};

Then you wuld make sure that everything is set up together in your code.

I think @Nambari makes a good point though with perhaps having the value as a list rather than just a string. This does then swap your keys and values though.

eg

 private static final Map<String, List<String>> m = new HashMap<String, List<String>>() {{
    put("T1", Arrays.asList("RC", "AC");
}};

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