Java：更改“VK_UP”到KeyEvent.VK_UP [英] Java: change "VK_UP" to KeyEvent.VK_UP

问题描述

我需要将>VK_UP（或简单地UP）等文本更改/解析为< Java中的code> KeyEvent.VK_UP 常量。我不想使用数字 38 ，因为它会保存在 .txt 配置文件中，所以任何人都可以重写它最好的解决办法是有这个散列图：

  HashMap< String，Integer> keyConstant; 
  

其中key是名称（VK_UP 38 ）。

现在的问题是：我怎样才能得到这张地图不需要花费一整晚的时间来手工创建它？

解决方案

您可以使用反射。

以下各行中的内容应该起作用，例外处理：

  public static int parseKeycode（String keycode ）{
 //假设keycode的格式为VK_ {KEY} 
 Class keys = KeyEvent.class; //这是存储所有密钥的地方。 
 Field key = keys.getDeclaredField（keycode）; //按名称获取字段。 
 int keycode = key.get（null）; // VK_ {KEY}字段是静态的，所以我们传递'null'作为反射访问器的实例。 
返回键码; 
} 
  

或者，您可以使用简单的单行程式：

  KeyEvent.class.getDeclaredField（keycode）.get（null）; 
  

I need to change/parse text like "VK_UP" (or simply "UP") to the KeyEvent.VK_UP constant in Java. I dont want to use the number 38 instead since it will be saved in a .txt config file so anybody could rewrite it.

Best solution would be to have this hashmap:

HashMap<String, Integer> keyConstant;

Where key would be the name ("VK_UP") and value would be key code (38).

Now the question is: How can I get this map without spending all evening creating it manually?

解决方案

You can use reflection.

Something among the lines of the following should work, sans exception handling:

public static int parseKeycode(String keycode) {
    // We assume keycode is in the format VK_{KEY}
    Class keys = KeyEvent.class; // This is where all the keys are stored.
    Field key = keys.getDeclaredField(keycode); // Get the field by name.
    int keycode = key.get(null); // The VK_{KEY} fields are static, so we pass 'null' as the reflection accessor's instance.
    return keycode;
}

Alternatively, you could use a simple one-liner:

KeyEvent.class.getDeclaredField(keycode).get(null);

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