通过反射获取枚举的值 [英] Get value of enum by reflection

问题描述

我有一个这样声明的枚举：

I have an enum declared like this:

public enum Mode{
  RUNNING("SytemRunning"),
  STOPPED("SystemStopped"),
  IDLE("tmpIdle");

  public static String key;

  private Mode(String key){
    this.key = key;
  }
}

现在，我想拿出钥匙（SystemRunning ，通过反射对此枚举进行枚举：

Now, I want to get out the keys(SystemRunning, SystemStopped, tmpIdle) for this enum by reflection:

Class<?> c = Class.forName("Mode");
Object[] objects = c.getEnumConstants();
// now this is not what I want, but almost
for(Object obj : objects){
  System.out.println("value : " + obj);
}

输出为：
正在运行
已停止
IDLE

the output is: RUNNING STOPPED IDLE

但是，我想使用Strings SystemRunning，tmpIdle等。

However, I'd like to have the Strings SystemRunning, tmpIdle etc..

谢谢

推荐答案

首先，您需要创建密钥非静态变量。

Firstly, you need to make your key a non-static variable.

private String key; // I made it private on purpose

然后您需要在枚举中添加getter方法，返回 key

Then you need to add a getter method in your enum which will return the key

public String getKey() {
    return key;
}

，然后将您的更改为

and then change your for loop to something like this.

for (Object obj : objects) {
    Class<?> clzz = obj.getClass();
    Method method = clzz.getDeclaredMethod("getKey");
    String val = (String) method.invoke(obj);
    System.out.println("value : " + val); // prints SytemRunning, SystemStopped and tmpIdle
}

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