java - 从最终类中获取所有静态字符串值作为字符串数组或列表

Question

我有以下类(class):

 public final class FileNames
{

    private FileNames()
    {}

    public static final String A                     = "a.csv";
    public static final String B                     = "b.csv";
    public static final String C                     = "123.csv";
    ...
}

现在我想从上面的不同类中的某个位置获取所有字符串值。输出可以是字符串数组或ArrayList或任何其他集合。我使用的是jdk 1.7。不知道如何继续此操作，因为可以增加字符串列表，即可以添加“D”、“E”等.

Answer 1

反射(reflection)是你的 friend :)

public class Sample {

    public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException {
        Class<FileNames> clazz = FileNames.class;
        Field[] arr = clazz.getFields(); // Get all public fields of your class
        for (Field f : arr) {
            if (f.getType().equals(String.class)) { // check if field is a String
                String s = (String)f.get(null); // get value of each field
                // add s to a List
                System.out.println(s);
            }

        }
    }

}

 final class FileNames {

    private FileNames() {
    }

    public static final String A = "a.csv";
    public static final String B = "b.csv";
    public static final String C = "123.csv";

}

操作:

a.csv
b.csv
123.csv