Java 常量示例(创建一个只有常量的 java 文件)

Question

声明只有常量的 java 文件的最佳做法是什么？

public interface DeclareConstants
{
    String constant = "Test";
}

或

public abstract class DeclareConstants
{
    public static final String constant = "Test";
}

Answer 1

一个都没有。使用 final class for Constants 将它们声明为 public static final 并在必要时静态导入所有常量。

public final class Constants {

    private Constants() {
            // restrict instantiation
    }

    public static final double PI = 3.14159;
    public static final double PLANCK_CONSTANT = 6.62606896e-34;
}

用法:

import static Constants.PLANCK_CONSTANT;
import static Constants.PI;//import static Constants.*;

public class Calculations {

        public double getReducedPlanckConstant() {
                return PLANCK_CONSTANT / (2 * PI);
        }
}

查看维基链接:http://en.wikipedia.org/wiki/Constant_interface