Java常量示例（创建只有常量的java文件） [英] Java constant examples (Create a java file having only constants)

问题描述

声明只有常量的java文件的最佳做法是什么？

What is the best practice to declare a java file having only constant?

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

OR

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

推荐答案

两者都没有。使用常量类为常量将它们声明为 public static final ，并在必要时静态导入所有常量。

Neither one. Use final class for Constants declare them as public static final and static import all constants wherever necessary.

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);
        }
}

请参阅wiki链接： http://en.wikipedia.org/wiki/Constant_interface

See wiki link : http://en.wikipedia.org/wiki/Constant_interface

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