Java常量示例(创建只有常量的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";
}

要么

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

Answer 1

没有一个.使用final class for Constants声明它们,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);
        }
}

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

Answer 2

-创建一个Class带有public static final 字段的.

-然后您可以使用Class_Name.Field_Name.

-你可以声明classas final，这样就class 不能扩展（继承）和修改......