Java - 不知道如何调用公共(public)枚举类

Question

我对 Java 有点陌生......

这是我想要实现的 Java 源代码。

首先我定义一个公共(public)枚举类，如下所示:

public enum Day {
SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
THURSDAY, FRIDAY, SATURDAY 
}

现在我创建一个这样的类:

import java.time.*;

public class EnumTest {
Day day;

public EnumTest(Day day) {
    this.day = day;
}

public void tellItLikeItIs() {
    switch (day) {
        case MONDAY:
            System.out.println("Mondays are bad.");
            break;

        case FRIDAY:
            System.out.println("Fridays are better.");
            break;

        case SATURDAY: case SUNDAY:
            System.out.println("Weekends are best.");
            break;

        default:
            System.out.println("Midweek days are so-so.");
            break;
    }
}

public static void main(String[] args) {
    EnumTest firstDay = new EnumTest(Day.MONDAY);
    firstDay.tellItLikeItIs();
    EnumTest thirdDay = new EnumTest(Day.WEDNESDAY);
    thirdDay.tellItLikeItIs();
    EnumTest fifthDay = new EnumTest(Day.FRIDAY);
    fifthDay.tellItLikeItIs();
    EnumTest sixthDay = new EnumTest(Day.SATURDAY);
    sixthDay.tellItLikeItIs();
    EnumTest seventhDay = new EnumTest(Day.SUNDAY);
    seventhDay.tellItLikeItIs();
}
}

当我编译 EnumTest 类时，我收到此错误:

C:\java>javac EnumTest.java
EnumTest.java:4: error: class Day is public, should be declared in a file named
Day.java
public enum Day {
   ^
1 error

你能帮我吗？谢谢梅尔

Answer 1

您的代码看起来不错，出现错误是因为您在同一文件下保存两个公共(public)类(枚举也是类)。

创建两个单独的文件并将枚举写入其中，并将其另存为Day.java。以及带有 class EnumTest 的其他文件并将其另存为 EnumTest.java不要忘记将它们放在同一个包下。否则，您将必须使用 import packagename.Day

导入枚举

或者

更简单的方法，从 Enum 中删除 public

     enum Day {
      SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
      THURSDAY, FRIDAY, SATURDAY 
      }

现在你的代码将编译