java中enum的用法示例

例1：

代码：

import java.util.EnumSet;

enum WeekDay {
    SUN, MON, TUE, WED, THT, FRI, SAT
}
public class Test_Enum {
        public static void main(String[] args) {
            EnumSet<WeekDay> week = EnumSet.noneOf(WeekDay.class);
            week.add(WeekDay.MON);
            System.out.println("EnumSet中的元素：" + week);
            week.remove(WeekDay.MON);
            System.out.println("EnumSet中的元素：" + week);

            week.addAll(EnumSet.complementOf(week));
            System.out.println("EnumSet中的元素：" + week);

            week.removeAll(EnumSet.range(WeekDay.FRI, WeekDay.SAT));
            System.out.println("EnumSet中的元素：" + week);
        }
}

输出：

EnumSet中的元素：[MON]
EnumSet中的元素：[]
EnumSet中的元素：[SUN, MON, TUE, WED, THT, FRI, SAT]
EnumSet中的元素：[SUN, MON, TUE, WED, THT]

例2：

结构：

代码：

ColorType

package Test_Enum;


public  enum ColorType {

    RED("1","红色"), YELLOW("2","黄色"), GREEN("3","绿色");

    private String code;
    private String value;

    ColorType(String code, String value) {
        this.code = code;
        this.value = value;
    }

    public static String getValueByCode(String code) {
        ColorType[] values = ColorType.values();
        for (ColorType type : values) {
            if (type.code.equalsIgnoreCase(code)) {
                return type.value;
            }
        }
        return null;
    }

    @Override
    public String toString() {
        return "ColorType{" +
                "code='" + code + '\'' +
                ", value='" + value + '\'' +
                '}';
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public static String getCodeByValue(String value) {
        ColorType[] values = ColorType.values();
        for (ColorType type : values) {
            if (type.value.equalsIgnoreCase(value)) {
                return type.code;
            }
        }
        return null;
    }
}

WeekDay

package Test_Enum;

public  enum WeekDay {
    SUN, MON, TUE, WED, THT, FRI, SAT
}

Test_Enum

package Test_Enum;


import static Test_Enum.ColorType.GREEN;
import static Test_Enum.WeekDay.SUN;
import static Test_Enum.WeekDay.WED;

public class Test_Enum {
    public static void main(String[] args) {
        System.out.println(GREEN.getCode());
        System.out.println(GREEN.getValue());
        System.out.println(GREEN);

        String code = ColorType.getCodeByValue("黄色");
        System.out.println("code=" + code);

        String value = ColorType.getValueByCode("1");
        System.out.println("value=" + value);
//==========================================================
        System.out.println(WED);
        WeekDay weekday = SUN;
        switch (weekday) {
            case SUN:
                System.out.println("sunday");;
                break;
        }
    }
}

输出

3
绿色
ColorType{code='3', value='绿色'}
code=2
value=红色
WED
sunday

相关资料：

• https://blog.youkuaiyun.com/howard789/article/details/81513803
• https://blog.youkuaiyun.com/echizao1839/article/details/80890490