Java中关于枚举的7种用法

最新推荐文章于 2020-12-03 19:40:59 发布

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最新推荐文章于 2020-12-03 19:40:59 发布

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分类专栏： java 文章标签： java enum

本文链接：https://blog.youkuaiyun.com/qq_26761229/article/details/65444320

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本文深入探讨Java枚举的多种用途，包括定义、用作switch语句、添加自定义方法、覆盖toString方法、实现接口以及使用枚举集合。通过具体实例展示如何增强枚举的功能性和灵活性。

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记录

1.定义常量：

public enum Color {
    RED,ORANGE,YELLOW,GREEN,INDIGO,BLUE,PURPLE
}

2.用于switch：

enum Color {
    RED,ORANGE,YELLOW,GREEN,INDIGO,BLUE,PURPLE
}
public class Draw{
    Color c = Color.BLUE;
    public void draw(){
        switch(c){
        case RED:
            c = Color.RED;
            break;
        case ORANGE:
            c = Color.ORANGE;
            break;
        case YELLOW:
            c = Color.YELLOW;
            break;
        case GREEN:
            c = Color.GREEN;
            break;
        case INDIGO:
            c = Color.INDIGO;
            break;
        case BLUE:
            c = Color.BLUE;
            System.out.println("打印：" + Color.BLUE);
            break;
        case PURPLE:
            c = Color.PURPLE;
            break;
        }
    }
}

3.在枚举中添加新方法：

public enum Color {
    RED(1,"红"),
    ORANGE(2,"橙"),
    YELLOW(3,"黄"),
    GREEN(4,"绿"),
    INDIGO(5,"靛"),
    BLUE(6,"蓝"),
    PURPLE(7,"紫");
    //成员变量
    private int sequence;
    private String name;
    //构造方法
    private Color(int sequence, String name) {
        this.sequence = sequence;
        this.name = name;
    }
    //自定义方法
    public static String getColorName(int sequence){
        for (Color c : Color.values()) {
            if(c.getSequence() == sequence)
                return c.name;
        }
        return null;
    }
    //getter&setter
    public int getSequence() {
        return sequence;
    }
    public void setSequence(int sequence) {
        this.sequence = sequence;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

4.覆盖（重写）枚举的方法：

public enum Color {
    RED(1,"红"),
    ORANGE(2,"橙"),
    YELLOW(3,"黄"),
    GREEN(4,"绿"),
    INDIGO(5,"靛"),
    BLUE(6,"蓝"),
    PURPLE(7,"紫");
    //成员变量
    private int sequence;
    private String name;
    //构造方法
    private Color(int sequence, String name) {
        this.sequence = sequence;
        this.name = name;
    }
    //覆盖方法
    @Override
    public String toString() {
        return "顺序："+this.sequence+"_颜色名："+this.name;
    }
}

5.实现接口：

interface Action{
    void getDetail();
}
public enum Color implements Action{
    RED(1,"红"),
    ORANGE(2,"橙"),
    YELLOW(3,"黄"),
    GREEN(4,"绿"),
    INDIGO(5,"靛"),
    BLUE(6,"蓝"),
    PURPLE(7,"紫");
    //成员变量
    private int sequence;
    private String name;
    //构造方法
    private Color(int sequence, String name) {
        this.sequence = sequence;
        this.name = name;
    }
    @Override
    public void getDetail() {
        System.out.println("顺序："+this.sequence+"_颜色名："+this.name);
    }
}

6.使用接口组织枚举：

public interface Food {  
    enum Coffee implements Food{  
        BLACK_COFFEE,DECAF_COFFEE,LATTE,CAPPUCCINO  
    }  
    enum Dessert implements Food{  
        FRUIT, CAKE, GELATO  
    }  
}