你知道Enum怎么比较大小吗

1、Enum实现Comparable接口，可使用罕铞泱殳compareTo方法来比较大小先来个遍历enum的代码Co颊俄岿髭de:package chapter4;/** * Created by MyWorld on 2016/3/21. */enum Season { Spring, Summer, Autumn, Winter}public class EnumCompare { public static void main(String[] args) { for (Season season : Season.values()) { System.out.println(season + " " + season.ordinal()); } }}

2、执行上面的代码看看结果：Spring 0Summer 1Autumn 2Winter 3

3、看到了没，每个枚举值都有一个ordinal()方法，这个方法的执行结果是返回一个数。这个墙绅褡孛数据是什么四歹吭毳意义呢？看看源码呢源码：/** * Returns the ordinal of this enumeration constant (its position * in its enum declaration, where the initial constant is assigned * an ordinal of zero). * * Most programmers will have no use for this method. It is * designed for use by sophisticated enum-based data structures, such * as {@link java.util.EnumSet} and {@link java.util.EnumMap}. * * @return the ordinal of this enumeration constant */ public final int ordinal() { return ordinal; }

4、直接使用枚举对象进行比较大小，就是使用这个值使用Compare比较大小Code:System.out.println("Compare to autumn:" + season.compareTo(Season.Autumn));

5、执行下，看看结果与预期的是否一致是一致的！！Output:Spring 0Compare to autumn:-2Summer 1Compare to autumn:-1Autumn 2Compare to autumn:0Winter 3Compare to autumn:1

6、既然有ordinal()方法，能不能使用==运算符呢改下代码Code:System.out.println("Compare to autumn:" + (season == Season.Autumn));

7、执行下，看看结果是否与预期一致一致的.枚举值之间是可以使用==来比较大小的Output:Spring 0Compare to autumn:-2Compare to autumn:falseSummer 1Compare to autumn:-1Compare to autumn:falseAutumn 2Compare to autumn:0Compare to autumn:trueWinter 3Compare to autumn:1Compare to autumn:false