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java枚举的原理是什么

发布时间:2022-06-01 15:16:17 来源:亿速云 阅读:203 作者:iii 栏目:大数据

这篇文章主要介绍“java枚举的原理是什么”,在日常操作中,相信很多人在java枚举的原理是什么问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”java枚举的原理是什么”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!

1、枚举是继承了抽象类Enum的类。

Season extends java.lang.Enum<Season>

2、通过一段静态代码块初始化枚举。

  static {};
    descriptor: ()V
    flags: ACC_STATIC
    Code:
      stack=4, locals=0, args_size=0
         0: new           #4                  // class io/github/yehongzhi/user/redisLock/Season
         3: dup
         4: ldc           #7                  // String SPRING
         6: iconst_0
         7: invokespecial #8                  // Method "<init>":(Ljava/lang/String;I)V
        10: putstatic     #9                  // Field SPRING:Lio/github/yehongzhi/user/redisLock/Season;
        13: new           #4                  // class io/github/yehongzhi/user/redisLock/Season
        16: dup
        17: ldc           #10                 // String SUMMER
        19: iconst_1
        20: invokespecial #8                  // Method "<init>":(Ljava/lang/String;I)V
        23: putstatic     #11                 // Field SUMMER:Lio/github/yehongzhi/user/redisLock/Season;
        26: new           #4                  // class io/github/yehongzhi/user/redisLock/Season
        29: dup
        30: ldc           #12                 // String AUTUMN
        32: iconst_2
        33: invokespecial #8                  // Method "<init>":(Ljava/lang/String;I)V
        36: putstatic     #13                 // Field AUTUMN:Lio/github/yehongzhi/user/redisLock/Season;
        39: new           #4                  // class io/github/yehongzhi/user/redisLock/Season
        42: dup
        43: ldc           #14                 // String WINTER
        45: iconst_3
        46: invokespecial #8                  // Method "<init>":(Ljava/lang/String;I)V
        49: putstatic     #15                 // Field WINTER:Lio/github/yehongzhi/user/redisLock/Season;
        52: iconst_4
        53: anewarray     #4                  // class io/github/yehongzhi/user/redisLock/Season
        56: dup
        57: iconst_0
        58: getstatic     #9                  // Field SPRING:Lio/github/yehongzhi/user/redisLock/Season;
        61: aastore
        62: dup
        63: iconst_1
        64: getstatic     #11                 // Field SUMMER:Lio/github/yehongzhi/user/redisLock/Season;
        67: aastore
        68: dup
        69: iconst_2
        70: getstatic     #13                 // Field AUTUMN:Lio/github/yehongzhi/user/redisLock/Season;
        73: aastore
        74: dup
        75: iconst_3
        76: getstatic     #15                 // Field WINTER:Lio/github/yehongzhi/user/redisLock/Season;
        79: aastore
        80: putstatic     #1                  // Field $VALUES:[Lio/github/yehongzhi/user/redisLock/Season;
        83: return

这段静态代码块的作用就是生成四个静态常量字段的值,还生成了$VALUES字段,用于保存枚举类定义的枚举常量。

3、关于values()方法,这是一个静态方法,作用是返回该枚举类的数组,底层实现原理,其实是这样的。

public static io.github.yehongzhi.user.redisLock.Season[] values();
    Code:
       0: getstatic     #1                  // Field $VALUES:[Lio/github/yehongzhi/user/redisLock/Season;
       3: invokevirtual #2                  // Method "[Lio/github/yehongzhi/user/redisLock/Season;".clone:()Ljava/lang/Object;
       6: checkcast     #3                  // class "[Lio/github/yehongzhi/user/redisLock/Season;"
       9: areturn

到此,关于“java枚举的原理是什么”的学习就结束了,希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习,快去试试吧!若想继续学习更多相关知识,请继续关注亿速云网站,小编会继续努力为大家带来更多实用的文章!

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