帶建構函式的枚舉

今天學習Java覺得帶建構函式的枚舉挺有意思的！代碼如下：

package com.jemsn.weekday;public class test {public static void main(String[] args) {weekday mon = weekday.mon;weekday tue = weekday.tue;weekday thus = weekday.thus;weekday fri = weekday.fri;}public enum weekday {mon(), tue(2), wes(3), thus(), fri;private weekday() {System.out.println("no args");}private weekday(int i) {System.out.println("have args " + i);};}}

輸出的結果如下：

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no args
have args 2
have args 3
no args
no args

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所以今天終於明白原來枚舉就像類一樣，可以有建構函式！並且上述枚舉裡的fri本身就是一個weekday對象！就像我們自己寫的fri=new weekday()一樣！

mon()就是執行不帶參數的建構函式！