Java Enum equals()用法及代碼示例

Enum類equals()方法

• equals() 方法可在java.lang包。
• equals() 方法用於檢查此對象與給定對象的相等或不相等，或者換句話說，我們可以說此方法用於比較兩個對象。
• equals() 方法是一個非靜態方法，它隻能通過類對象訪問，如果我們嘗試使用類名訪問方法，那麽我們將得到一個錯誤。
• equals() 方法在比較兩個對象時不會拋出異常。

用法:

    public final boolean equals(Object obj2);

參數：

• Object ob2– 代表要比較的對象。

返回值：

這個方法的返回類型是boolean，它根據給定的情況返回以下值，

• 它返回true如果 Object1 等於 Object2。
• 它返回false如果 Object1 不等於 Object2。

例：

// Java program to demonstrate the example 
// of boolean equals(Object obj2) method of 
// Enum class

enum Weeks {
    SUN,
    MON,
    TUE,
    WED,
    THU,
    FRI,
    SAT;
}
public class Equals {
    public static void main(String args[]) {

        Weeks w1 = Weeks.SUN;
        Weeks w2 = Weeks.MON;
        Weeks w3 = Weeks.TUE;
        Weeks w4 = Weeks.WED;
        Weeks w5 = Weeks.THU;
        Weeks w6 = Weeks.FRI;
        Weeks w7 = Weeks.SAT;

        boolean res1 = w1.equals(w2);
        boolean res2 = w2.equals(w3);
        boolean res3 = w3.equals(w4);
        boolean res4 = w4.equals(w2);
        boolean res5 = w5.equals(w6);

        System.out.println("Is" + " " + w1.name() + " " + "same as" + " " + w2.name() + " " + res1);
        System.out.println("Is" + " " + w2.name() + " " + "same as" + " " + w3.name() + " " + res2);
        System.out.println("Is" + " " + w3.name() + " " + "same as" + " " + w4.name() + " " + res3);
        System.out.println("Is" + " " + w4.name() + " " + "same as" + " " + w2.name() + " " + res4);
        System.out.println("Is" + " " + w5.name() + " " + "same as" + " " + w6.name() + " " + res5);
    }
}

輸出

Is SUN same as MON false
Is MON same as TUE false
Is TUE same as WED false
Is WED same as MON false
Is THU same as FRI false