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本文介绍如何在 Java 中将 Enum 转换为 Int。

在 Java 中将 Enum 转换为 Int

Java 不提供将 enum 转换为 int 或反之亦然的内置功能，但我们可以创建方法来执行这些操作。 我们可以使用 value() 方法将具有 int 值的枚举转换为 int。

让我们看看分步过程：

首先，用 int 值生成 Enum。 在我们的例子中：

enum Cars {
    Toyota(10),
    Mercedes(20),
    Tesla(30),
    BMW(40),
    Audi(50);
}

创建一个方法来获取枚举 Cars 值。

public int getCarAsInt() {
        return cars;
}

创建一个方法将 Cars 枚举成员转换为 int。 该方法将包括一个 for 循环和一个 if 条件语句，该语句返回整数值。

public static int convertCarToInt(Cars inputCar) {
        for (Cars cars : Cars.values()) {
            if (cars.getCarAsInt() == inputCar.getCarAsInt()) {
                return cars.getCarAsInt();
            }
        }
        return -1;
}

我们还可以创建一个类似的方法将 int 转换为 enum Cars。

public static Cars convertIntToCar(int intCars) {
        for (Cars cars : Cars.values()) {
            if (cars.getCarAsInt() == intCars) {
                return cars;
            }
        }
        return null;
    }

最后，将上述方法应用于每个枚举成员。 让我们尝试一个示例，并将每个方法应用于枚举 Cars 的每个成员，这会将枚举成员转换为 int，然后将 int 转换回枚举成员：

package jiyik;
enum Cars {
    Toyota(10),
    Mercedes(20),
    Tesla(30),
    BMW(40),
    Audi(50);
    private final int cars;
    Cars(int cars) {
        this.cars = cars;
    }
    public int getCarAsInt() {
        return cars;
    }
    public static int convertCarToInt(Cars inputCar) {
        for (Cars cars : Cars.values()) {
            if (cars.getCarAsInt() == inputCar.getCarAsInt()) {
                return cars.getCarAsInt();
            }
        }
        return -1;
    }
    public static Cars convertIntToCar(int intCars) {
        for (Cars cars : Cars.values()) {
            if (cars.getCarAsInt() == intCars) {
                return cars;
            }
        }
        return null;
    }
}
public class Example {
    public static void main(String[] args) {
        // For enum member Toyota
        Cars Toyota_Car = Cars.Toyota;
        int intCars = Toyota_Car.getCarAsInt();
        // Get car as integer value
        System.out.println("Get Toyota car as int value :" + intCars);
        Toyota_Car = Cars.convertIntToCar(10);
        // Convert integer value to corresponding car value
        System.out.println("Convert integer 10 to car enum :" + Toyota_Car);
        intCars = Cars.convertCarToInt(Cars.Toyota);
        // Convert Cars value to corresponding integer value
        System.out.println("Convert Toyota car to integer :" + intCars + "\n");
        // For enum member Mercedes
        Cars Mercedes_Car = Cars.Mercedes;
        intCars = Mercedes_Car.getCarAsInt();
        // Get car as integer value
        System.out.println("Get Mercedes car as int value :" + intCars);
        Mercedes_Car = Cars.convertIntToCar(20);
        // Convert integer value to corresponding car value
        System.out.println("Convert integer 10 to car enum :" + Mercedes_Car);
        intCars = Cars.convertCarToInt(Cars.Mercedes);
        // Convert Cars value to corresponding integer value
        System.out.println("Convert Mercedes car to integer :" + intCars+ "\n");
        // For enum member Tesla
        Cars Tesla_Car = Cars.Tesla;
        intCars = Tesla_Car.getCarAsInt();
        // Get car as integer value
        System.out.println("Get Tesla car as int value :" + intCars);
        Tesla_Car = Cars.convertIntToCar(30);
        // Convert integer value to corresponding car value
        System.out.println("Convert integer 10 to car enum :" + Tesla_Car);
        intCars = Cars.convertCarToInt(Cars.Tesla);
        // Convert Cars value to corresponding integer value
        System.out.println("Convert Tesla car to integer :" + intCars+ "\n");
        // For enum member BMW
        Cars BMW_Car = Cars.BMW;
        intCars = BMW_Car.getCarAsInt();
        // Get car as integer value
        System.out.println("Get BMW car as int value :" + intCars);
        BMW_Car = Cars.convertIntToCar(40);
        // Convert integer value to corresponding car value
        System.out.println("Convert integer 10 to car enum :" + BMW_Car);
        intCars = Cars.convertCarToInt(Cars.BMW);
        // Convert Cars value to corresponding integer value
        System.out.println("Convert BMW car to integer :" + intCars+ "\n");
        // For enum member Audi
        Cars Audi_Car = Cars.Audi;
        intCars = Audi_Car.getCarAsInt();
        // Get car as integer value
        System.out.println("Get Audi car as int value :" + intCars);
        Audi_Car = Cars.convertIntToCar(50);
        // Convert integer value to corresponding car value
        System.out.println("Convert integer 10 to car enum :" + Audi_Car);
        intCars = Cars.convertCarToInt(Cars.Audi);
        // Convert Cars value to corresponding integer value
        System.out.println("Convert Audi car to integer :" + intCars+ "\n");
    }
}

上面的代码会将每个枚举 Cars 成员转换为 int，反之亦然。 查看输出：

Get Toyota car as int value :10
Convert integer 10 to car enum :Toyota
Convert Toyota car to integer :10

Get Mercedes car as int value :20
Convert integer 10 to car enum :Mercedes
Convert Mercedes car to integer :20

Get Tesla car as int value :30
Convert integer 10 to car enum :Tesla
Convert Tesla car to integer :30

Get BMW car as int value :40
Convert integer 10 to car enum :BMW
Convert BMW car to integer :40

Get Audi car as int value :50
Convert integer 10 to car enum :Audi
Convert Audi car to integer :50