Java高质量代码之 — 枚举与注解_JAVA_编程开发_程序员俱乐部

class="java" name="code">
public interface Test {

	int SPRING = 0;
	int Summer = 1;
	int Autumn = 2;
	int Winter = 3;
}

public enum Test {
	SPRING, SUMMER, AUTUMN, WINTER
}

public static void main(String[] args) {
		int num = 1;
		switch (num) {
		case TestInterface.spring:
			System.out.println("Spring");
			break;
		case TestInterface.summer:
			System.out.println("Summer");
			break;
		case TestInterface.autumn:
			System.out.println("Autumn");
			break;
		case TestInterface.winter:
			System.out.println("Winter");
			break;
		default:
			System.out.println("error");
		}

		// Enum
		TestEnum enum1 = TestEnum.SUMMER;
		switch (enum1) {
		case SPRING:
			System.out.println(TestEnum.SPRING.name());
			break;
		case SUMMER:
			System.out.println(TestEnum.SUMMER.name());
			break;
		case AUTUMN:
			System.out.println(TestEnum.AUTUMN.name());
			break;
		case WINTER:
			System.out.println(TestEnum.WINTER.name());
			break;
		}
	}

public enum TestEnum {
	SPRING("春天"), SUMMER("夏天"), AUTUMN("秋天"), WINTER("冬天");

	private String name;

	TestEnum(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

}

public static void main(String[] args) {
		String str = "Spring";
		TestEnum enum1 = TestEnum.valueOf(str);
		if (enum1 == null)
			System.out.println("转换失败");
		else
			System.out.println("转换成功");

		// 很遗憾,程序运行结果抛出java.lang.IllegalArgumentException
	}

public static void main(String[] args) {
		String str = "Spring";
		TestEnum enum1 = null;
		for (TestEnum e : TestEnum.values()) {
			if (str.equals(e.getName())) {
				enum1 = TestEnum.valueOf(str);
			}
		}
		// 先进行判断即可解决异常参数问题
	}

interface Car {

}

class FordCar implements Car {

}

class BuickCar implements Car {

}

class CarFactory {
	public static Car createCar(Class<? extends Car> c) {
		try {
			return (Car) c.newInstance();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}
}

public enum CarFactory {

	FordCar {
		@Override
		public Car createCar() {
			return new FordCar();
		}
	},
	BuickCar {
		@Override
		public Car createCar() {
			return BuickCar();
		}
	};
	public abstract Car createCar();
}

public static void main(String[] args) {
		EnumSet<TestEnum> enumSet = EnumSet.allOf(TestEnum.class);

		// LargeTestEnum数量为>64
		EnumSet<LargeTestEnum> enumSet2 = EnumSet.allOf(LargeTestEnum.class);

		System.out.println(enumSet.getClass());
		// 输出为java.util.RegularEnumSet

		System.out.println(enumSet2.getClass());
		// 输出为java.util.JumboEnumSet

	}

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Inherited
public @interface TestAnnotation {
	String test() default "Hello World";
}