Question

我有这段代码：

switch(month){
    case 1:
        System.out.print("January");
            break;
case 2:
    System.out.print("February");
        break;
case 3:
    System.out.print("March");
        break;
case 4:
    System.out.print("April");
        break;
case 5:
    System.out.print("May");
        break;
case 6:
    System.out.print("June");
        break;
case 7:
    System.out.print("July");
        break;
case 8:
    System.out.print("August");
        break;
case 9:
    System.out.print("September");
        break;
case 10:
    System.out.print("October");
        break;
case 11:
    System.out.print("November");
        break;
case 12:
    System.out.print("December");
        break;
}

好的，所以这段代码100％完美地工作...对于int月。我有另一个int（avgMonth）只能保持相同的值（1-12），我想只有相同的输出（月份）。如何在不必复制整个交换机和案例的情况下将avgMonth添加到此代码中？我尝试使用逗号（月，avgMonth）和＆amp;＆amp;'s（月和＆amp; avgMonth）以及+'s（月+ avgMonth），但无济于事。

Answer 1

将整个代码块封装在方法中，并将avgMonth和month作为参数传递。像这样：

public static void monthNumToName(int month) {
    // … same as before
}

或者，您可以使用Map：

简化代码

private static final Map<Integer, String> months;
static {
    months.put(1, "January");
    months.put(2, "February");
    months.put(3, "March");
    months.put(4, "April");
    months.put(5, "May");
    months.put(6, "June");
    months.put(7, "July");
    months.put(8, "August");
    months.put(9, "September");
    months.put(10, "October");
    months.put(11, "November");
    months.put(12, "December");
}

public static void monthNumToName(int month) {
    String name = months.get(month);
    if (name == null)
        throw new IllegalArgumentException("Invalid month number: " + month);
    System.out.print(name);
}

或更简单，只需使用数组，因为我们事先知道月份数量在1-12范围内受到限制：

private static final String[] months = {
    "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December"
};

public static void monthNumToName(int month) {
    if (month < 1 || month > 12)
        throw new IllegalArgumentException("Invalid month number: " + month);
    System.out.print(months[month-1]);
}

无论如何，当你需要打印月份名称时，请执行以下操作：

monthNumToName(month);
monthNumToName(avgMonth);

Answer 2

一个简单的数组可以完成这项工作，比如

String[] monthNames = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

那么你的月份就像

monthName = monthNames[month - 1];
avgMonthName = monthNames[avgmonth - 1];

Answer 3

您可以使用DateFormatSymbols方法{/ 3}}。

获取月份字符串。例如：“1月”，“2月”等

public static String getMonth(int month){
    return new DateFormatSymbols(Locale.UK).getMonths()[month-1];       
}

我做了month-1，因为你希望1用1月映射
您可以为getMonths()

Answer 4

怎么样

private static String[] MONTHS = "none,January,February,March,April,May,June,July,August,September,October,November,December".split(",");
public static void printMonth(int month) {
     System.out.print(MONTHS[month]);
}

Answer 5

首先，删除那个switch并假装你从来没有写过如此混乱的东西。

现在你有一个干净的平板，创建一个enum：

public enum Month {

    JANUARY(1),
    FEBRUARY(2),
    //other months
    ;

    private static final Map<Integer, Month> LOOKUP;

    static {
        final Map<Integer, Month> lookup = new HashMap<>();
        for (final Month month : values()) {
            lookup.put(month.number, month);
        }
        LOOKUP = Collections.unmodifiableMap(lookup);
    }

    public static Month fromNumber(final int num) {
        final Month month = LOOKUP.get(num);
        if(month == null)
            throw new IllegalArgumentException("No month for number " + num);
        return month;
    }

    private final int number;

    private Month(final int number) {
        this.number = number;
    }

    @Override
    public String toString() {
        final String name = name();
        return name.substring(0, 1) + name.substring(1).toLowerCase();
    }

}

并像这样使用

final Month month = Month.fromNumber(someInt);

为了打印月份，您可以：

System.out.println(month);

toString方法会将其转换为句子。

多个开关用于相同的情况

5 个答案: