小编典典
您可以使用具有以下两个CASE语句。
case text1:
case text4:{
//blah
break;
}
请参见此示例：该代码示例计算特定月份中的天数：
class SwitchDemo {
public static void main(String[] args) {
int month = 2;
int year = 2000;
int numDays = 0;
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
numDays = 31;
break;
case 4:
case 6:
case 9:
case 11:
numDays = 30;
break;
case 2:
if (((year % 4 == 0) &&
!(year % 100 == 0))
|| (year % 400 == 0))
numDays = 29;
else
numDays = 28;
break;
default:
System.out.println("Invalid month.");
break;
}
System.out.println("Number of Days = "
+ numDays);
}
}
这是代码的输出：
Number of Days = 29
贯穿：
另一个兴趣点是中断声明。每个break语句终止封闭的switch语句。控制流从切换块后的第一条语句继续。break语句是必需的，因为如果没有它们，则是switch块中的fall
through语句：匹配case标签之后的所有语句将按顺序执行，而不管后续case标签的表达式如何，直到遇到break语句为止。
示例代码：
public class SwitchFallThrough {
public static void main(String[] args) {
java.util.ArrayList futureMonths =
new java.util.ArrayList();
int month = 8;
switch (month) {
case 1: futureMonths.add("January");
case 2: futureMonths.add("February");
case 3: futureMonths.add("March");
case 4: futureMonths.add("April");
case 5: futureMonths.add("May");
case 6: futureMonths.add("June");
case 7: futureMonths.add("July");
case 8: futureMonths.add("August");
case 9: futureMonths.add("September");
case 10: futureMonths.add("October");
case 11: futureMonths.add("November");
case 12: futureMonths.add("December");
default: break;
}
if (futureMonths.isEmpty()) {
System.out.println("Invalid month number");
} else {
for (String monthName : futureMonths) {
System.out.println(monthName);
}
}
}
}
这是代码的输出：
August
September
October
November
December
在switch语句中使用字符串
在Java SE 7和更高版本中，可以在switch语句的表达式中使用String对象。以下代码示例，基于名为month的字符串的值显示月份数：
public class StringSwitchDemo {
public static int getMonthNumber(String month) {
int monthNumber = 0;
if (month == null) {
return monthNumber;
}
switch (month.toLowerCase()) {
case "january":
monthNumber = 1;
break;
case "february":
monthNumber = 2;
break;
case "march":
monthNumber = 3;
break;
case "april":
monthNumber = 4;
break;
case "may":
monthNumber = 5;
break;
case "june":
monthNumber = 6;
break;
case "july":
monthNumber = 7;
break;
case "august":
monthNumber = 8;
break;
case "september":
monthNumber = 9;
break;
case "october":
monthNumber = 10;
break;
case "november":
monthNumber = 11;
break;
case "december":
monthNumber = 12;
break;
default:
monthNumber = 0;
break;
}
return monthNumber;
}
public static void main(String[] args) {
String month = "August";
int returnedMonthNumber =
StringSwitchDemo.getMonthNumber(month);
if (returnedMonthNumber == 0) {
System.out.println("Invalid month");
} else {
System.out.println(returnedMonthNumber);
}
}
}
该代码的输出为8。
-09-11
