Introduction:
Welcome to a tutorial page on how to use a Switch statement within Java.
What is a Switch statement?
A Switch statement is used to check multiple cases or conditions for a particular instance. In Java 7, switch statements can be used for Strings and Integers whereas older versions of Java can only use Integers in a switch statement.
When is a Switch statement used?
A switch statement is very similar to a If and Else If statement except using a switch statement is much cleaner, less complex and you do not have to state the variable to check each time you want to check it - this does in-turn mean that you can only use one variable per switch statement.
Examples:
Setting up the methods to be created as examples:
System.
out.
println(getMonthNumber
("february")); System.
out.
println(getMonthString
(2));
Here is an integer example from the official Java Documents to convert the month integer to a string...
public static String getMonthString
(int month
) { switch (month) {
case 1: futureMonths = "January";
break;
case 2: futureMonths = "February";
break;
case 3: futureMonths = "March";
break;
case 4: futureMonths = "April";
break;
case 5: futureMonths = "May";
break;
case 6: futureMonths = "June";
break;
case 7: futureMonths = "July";
break;
case 8: futureMonths = "August";
break;
case 9: futureMonths = "September";
break;
case 10: futureMonths = "October";
break;
case 11: futureMonths = "November";
break;
case 12: futureMonths = "December";
break;
default: break;
}
return futureMonths;
}
and here is a Java 7 example of turning a string in to an integer...
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;
}
Which gives the combined output:
Finished!