switch (day) { case MONDAY: case FRIDAY: case SUNDAY: System.out.println(6); break; case TUESDAY: System.out.println(7); break; case THURSDAY: case SATURDAY: System.out.println(8); break; case WEDNESDAY: System.out.println(9); break;}
在Java 12中,Switch表达式可以改为如下写法:
switch (day) { case MONDAY, FRIDAY, SUNDAY -> System.out.println(6); case TUESDAY -> System.out.println(7); case THURSDAY, SATURDAY -> System.out.println(8); case WEDNESDAY -> System.out.println(9);}
还能支持在表达式中返回值:
int numLetters = switch (day) { case MONDAY, FRIDAY, SUNDAY -> 6; case TUESDAY -> 7; case THURSDAY, SATURDAY -> 8; case WEDNESDAY -> 9;};
在Java 13中,Switch表达式可以改为如下写法:
int date = switch (day) { case MONDAY, FRIDAY, SUNDAY : yield 6; case TUESDAY : yield 7; case THURSDAY, SATURDAY : yield 8; case WEDNESDAY : yield 9; default : yield 1; // default条件是必须的};System.out.println(date);
需要注意的是,在使用yield时,必须要有default条件。