Java 14 新特性:switch表达式增强

if (flag == 1) {
  log.info("didispace.com: 1");
} else if (flag == 2) {
  log.info("didispace.com: 2");
} else if (flag == 3) {
  log.info("didispace.com: 3");
} else if (flag == 4) {
  log.info("didispace.com: 4");
} else {
  log.info("didispace.com: x");
}

switch(flag) {
  case 1: 
    log.info("didispace.com: 1"); 
    break;
  case 2:
    log.info("didispace.com: 2");
    break;
  case 3:
    log.info("didispace.com: 3");
    break;
  case 4:
    log.info("didispace.com: 4");
    break;
  default:
    log.info("didispace.com: x");
}

switch(flag) {
  case 1  -> log.info("didispace.com: 1");
  case 2  -> log.info("didispace.com: 2");
  case 3  -> log.info("didispace.com: 3");
  case 4  -> log.info("didispace.com: 4");
  default -> log.info("didispace.com: x");
}