Consuming incoming data with a reactive POST method

Any website that will serve up employee records must surely have a way to enter new ones, right? So, let’s create a web method that does just that by adding to the ApiController class we started in the previous section:

@PostMapping("/api/employees")
Mono<Employee> add(@RequestBody Mono<Employee> newEmployee) 
  {
    return newEmployee //
      .map(employee -> {
        DATABASE.put(employee.name(), employee);
        return employee;
      });
}

This Spring WebFlux controller has the following details:

• @PostMapping: Spring Web’s annotation to map HTTP POST /api/employees web calls to this method
• @RequestBody: This annotation tells Spring Web to deserialize the incoming HTTP request body into an Employee data...