Spring 4.1与Java 8 java.util.Optional

[java]代码库

@RestController
@RequestMapping("o")
public class SampleController {
    @RequestMapping(value = "r", produces = "text/plain")
    public String requestParamAsOptional(
            @DateTimeFormat(iso = DateTimeFormat.ISO.DATE)
            @RequestParam(value = "ld") Optional<LocalDate> localDate) {
        StringBuilder result = new StringBuilder("ld: ");
        localDate.ifPresent(value -> result.append(value.toString()));
        return result.toString();
    }
}