With Spring can I make an optional path variable?
SpringRestSpring Problem Overview
With Spring 3.0, can I have an optional path variable?
For example
@RequestMapping(value = "/json/{type}", method = RequestMethod.GET)
public @ResponseBody TestBean testAjax(
HttpServletRequest req,
@PathVariable String type,
@RequestParam("track") String track) {
return new TestBean();
}
Here I would like /json/abc
or /json
to call the same method.
One obvious workaround declare type
as a request parameter:
@RequestMapping(value = "/json", method = RequestMethod.GET)
public @ResponseBody TestBean testAjax(
HttpServletRequest req,
@RequestParam(value = "type", required = false) String type,
@RequestParam("track") String track) {
return new TestBean();
}
and then /json?type=abc&track=aa
or /json?track=rr
will work
Spring Solutions
Solution 1 - Spring
You can't have optional path variables, but you can have two controller methods which call the same service code:
@RequestMapping(value = "/json/{type}", method = RequestMethod.GET)
public @ResponseBody TestBean typedTestBean(
HttpServletRequest req,
@PathVariable String type,
@RequestParam("track") String track) {
return getTestBean(type);
}
@RequestMapping(value = "/json", method = RequestMethod.GET)
public @ResponseBody TestBean testBean(
HttpServletRequest req,
@RequestParam("track") String track) {
return getTestBean();
}
Solution 2 - Spring
If you are using Spring 4.1 and Java 8 you can use java.util.Optional
which is supported in @RequestParam
, @PathVariable
, @RequestHeader
and @MatrixVariable
in Spring MVC -
@RequestMapping(value = {"/json/{type}", "/json" }, method = RequestMethod.GET)
public @ResponseBody TestBean typedTestBean(
@PathVariable Optional<String> type,
@RequestParam("track") String track) {
if (type.isPresent()) {
//type.get() will return type value
//corresponds to path "/json/{type}"
} else {
//corresponds to path "/json"
}
}
Solution 3 - Spring
It's not well known that you can also inject a Map of the path variables using the @PathVariable annotation. I'm not sure if this feature is available in Spring 3.0 or if it was added later, but here is another way to solve the example:
@RequestMapping(value={ "/json/{type}", "/json" }, method=RequestMethod.GET)
public @ResponseBody TestBean typedTestBean(
@PathVariable Map<String, String> pathVariables,
@RequestParam("track") String track) {
if (pathVariables.containsKey("type")) {
return new TestBean(pathVariables.get("type"));
} else {
return new TestBean();
}
}
Solution 4 - Spring
You could use a :
@RequestParam(value="somvalue",required=false)
for optional params rather than a pathVariable
Solution 5 - Spring
Spring 5 / Spring Boot 2 examples:
blocking
@GetMapping({"/dto-blocking/{type}", "/dto-blocking"})
public ResponseEntity<Dto> getDtoBlocking(
@PathVariable(name = "type", required = false) String type) {
if (StringUtils.isEmpty(type)) {
type = "default";
}
return ResponseEntity.ok().body(dtoBlockingRepo.findByType(type));
}
reactive
@GetMapping({"/dto-reactive/{type}", "/dto-reactive"})
public Mono<ResponseEntity<Dto>> getDtoReactive(
@PathVariable(name = "type", required = false) String type) {
if (StringUtils.isEmpty(type)) {
type = "default";
}
return dtoReactiveRepo.findByType(type).map(dto -> ResponseEntity.ok().body(dto));
}
Solution 6 - Spring
Simplified example of Nicolai Ehmann's comment and wildloop's answer (works with Spring 4.3.3+), basically you can use required = false
now:
@RequestMapping(value = {"/json/{type}", "/json" }, method = RequestMethod.GET)
public @ResponseBody TestBean testAjax(@PathVariable(required = false) String type) {
if (type != null) {
// ...
}
return new TestBean();
}
Solution 7 - Spring
Check this Spring 3 WebMVC - Optional Path Variables. It shows an article of making an extension to AntPathMatcher to enable optional path variables and might be of help. All credits to Sebastian Herold for posting the article.
Solution 8 - Spring
Here is the answer straight from baeldung's reference page :- https://www.baeldung.com/spring-optional-path-variables
Solution 9 - Spring
thanks Paul Wardrip in my case I use required.
@RequestMapping(value={ "/calificacion-usuario/{idUsuario}/{annio}/{mes}", "/calificacion-usuario/{idUsuario}" }, method=RequestMethod.GET)
public List<Calificacion> getCalificacionByUsuario(@PathVariable String idUsuario
, @PathVariable(required = false) Integer annio
, @PathVariable(required = false) Integer mes) throws Exception {
return repositoryCalificacion.findCalificacionByName(idUsuario, annio, mes);
}
Solution 10 - Spring
$.ajax({
type : 'GET',
url : '${pageContext.request.contextPath}/order/lastOrder',
data : {partyId : partyId, orderId :orderId},
success : function(data, textStatus, jqXHR) });
@RequestMapping(value = "/lastOrder", method=RequestMethod.GET)
public @ResponseBody OrderBean lastOrderDetail(@RequestParam(value="partyId") Long partyId,@RequestParam(value="orderId",required=false) Long orderId,Model m ) {}