以下是直接来自baeldung参考页面的答案:- https://www.baeldung.com/spring-optional-path-variables

你不能有可选的路径变量，但你可以有两个控制器方法调用相同的服务代码:

@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();
}

Nicolai Ehmann的评论和wildloop的回答的简化示例(适用于Spring 4.3.3+)，基本上你现在可以使用required = false:

  @RequestMapping(value = {"/json/{type}", "/json" }, method = RequestMethod.GET)
  public @ResponseBody TestBean testAjax(@PathVariable(required = false) String type) {
    if (type != null) {
      // ...
    }
    return new TestBean();
  }

$.ajax({
            type : 'GET',
            url : '${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 ) {}

您还可以使用@PathVariable注释注入路径变量的Map，这一点并不广为人知。我不确定这个特性在Spring 3.0中是否可用，或者它是后来添加的，但这里有另一种解决示例的方法:

@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();
    }
}

如果你正在使用Spring 4.1和Java 8，你可以使用Java .util. optional，它在Spring MVC -中的@RequestParam， @PathVariable， @RequestHeader和@MatrixVariable中得到了支持

@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"
    }       
}