How do you receive a url parameter with a spring controller mapping

Question

This issue seems trivial  but I can t get it to work properly   I m calling my Spring controller mapping with jquery ajax   The value for someAttr is always empty string regardless of the value in the url   Please help me determine why   -URL called  http   localhost 8080 sitename controllerLevelMapping 1 someAttr 6   -Controller Mapping   RequestMapping value     someID     method RequestMethod GET  public  ResponseBody int getAttr  PathVariable value  someID   final String id            ModelAttribute value  someAttr   String someAttr          I hit some code here but the value for the ModelAttribute  someAttr  is empty string   The value for id is correctly set to  1

User · Answer

You have a lot of variants for using  RequestParam with additional optional elements  e g    RequestParam required   false  defaultValue    someValue   value  someAttr   String someAttr   If you don t put required   false - param will be required by default   defaultValue    someValue  - the default value to use as a fallback when the request parameter is not provided or has an empty value   If request and method param are the same - you don t need value    someAttr

User · Answer

You should be using  RequestParam instead of  ModelAttribute  e g    RequestMapping    someID    public  ResponseBody int getAttr  PathVariable value  someID   String id                                     RequestParam String someAttr        You can even omit  RequestParam altogether if you choose  and Spring will assume that s what it is    RequestMapping    someID    public  ResponseBody int getAttr  PathVariable value  someID   String id                                    String someAttr

[spring-mvc] How do you receive a url parameter with a spring controller mapping

Examples related to spring-mvc