Map parameter as GET param in Spring REST controller

Question

How I can pass a Map parameter as a GET param in url to Spring REST controller ?

Solution 1

There are different ways (but a simple @RequestParam('myMap')Map<String,String> does not work - maybe not true anymore!)

The (IMHO) easiest solution is to use a command object then you could use [key] in the url to specifiy the map key:

@Controller

@RequestMapping("/demo")
public class DemoController {

    public static class Command{
        private Map<String, String> myMap;

        public Map<String, String> getMyMap() {return myMap;}
        public void setMyMap(Map<String, String> myMap) {this.myMap = myMap;}

        @Override
        public String toString() {
            return "Command [myMap=" + myMap + "]";
        }
    }
    
    @RequestMapping(method=RequestMethod.GET)
    public ModelAndView helloWorld(Command command) {
        System.out.println(command);
        return null;
    }
}

• Request: http://localhost:8080/demo?myMap[line1]=hello&myMap[line2]=world
• Output: Command [myMap={line1=hello, line2=world}]

Tested with Spring Boot 1.2.7

Solution 2

It’s possible to bind all request parameters in a Map just by adding a Map object after the annotation:

@RequestMapping("/demo")
public String example(@RequestParam Map<String, String> map){
    String apple = map.get("APPLE");//apple
    String banana = map.get("BANANA");//banana

    return apple + banana;
}

Request

/demo?APPLE=apple&BANANA=banana

Source -- https://reversecoding.net/spring-mvc-requestparam-binding-request-parameters/

Comments

[alexanoid]

Thanks Ralph! What do you think about an approach where we will pass @PathVariable List<String> map and map will contain something like this: 12:34,833:73,90:25 In the controller logic we can split list elements by ":" and get key/value pairs..

[Ralph]

Why do you want to do this, when the "save" solution is so easy? I you want to map it by your own, then you should have a look at matix variables: docs.spring.io/spring/docs/current/spring-framework-referenc‌​e/… and captaindebug.com/2013/04/…

[alexanoid]

because currently I have a following mapping @RequestMapping(value = "/criteria/{criteriaIds} where criteriaIds is a @PathVariable List<Long> criteriaIds. Right now I need to add double weight to some of criteriaId in criteriaIds list.