Convert Map to JSON using Jackson
gson, jackson, java, json, spring
Solution
You can convert `Map` to `JSON` using Jackson as follows:
Map<String,String> payload = new HashMap<>();
payload.put("key1","value1");
payload.put("key2","value2");
String json = new ObjectMapper().writeValueAsString(payload);
System.out.println(json);
Problem
How can I convert a Map to a valid JSON using Jackson? I am doing it using Google's GSON via a Spring Boot REST Post method... Here's the RESTful Web Service: ``` import java.util.Map; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonParser; import com.google.gson.Gson; @RestController @RequestMapping("/myservice") public class ValidationService { @RequestMapping(value="/validate", method = RequestMethod.POST) public void validate(@RequestBody Map<String, Object> payload) throws Exception { Gson gson = new Gson(); String json = gson.toJson(payload); System.out.println(json); } } ``` So, when I invoke it using this: ``` curl -H "Accept: application/json" -H "Content-type: application/json" \ -X POST -d '{"name":"value"}' http://localhost:8080/myservice/validate ``` Receive the following to stdout (this is exactly what I want): ``` {"name":"value"} ``` Is there a better way to do this using Jackson instead of Google's Gson and / or am I going about it the wrong way altogether?