将Map键、值对转换为@responseBody对象的JSON属性

import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

@RestController
public class MyController {

    @RequestMapping(value = "/mapToJson", method = RequestMethod.GET)
    @ResponseBody
    public String mapToJson() {
        Map<String, Object> map = new HashMap<>();
        map.put("key1", "value1");
        map.put("key2", 123);
        map.put("key3", true);

        try {
            ObjectMapper objectMapper = new ObjectMapper();
            String json = objectMapper.writeValueAsString(map);
            return json;
        } catch (Exception e) {
            e.printStackTrace();
            return "Error occurred while converting map to JSON.";
        }
    }
}