如何从Spring MVC 3 Controller返回json形式的字符串？

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class MyController {

    @RequestMapping("/json")
    @ResponseBody
    public ResponseEntity<String> getJsonString() {
        // 创建一个Java对象
        MyObject myObject = new MyObject();
        myObject.setName("John");
        myObject.setAge(25);

        // 使用Jackson库将Java对象转换为JSON字符串
        ObjectMapper objectMapper = new ObjectMapper();
        String jsonString;
        try {
            jsonString = objectMapper.writeValueAsString(myObject);
        } catch (JsonProcessingException e) {
            // 处理异常情况
            return new ResponseEntity<>("Error occurred while converting to JSON", HttpStatus.INTERNAL_SERVER_ERROR);
        }

        // 返回JSON字符串
        return new ResponseEntity<>(jsonString, HttpStatus.OK);
    }
}