restful接口返回数据为空！

Question

写了一个接口，我用浏览器、postman、idea的restclient调用这个接口返回的都是

这是我的controller

@RestController
//@Controller
public class CarInfoController {

    @Autowired
    private CarInfoService carInfoService;

//    static Log log = LogFactory.getLog(CarInfoController.class.getName());

    @GetMapping("/select")
    public ResponseEntity<Carinfo> selectById(@RequestParam("id")String carNum){
//        log.debug("log4j日志开启");
        Carinfo c = new Carinfo();
        c.setCarnum(carNum);
        c.setMileageday(233.0);
        Carinfo carinfo = this.carInfoService.queryListById(c);
        System.out.println("-----------------------"+carinfo);
        System.out.println("ResponseEntity.ok(carinfo)==============="+ResponseEntity.ok(carinfo));
        return ResponseEntity.ok(carinfo);
    }
}

这是我的测试结果

```java
http://localhost:8080/select?id=1

HTTP/1.1 200 
Content-Length: 0
Date: Wed, 05 Oct 2022 08:19:07 GMT
Keep-Alive: timeout=60
Connection: keep-alive

<Response body is empty>



Response code: 200; Time: 461ms; Content length: 0 bytes

自己写的项目，没有使用方向，只是我自己配置了aop、拦截器等等

找不到原因

Answer 1

你carinfo结果是啥？