如何在@RestController响应中打印List（）？

Question

I've a controller in a Spring App with this Code:

@RequestMapping("/")
@ResponseBody
public ResponseObject index(){
    System.out.println(this.sf);
    Session session = sf.openSession();
    List<Project> projects = session.createQuery("from Project").list();
    session.close();
    System.out.println(projects);
    return new ResponseObject(projects);
}

I've tried to return List<Project> and also my new created Object ResponseObject with this code:

public class ResponseObject {
    protected Object data;
    protected Object error;

    public ResponseObject(Object data) {
        this.data = data;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public Object getError() {
        return error;
    }

    public void setError(Object error) {
        this.error = error;
    }
}

But in all cases my JSON Reponse looks like: {"data":[{}],"error":null} .

Projects output is : [Project{id=1, name='Digital project'}]

Can anybody tell me why my List is not included in the JSON? Thanks!

Answer 1

protected Object data;

改成

protected List<Object> data;

Answer 2

You need to return a ResponseEntity like :

return new ResponseEntity<List<Project>>(projects, HttpStatus.OK);

see http://docs.spring.io/autorepo/docs/spring/4.0.2.RELEASE/javadoc-api/org/springframework/http/ResponseEntity.html

Provided you have Jackson in the classpath, which if you're using Spring boot you do everything will be de-serialized correctly. You do not need the ResponseObject class.