How to use native query with spring repo mapped to custom object? - mysql

Question

I have table t1:
id | title
1 | title1
2 | title2
and I have the following spring repo method:
#Query(nativeQuery = true, value = "select id, title from t1")
public List<T1> getAll();
The custom class is:
public class T1 {
#JsonProperty("id")
private Integer id;
#JsonProperty("title")
private String title;
public T1(Integer id, String title) {
this.id = id;
this.title = title;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
}
I'm expecting to get the following json response:
{[{"id":1, "title":"titl1"}, {"id":2, "title":"titl2"}]}
However i'm getting this one:
[[1,"title1"],[2,"title2"]]
I'm using #RestController
#RequestMapping(method = RequestMethod.GET, value = "/test", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntityTestResponse> test() {
List<T1> list = testRepository.getAll();
TestResponse response = new TestResponse(list);
return new ResponseEntity<TestResponse>(response, HttpStatus.OK);
}
TestResponse class is:
public class TestResponse implements Serializable {
private TreeSet<T1> list = new TreeSet<>();
public TestResponse(TreeSet<T1> list) {
this.list = list;
}
....
Can you help with that?

Answer 1

This response is classic Java List, if you need it as JSON object, you have to use for example GSON and then you should write something like this:
sonBuilder builder = new GsonBuilder();
Gson gson = builder.create();
System.out.println(gson.toJson(YOUR_LIST_OF_T1));
Here are examples (included that was i wrote) and here is GitHub repo.

Answer 2

You can do it manually by overrite toString() method in T1 class if u need it in specific signature, and u didn't got any API doing what you want.
So if u try some thing like that
List<T1> list = testRepository.getAll();
StringBuilder strBuilder = new StringBuilder();
for(T1 t : list){
strBuilder.append(t.toString() + ", ");
}
String result = "";
if(strBuilder.length()!=0){
result = "{[" + strBuilder.substring(0, strBuilder.length()-2) + "]}";
}
System.out.println(result);
and class should overrite toString() method
class T1{
#JsonProperty("id")
private Integer id;
#JsonProperty("title")
private String title;
public T1(Integer id, String title) {
this.id = id;
this.title = title;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
#Override
public String toString() {
return "{\"id:\"" + id + ", \"title:\"" + title + "}";
}
}
Also if you want to use pure java standard library you can do it like next code but you will need to download javax.json-xxxx.jar(for example >> javax.json-1.0.4.jar) (that include providers or the implementation) to your library project path
But this next code will generate something like that
[{"id":1,"title":"Title1"},{"id":2,"title":"Title2"},{"id":3,"title":"Title3"}]
List<T1> list = testRepository.getAll();
JsonArrayBuilder jsonArray = Json.createArrayBuilder();
for(T1 t : list) {
jsonArray.add(Json.createObjectBuilder()
.add("id", t.getId())
.add("title", t.getTitle()));
}
System.out.println(jsonArray.build());