java - 如何以嵌套的json格式返回DB数据？

Question

我已经以 json 格式返回数据，但我想将其转换为嵌套的 json 格式数据。

我的代码是在 spring 中编写的，如下

@GET
@Path("/findall")
public List<UserRole> getAll() {

             return userroleservice.findAll();
}

该程序返回以下输出

[{"roleId":1,"roleName":"system Admin","createUser":"1","createActive":"N"},{"roleId":2,"roleName":"admin","createUser":"1","createActive":"Y"},{"roleId":3,"roleName":"system Admin","createUser":"1","createActive":"Y"}]

如何将其转换为嵌套的 json 格式

  [{ "id": 1, "data": "Category", "attr": { "id": "1", "selected": false }, "children":
                [
                    { "id": 2, "data": "SubCategory1", "attr": { "id": "2",      "selected": false }, "children":
                            [{ "id": 4, "data": "Item1", "attr": { "id": "4", "selected": false }, "children": [] },
                             { "id": 5, "data": "Item2", "attr": { "id": "5", "selected": false }, "children": [] },
                             { "id": 6, "data": "Item3", "attr": { "id": "6", "selected": false }, "children": [] }
                            ]
                    },

                    { "id": 3, "data": "SubCategory2", "attr": { "id": "3", "selected": false }, "children":
                             [{ "id": 7, "data": "Item4", "attr": { "id": "7", "selected": false }, "children": [] },
                              { "id": 8, "data": "Item5", "attr": { "id": "8", "selected": false }, "children": [] },
                              { "id": 9, "data": "Item6", "attr": { "id": "9", "selected": false }, "children": [] }
                             ]
                    }
                ]
}];

或者如何以嵌套的json格式返回DB数据??

请大家帮忙。

Answer 1

1. 创建一个与您想要的 JSON 格式相对应的新类。使用JSON TO POJO生成所需的java类链接
2. 完成 POJO 生成后，编写一个转换器，将 DB 对象转换为新的 POJO 对象。
3. 将相同的内容传递到下一层