如何在 Java 中将 ArrayList 转换为自定义 class？

Question

I have a small Spring Boot project containing model, repo, service, controller and a controller response model. 我正在使用 jdbc 来查询 H2 DB。

返回单个对象适用于 Controller 响应 model，但我无法通过响应 model 投射列表。 Causing class java.util.ArrayList cannot be cast to class com.leec.playground.model.Countries .

model 它本身包含一个在请求 controller 时不应公开的字段，因此响应为 model。 简单地对主 model 执行“findAll”查询会返回过多的数据。

代码如下：

国家（型号）：

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Countries {

    private Integer Id;
    private String Name;
    private String Time_zone;
    private String Currency;

}

国家回购：

@Repository
@AllArgsConstructor
public class CountriesRepo {

    private NamedParameterJdbcOperations jdbc;

    public List<Countries> findAll() {
        String sql = "select * from COUNTRIES";
        return jdbc.query(
                sql,
                new BeanPropertyRowMapper<>(Countries.class));
    }

    public Countries byId(Integer ID) {
        return jdbc.queryForObject("select * from COUNTRIES where ID = :ID", Map.of("ID", ID), (rs, rowNum) -> countries(rs));
    }

    @SneakyThrows
    private Countries countries(ResultSet rs) {
        return new Countries(
                rs.getInt("ID"),
                rs.getString("NAME"),
                rs.getString("TIME_ZONE"),
                rs.getString("CURRENCY")
        );
    }
}

国家ServiceImpl：

@Service
@AllArgsConstructor
public class CountriesServiceImpl {


    private final CountriesRepo repository;

    public List<Countries> findAll() {
        return repository.findAll();
    }

    public Countries byId(Integer id) {
        if (id != null) {
            return repository.byId(id);
        } else {
            return (Countries) findAll();
        }
    }
}

国家响应模型：

@AllArgsConstructor
@Value
public class CountriesResponseModel {
    Integer id;
    String name;
    String time_zone;

    public CountriesResponseModel(Countries countriesModel) {
        this.id = countriesModel.getId();
        this.name = countriesModel.getName();
        this.time_zone = countriesModel.getTime_zone();
    }
}

国家控制器：

@RestController
@RequestMapping("api")
@AllArgsConstructor
public class CountriesController {

    private CountriesServiceImpl service;

    @GetMapping()
    public ResponseEntity<List<CountriesResponseModel>> getAll() {
        return ResponseEntity.ok(new CountriesResponseModel(service.findAll()));
    }

    @GetMapping("filter")
    public ResponseEntity<CountriesResponseModel> getById(@RequestParam(value = "id", required = false) Integer id) {
        return ResponseEntity.ok(new CountriesResponseModel(service.byId(id)));
    }
}

在使用 findAll() 时如何使用定义的响应 model 的任何输入将不胜感激。