使用JPA Query从数据库中检索UserRequest对象，如下所示。
@Query("SELECT req.supervisorEmail from User u, UserRequest as req WHERE u.username = req.userRequestName and req.userRequestRole= '4' and u.active=true")
public List<UserRequest> getSupervisorEmailIds();
正在具有
UserRequest POJO类，如下所示。public class UserRequest implements Identifiable<Long>, LazilyLoadable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@JsonIgnore
private Long id;
@Column(name = "supervisor_email")
private String supervisorEmail;
@Column(name="user_request_name")
private String userRequestName;
@Column(name="user_request_role")
private String userRequestRole;
}
当尝试遍历
UserRequest对象时，获取以下代码的ClassCastException。List<UserRequest> supervisorEmailIds = userService.getSupervisorEmailIds();
for(UserRequest s: supervisorEmailIds) { // throwing exception on this line.
if(s!=null) {
System.out.println("Printing -->"+s.getSupervisorEmail());
}
System.out.println("Null error");
}
以下是错误越来越严重。
2019-02-22 00:34:26,719 [http-9191-1] ERROR com.cat.pscs.api.controller.BaseController: 83 - Unhandled exception while processing request for URL : http://localhost:9191/security/users/get-supervisor-emailids with exception : java.lang.String cannot be cast to com.cat.pscs.security.model.UserRequest
java.lang.ClassCastException：无法将java.lang.String强制转换为com.cat.pscs.security.model.UserRequest
在com.cat.pscs.security.controller.UserController.getSupervisorEmailIds（UserController.java:320）
最佳答案
您确定下面的行返回UserRequestList吗？我认为它返回字符串列表
List<UserRequest> supervisorEmailIds = userService.getSupervisorEmailIds();
只需更改返回UserRequest对象列表的sql查询即可。