尝试保存时发生Spring h2数据库错误

Question

守则

@Entity

public class TicketRequest {
    int id;
    Boolean checked;
    Map<Integer, int[]> num_lines;


    @Id  
    @GeneratedValue(strategy=GenerationType.AUTO) 
    @Column(name = "id")  
public int getId(){
    return id;
}

    @Column(name = "checked")  
public Boolean getChecked(){
    return checked;
}

    @ElementCollection
    @Column(name = "ticket_num")  
public Map<Integer, int[]> getTicketNum(){
    return num_lines;
}

public void setId(int id) {
    this.id = id;
}

public void setChecked(Boolean checked) {
    this.checked = checked;
}

public void setTicketNum(Map<Integer, int[]> num_lines){
    this.num_lines = num_lines;
}

@RestController的代码：

@RestController
public class LotteryController {

       private TicketRepository TicketRepository;

  @RequestMapping("/ticket")
  public TicketRequest CreateTicket(@RequestParam int line) {

      Map<Integer, int[]> lottery_lines = new HashMap<Integer,  int[]>();

      for(int i = 1; i<= line; i++) {
          int[] ints = new Random().ints(0, 3).distinct().limit(3).toArray();
          lottery_lines.put(i,  ints);

     // System.out.println("The Value are: " + Arrays.toString(lottery_lines.get(0)));
     } 

      TicketRequest response = new TicketRequest();
      response.setId(1);
      response.setChecked(false);
      response.setTicketNum(lottery_lines);


      TicketRepository.save(response);

    return response;

  }

}

public interface TicketRepository extends CrudRepository<TicketRequest, Integer>{

}

Answer 1

通过查看堆栈跟踪，错误与H2无关，您在控制器的第36行得到一个空指针。很遗憾，我从你的代码中分不出第36行。

仔细查看第36行，并尝试识别哪些内容可能为空。

我猜第36行是ticketRepository.save(response)；。TicketRepository从不在代码中初始化。您可能只是在该字段中缺少了@autowire。