如何将 ArrayList 发布到 Spring Boot H2 DB

Question

我收到以下错误：

{"timestamp":1535929757444,"status":500,"error":"Internal Server Error","exception":"org.springframework.dao.DataIntegrityViolationException","message":"could not execute statement; SQL [n/a]; constraint [\"PRIMARY KEY ON PUBLIC.WT_TASK(TASK_ID)\"; SQL statement:\ninsert into wt_task (exercise_id, task_id) values (?, ?) [23505-196]]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement","path":"/api/word-transformation/new"}

我能够创建一个服务来从数据库中获取 JSON，但我无法上传它们。

这是我的服务：

public WordTransformationExercise save(WordTransformationExerciseRequest wtRequest) {
    WordTransformationExercise wordTransformation = new WordTransformationExercise();
    wordTransformation.setAuthorId(wtRequest.getAuthor_id());

    List<WordTransformationTaskRequest> testP = wtRequest.getwt_task();

    List<WordTransformation> thisIsIt = new ArrayList<WordTransformation>();
    for(WordTransformationTaskRequest task : testP) {
          WordTransformation send = new WordTransformation();
          send.setBody(task.getBody());
          send.setResult(task.getResult());
          send.setWord(task.getWord());
          send.setWordAtIndex(task.getWord_at_index());
          thisIsIt.add(send);
    }
    wordTransformation.setwt_task(thisIsIt);

    this.wtRepository.save(wordTransformation);

    return wordTransformation;
  }

这是我的实体：

    @Entity
@Table(name = "wt_exercise")
public class WordTransformationExercise implements Serializable {
      @Id
      @Column(name = "id")
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      private Long id;

      @Column(name = "author_id")
      private Long authorId;

      @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
      @JoinTable(name = "wt_task",
              joinColumns = @JoinColumn(name = "exercise_id", referencedColumnName = "id"),
              inverseJoinColumns = @JoinColumn(name = "task_id", referencedColumnName = "task_id"))
      private List<WordTransformation> wt_task;

      public Long getId() {
            return id;
          }

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

      public Long getAuthorId() {
            return authorId;
          }

      public void setAuthorId(Long authorId) {
            this.authorId = authorId;
          }

      public void setwt_task(List<WordTransformation> list) {
          this.wt_task = list;
          }

          public Collection<?> getwt_task() {
            return this.wt_task;
          }
}

这是任务实体：

    @Entity
@Table(name = "wt_task")
public class WordTransformation implements Serializable {

    @Id
    @Column(name = "task_id")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long task_id;

    @Column(name = "body")
    private String body;

    @Column(name = "result")
    private String result;

    @Column(name = "word")
    private String word;

    @Column(name = "word_at_index")
    private Integer wordAtIndex;

    @Column(name = "exercise_id")
    private Long exercise_id;

    public void setExercise_id(Long exercise_id) {
        this.exercise_id = exercise_id;
    }

    public Long getExercise_id() {
        return exercise_id;
    }

    public void setId(Long task_id) {
        this.task_id = task_id;
    }

    public Long getId() {
        return task_id;
    }

    public void setBody(String body) {
        this.body = body;
    }

    public String getBody() {
        return body;
    }

    public void setResult(String result) {
        this.result = result;
    }

    public String getResult() {
        return result;
    }

    public void setWord(String word) {
        this.word = word;
    }

    public String getWord() {
        return word;
    }

    public void setWordAtIndex(Integer wordAtIndex) {
        this.wordAtIndex = wordAtIndex;
    }

    public Integer getWordAtIndex() {
        return wordAtIndex;
    }
}

当我将 wt_task 设置为 null 时，我的 API 可以正常返回“id”和“authorId”

这是我的 sql 示例：

INSERT INTO wt_exercise (id, author_id) VALUES (2, 2);

INSERT INTO wt_task(body, result, word, word_at_index, exercise_id, task_id) VALUES ('please start', 'running', 'run', 13, 2, 2);

Answer 1

这取决于你想做什么。

如果您尝试更新现有实体，则应从存储库中检索它并设置值，而不是创建新对象并尝试使用现有键保存它。

如果您尝试创建新事物，则根本不要设置密钥。