Question

我有一个映射到mysql数据库的注释对象。注释包含以下字段：（comment_id，commentText，commentdate）。 comment_id是一个自动生成的整数，而注释文本来自JSF页面的输入。当我调用addComment方法时，commentText按预期填充在数据库中，但是commentdate仍然为null，尽管在方法中设置了（通过创建calculateCurrentDateTime方法的返回值的字符串）。代码如下所示。如果有人能告诉我这是什么问题，我们非常感激。

@ManagedBean
@ViewScoped
public class CommentBean {

private Comment comment;
private static EntityManagerFactory factory;
private static final String PERSISTENCE_UNIT_NAME = "NeedABuilderUnit";
private List<BusinessAccount> businessAccount;
private List<Comment> listOfComments;

@PostConstruct
public void init() {
    comment = new Comment();
}

public String addComment(int contractorId) {
    factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
    EntityManager em = factory.createEntityManager();   
        em.getTransaction().begin();
        Query myQuery = em.createQuery("SELECT u FROM BusinessAccount u WHERE u.id=:id");
        myQuery.setParameter("id", contractorId);

        List<BusinessAccount> accounts=myQuery.getResultList();
        BusinessAccount account =accounts.get(0);

        String date=calculateCurrentDateTime();
        comment.setCommentdate(date);


        comment.setBusinessAccount(account); //managing both sides

        account.getComments().add(comment); //managing both sides
        em.persist(comment);

        em.getTransaction().commit();
        em.close();
        comment.setCommentText(null);

        return "success";
    }


public String calculateCurrentDateTime() {


       DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm");     
       //get current date time with Calendar()
       Calendar cal = Calendar.getInstance();
       String currentDate=dateFormat.format(cal.getTime());

return currentDate;

}


@Entity
@Table(name = "comments")
public class Comment {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int comment_id;

@Column(name = "comment_text")
private String commentText;

@Column(name = "date")
private String commentdate;



@ManyToOne(fetch = FetchType.LAZY)
@JoinColumns({ @JoinColumn(name = "contractor_id", referencedColumnName="id") })
private BusinessAccount businessAccount;

public BusinessAccount getBusinessAccount() {
    if (businessAccount == null) {
        businessAccount = new BusinessAccount();
    }
    return businessAccount;
}

public void setBusinessAccount(BusinessAccount businessAccount) {
    this.businessAccount = businessAccount;
}

public int getComment_id() {
    return comment_id;
}

public void setComment_id(int comment_id) {
    this.comment_id = comment_id;
}

public String getCommentText() {
    return commentText;
}

public void setCommentText(String commentText) {
    this.commentText = commentText;
}

public String getCommentdate() {
    return commentdate;
}

public void setCommentdate(String commentdate) {
    this.commentdate = commentdate;
}

}

Answer 1

将日期格式设为

Y-m-d H:i:s，这是mysql的格式

SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

Answer 2

为什么你不能改变它 @Column（name =“date”） private String commentdate;

到

@Type（类型= “org.jadira.usertype.dateandtime.joda.PersistentLocalDateTimeAsString”） @NotNull private LocalDateTime commentDate;

这样您就可以将currentDate设置为

commentDate = LocalDateTime.now（）;

这将解决问题，并且无需调用calculateCurrentDateTime（）方法，因为LocalDateTime.now（）将返回当前日期....

为什么日期没有保存到我的数据库？

2 个答案: