如何映射postgresql“时间戳与时区”在JPA 2实体中 [英] How to map postgresql "timestamp with time zone" in a JPA 2 entity
问题描述
我有一个JPA 2应用程序(使用Hibernate 3.6作为JPA实现),它使用Postgresql(使用9.0-801.jdbc3 JDBC驱动程序)。
我是在将时区与时区字段映射到我的JPA实体时遇到问题。
以下是一个例子:
CREATE TABLE主题
(
id序列NOT NULL,
#对该问题不重要的字段已被编辑出
run_from带时区的时间戳NOT NULL,
带时区的run_to时间戳NOT NULL,
CONSTRAINT theme_pkey PRIMARY KEY(id),
CONSTRAINT theme_name_key UNIQUE(name)
)
我试图映射如下:
@Entity
@Table(模式=content,name =theme)
public class Theme extends AbstractBaseEntity {
private static final long serialVersionUID = 1L;
@Column(name =run_from)
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private日期runFrom;
@Column(name =run_to)
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private日期runTo;
/ *实体的其余部分已被编辑* /
我一直以下面的根本原因得到一个异常:由以下原因引发:org.hibernate.HibernateException:创建的列的public.backend_themetopic中的列类型错误。发现:timestamptz,expected:date
我曾尝试过
- 用
java.util.Date替换
- 使用java.util.Calendar
java.sql.Timestamp
没有区别 - - 抱怨我无法应用
@Temporal
注释到时间戳
- 使用
org.joda.time.DateTime
code>自定义
@Type
注释( @Type(type =org.joda.time.contrib.hibernate.PersistentDateTimeTZ)
限制
- 此应用程序与遗留系统交互 - 因此,更改日期字段的类型不是一个好选择
我的问题是:我应该如何将这些时区感知时间戳映射到我的JPA实体中?
我最终做出了这个工作 - 以一种骇人的方式y - 通过关闭模式验证。
以前,我有< property name =hibernate.hbm2ddl.autovalue =validate在我的persistence.xml中/>\"hibernate.hbm2ddl.auto
>。当我注释掉这个属性时,我的应用服务器启动了,模型工作了。
我的实体的最终形式为:
@Entity
@Table(schema =content,name =theme)
public class Theme extends AbstractBaseEntity {
private static final long serialVersionUID = 1L;
@Column(name =run_from,columnDefinition =timestamp with time zone not null)
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private日期runFrom;
@Column(name =run_to,columnDefinition =timestampt with time zone not null)
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private日期runTo;
$ b $ * * Getters,setters,.hashCode(),.equals()等省略* /
在阅读了这篇文章后,我得到的印象是,没有简单的方法将Postgresql时间戳与时区列映射。
一些JPA实现+数据库组合本身支持这个(EclipseLink + Oracle就是一个例子)。对于使用jodatime扩展的休眠模式,可以使用时区的正常时间戳+ varchar字段来存储时区感知时间戳(由于受限于更改数据库模式,我无法这样做)。 Jadira用户类型或完全自定义的用户类型也可用于解决此问题。
我需要说明的是,这个实体的用例是只读,所以我可以用一个看似天真的解决方案逃脱。
I have a JPA 2 application ( with Hibernate 3.6 as the JPA implementation ) that uses Postgresql ( with the 9.0-801.jdbc3 JDBC driver ).
I am having trouble mapping "timestamp with time zone" fields into my JPA entities.
Here is an example:
CREATE TABLE theme
(
id serial NOT NULL,
# Fields that are not material to the question have been edited out
run_from timestamp with time zone NOT NULL,
run_to timestamp with time zone NOT NULL,
CONSTRAINT theme_pkey PRIMARY KEY (id ),
CONSTRAINT theme_name_key UNIQUE (name )
)
I have tried to map as follows:
@Entity
@Table(schema = "content", name = "theme")
public class Theme extends AbstractBaseEntity {
private static final long serialVersionUID = 1L;
@Column(name = "run_from")
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private Date runFrom;
@Column(name = "run_to")
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private Date runTo;
/* The rest of the entity has been edited out */
I keep on getting an exception with the following root cause: Caused by: org.hibernate.HibernateException: Wrong column type in public.backend_themetopic for column created. Found: timestamptz, expected: date
What I have tried
- replacing
java.util.Calendar
withjava.util.Date
- made no difference - using
java.sql.Timestamp
- complained that I cannot apply the@Temporal
annotation to aTimestamp
- using
org.joda.time.DateTime
with a custom@Type
annotation (@Type(type="org.joda.time.contrib.hibernate.PersistentDateTimeTZ")
) also did not work
Constraints
- This application interacts with a "legacy system" - so, changing the types of the date fields is not a good option
My question is: how should I map these timezone aware timestamps into my JPA entities?
I eventually made this "work" - in a hackish sort of way - by turning off schema validation.
Previously, I had <property name="hibernate.hbm2ddl.auto" value="validate"/>"hibernate.hbm2ddl.auto"
in my persistence.xml. When I commented out this property, my app server started and the model "worked".
The final form of my entity was:
@Entity
@Table(schema = "content", name = "theme")
public class Theme extends AbstractBaseEntity {
private static final long serialVersionUID = 1L;
@Column(name = "run_from", columnDefinition = "timestamp with time zone not null")
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private Date runFrom;
@Column(name = "run_to", columnDefinition = "timestampt with time zone not null")
@NotNull
@Temporal(TemporalType.TIMESTAMP)
private Date runTo;
/* Getters, setters, .hashCode(), .equals() etc omitted */
After reading quite a bit on this, I got the impression is that there is no easy way to map Postgresql timestamp with time zone columns.
Some JPA implementation + database combinations support this natively ( EclipseLink + Oracle is one example ). For hibernate, with jodatime extensions, it is possible to store timezone aware timestamps using a normal timestamp + a varchar field for the timezone( I could not do that since I was constrained from changing the database schema ). Jadira user types or completely custom user types can also be used to tackle this problem.
I need to note that my use-case for this entity is "read only", so I could get away with a seemingly naive "solution".
这篇关于如何映射postgresql“时间戳与时区”在JPA 2实体中的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!