如何映射使用JPA持续时间类型 [英] How to map Duration type with JPA

问题描述

我有一个类，它是一个类型的属性字段 javax.xml.datatype.Duration中。它基本上重新presents的时间跨度（例如，4小时34分钟）。

JPA是告诉我这是一个无效的类型，它不激我。

请告诉我一个很好的解决方案呢？我可以实现我自己的时间类，但我不知道怎么去JPA接受它作为一种数据类型。

解决方案

  

请告诉我一个很好的解决方案呢？我可以实现我自己的时间类，但我不知道怎么去JPA接受它作为一种数据类型。

JPA不支持自定义类型，因此，如果你想要走这条路，你将不得不使用从您的提供商一个JPA扩展。例如，休眠允许定义<一href=\"http://docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html#mapping-types-custom\">custom值类型中，你与<声明一href=\"http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#d0e2794\"><$c$c>@Type.显然，这将损害供应商这可能是一个问题之间的可移植性。如果没有，那么你知道它是可行的。

使用标准JPA，传统的方法是添加另一个的getter / setter一对适应问题的性质和访问时进行转换。我会用一个龙来存储时间：

 公共myEntity所实现Serializable {
    私人长期身份证;
    私人javax.xml.datatype.Duration中的持续时间;    @ID
    @GeneratedValue
    众长的getId（）{
        返回this.id;
    }
    公共无效SETID（长ID）{
        this.id = ID;
    }    @短暂的
    公开时间getDuration（）{
        返回this.duration;
    }
    公共无效setDuration（持续时间）{
        this.duration =持续时间;
    }    众长getDurationAsJpaCompatibleType（）{
        返回MyXmlUtil.convertDurationToLong（this.duration）;
    }
    公共无效setDurationAsJpaCompatibleType（持续时间长）{
        setDuration（MyXmlUtil.convertLongToDuration（持续时间））;
    }
}
 

I have a property field in a class that is of type javax.xml.datatype.Duration. It basically represents a time span (e.g. 4 hours and 34 minutes).

JPA is telling me it is an invalid type, which doesn't shock me.

Whats a good solution this? I could implement my own Duration class, but I don't know how to get JPA to "accept" it as a datatype.

解决方案

Whats a good solution this? I could implement my own Duration class, but I don't know how to get JPA to "accept" it as a datatype.

JPA does not support custom types so if you want to go this way you'll have to use a JPA extension from your provider. For example, Hibernate allows to define custom value types that you declare with @Type. Obviously, this will harm portability between providers which might be a concern. If not, then you know it is doable.

With standard JPA, the traditional approach would be to add another getter/setter pair which adapt the problematic property and perform conversion when accessed. I would use a Long to store a duration:

public MyEntity implements Serializable {
    private Long id;
    private javax.xml.datatype.Duration duration;

    @Id
    @GeneratedValue
    public Long getId() {
        return this.id;
    }
    public void setId(Long id) {
        this.id = id;
    }

    @Transient
    public Duration getDuration() {
        return this.duration;
    }
    public void setDuration(Duration duration) {
        this.duration = duration;
    }

    public Long getDurationAsJpaCompatibleType() {
        return MyXmlUtil.convertDurationToLong(this.duration);
    }
    public void setDurationAsJpaCompatibleType(Long duration) {
        setDuration(MyXmlUtil.convertLongToDuration(duration));
    }
}

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