在不同情况下使用不同的休眠用户类型

本文介绍了在不同情况下使用不同的休眠用户类型的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我使用Hibernate + JPA作为我的ORM解决方案。

I am using Hibernate + JPA as my ORM solution.

我使用HSQL的单元测试和PostgreSQL作为真正的数据库。

I am using HSQL for unit testing and PostgreSQL as the real database.

我希望能够使用的Postgres的原生 UUID 与Hibernate类型，并使用UUID在其字符串重新presentation与HSQL的单元测试（因为HSQL没有一个UUID类型）。

I want to be able to use Postgres's native UUID type with Hibernate, and use the UUID in its String representation with HSQL for unit testing (since HSQL does not have a UUID type).

我使用的是XML持久性与Postgres的和HSQL的单元测试不同的配置。

I am using a persistence XML with different configurations for Postgres and HSQL Unit Testing.

下面是我已经休眠看到我的自定义用户类型：

Here is how I have Hibernate "see" my custom UserType:

@Id @Column(name="UUID", length=36) @org.hibernate.annotations.Type(type="com.xxx.UUIDStringType") public UUID getUUID() { return uuid; } public void setUUID(UUID uuid) { this.uuid = uuid; }

和伟大工程。但是，我需要的是换出注解的com.xxx.UUIDStringType的一部分在XML或从无需重新编译更改的属性文件的能力。

and that works great. But what I need is the ability to swap out the "com.xxx.UUIDStringType" part of the annotation in XML or from a properties file that can be changed without re-compiling.

任何想法？

推荐答案

这问题真的老了，并已回答了很长一段时间，但最近我发现自己在这个相同的情况下，发现了一个很好的解决方案。对于初学者来说，我发现Hibernate有三种不同的内置UUID类型实现：

This question is really old and has been answered for a long time, but I recently found myself in this same situation and found a good solution. For starters, I discovered that Hibernate has three different built-in UUID type implementations:

二进制UUID ：存储UUID为二进制

UUID-CHAR ：存储UUID作为一个字符序列

PG-UUID ：使用本地Postgres的UUID类型

binary-uuid : stores the UUID as binary

uuid-char : stores the UUID as a character sequence

pg-uuid : uses the native Postgres UUID type

这些类型在默认情况下注册，并可以使用 @Type 标注某一领域，例如指定。

These types are registered by default and can be specified for a given field with a @Type annotation, e.g.

@Column @Type(type = "pg-uuid") private UUID myUuidField;

还有也的在方言覆盖默认类型的机制。因此，如果最终部署是跟一个Postgres数据库，但我们的单元测试使用HSQL，可以覆盖 PG-UUID 键入阅读写作/写入字符数据一个自定义的话，像这样：

There's also a mechanism for overriding default types in the Dialect. So if the final deployment is to talk to a Postgres database, but we the unit tests use HSQL, you can override the pg-uuid type to read/write character data by writing a custom dialect like so:

public class CustomHSQLDialect extends HSQLDialect { public CustomHSQLDialect() { super(); // overrides the default implementation of "pg-uuid" to replace it // with varchar-based storage. addTypeOverride(new UUIDCharType() { @Override public String getName() { return "pg-uuid"; } }); } }

现在只需插入自定义的方言，而在 PG-UUID 类型是在两个环境中使用。

Now just plug in the custom dialect, and the the pg-uuid type is available in both environments.