blocks|key|2958680|text|应该是uuid2|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2958681|...
@GenericGenerator(name+=+"uuid",+strategy+=+"uuid2")
...|code-block|syntax|javascript|2958682|参见5.1.2.2.1.+Various+additional+generators。|2958683|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.jboss.org/hibernate/core/3.6/reference/en-US/html/mapping.html#d0e5294^0|3|5|0|0|2|14|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

It should be <code>uuid2</code>:

<pre><code>...
@GenericGenerator(name = "uuid", strategy = "uuid2")
...
</code></pre>

See <a href="http://docs.jboss.org/hibernate/core/3.6/reference/en-US/html/mapping.html#d0e5294" rel="noreferrer">5.1.2.2.1. Various additional generators</a>.

blocks|key|262609|text|HibernateDoc说你可以使用下面的代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|262610|@Id
@GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid",+strategy+=+"uuid")
@Column(name+=+"uuid",+unique+=+true)
private+String+uuid;|code-block|syntax|javascript|262611|我希望你使用的是Hibernate+3.5。|262612|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#entity-hibspec-identifier^0|0|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

<a href="http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html_single/#entity-hibspec-identifier" rel="noreferrer">HibernateDoc</a> says you can use following:

<pre><code>@Id
@GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid", strategy = "uuid")
@Column(name = "uuid", unique = true)
private String uuid;
</code></pre>

I hope you are using Hibernate 3.5.

blocks|key|3172644|text|正如@natan在评论中指出的那样，如果你正在使用Hibernate+5，下面的代码就足够了：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3172645|@Id+
@GeneratedValue
private+java.util.UUID+id;|code-block|syntax|javascript|3172646|在MySQL中定义类型为BINARY(16)的id列，或者在其他SQL实现中定义它的等价物。|offset|length|style|CODE|3172647|entityMap^0|0|0|C|A|N|2|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

As @natan pointed out in a comment, if you are using Hibernate 5 the below code is sufficient:

<pre><code>@Id 
@GeneratedValue
private java.util.UUID id;
</code></pre>

Define the <code>id</code> column with the type of <code>BINARY(16)</code> in MySQL or it's equivalent in other SQL implementations.

blocks|key|262614|text|试试..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|262615|@Id
@GeneratedValue(generator+=+"uuid2")
@GenericGenerator(name+=+"uuid2",+strategy+=+"uuid2")
@Column(name+=+"uuid",+columnDefinition+=+"BINARY(16)")
public+UUID+getId()
{
++++return+id;
}

public+void+setId(UUID+i)
{
++++id+=+i;
}|code-block|syntax|javascript|262616|注意"uuid2“，而不是"uuid”。|262617|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try...

<pre><code>@Id
@GeneratedValue(generator = "uuid2")
@GenericGenerator(name = "uuid2", strategy = "uuid2")
@Column(name = "uuid", columnDefinition = "BINARY(16)")
public UUID getId()
{
 return id;
}

public void setId(UUID i)
{
 id = i;
}
</code></pre>

Note the "uuid2" as opposed to "uuid".

blocks|key|264786|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|264787|未知Id.generator:+hibernate-uuid|blockquote|264788|264789|264790|@Id
@GeneratedValue(generator+=+"uuid")
@GenericGenerator(name+=+"uuid",+strategy+=+"org.hibernate.id.UUIDGenerator")
@Column(name+=+"id",+unique+=+true)
public+String+getId()+{
++++return+id;
}

public+void+setId(String+id)+{
++++this.id+=+id;
}|code-block|syntax|javascript|264791|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|M|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|N|7|@]|8|@]|9|$]]|$1|D|3|-4|4|5|6|O|7|@]|8|@]|9|$]]|$1|E|3|-4|4|5|6|P|7|@]|8|@]|9|$]]|$1|F|3|G|4|H|6|Q|7|@]|8|@]|9|$I|J]]|$1|K|3|-4|4|5|6|R|7|@]|8|@]|9|$]]]|L|$]]

<blockquote>
 Unknown Id.generator: hibernate-uuid
</blockquote>

<pre><code>@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "org.hibernate.id.UUIDGenerator")
@Column(name = "id", unique = true)
public String getId() {
 return id;
}

public void setId(String id) {
 this.id = id;
}
</code></pre>

blocks|key|2958770|text|这将使用UUID+v4，自动生成的uuid将像通常的varchar(36)一样存储在列中|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2958771|@Id
@GeneratedValue(generator+=+"uuid2")
@GenericGenerator(name+=+"uuid2",+strategy+=+"uuid2")
@Column(length+=+36)
private+String+uuid;|code-block|syntax|javascript|2958772|这应该会对性能产生一些影响：|2958773|BINARY(16)|2958774|after+|unordered-list-item|2958775|
|2958776|消耗的大小大于|2958777|的消耗大小java.lang.String实例比java.util.UUID消耗更多的内存:+UUID字符串为112字节，UUID.|2958778|为32字节(即两个长整型%2B+obj标头|2958779|2958780|但是使用string‘’ed要容易得多--更容易编写查询，并且您可以看到表的内容。|2958781|在Hibernate+5.3上测试|2958782|entityMap^0|Q|B|0|0|0|0|A|0|0|0|0|5|G|O|E|1P|4|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|O|3|P|5|Q|7|1E|8|@]|D|@]|E|$]]|$1|R|3|S|5|6|7|1F|8|@]|D|@]|E|$]]|$1|T|3|U|5|Q|7|1G|8|@]|D|@]|E|$]]|$1|V|3|W|5|Q|7|1H|8|@$9|1I|A|1J|B|C]|$9|1K|A|1L|B|C]|$9|1M|A|1N|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|6|7|1O|8|@]|D|@]|E|$]]|$1|Z|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]|$1|10|3|11|5|6|7|1Q|8|@]|D|@]|E|$]]|$1|12|3|13|5|6|7|1R|8|@]|D|@]|E|$]]|$1|14|3|-4|5|6|7|1S|8|@]|D|@]|E|$]]]|15|$]]

This will use UUID v4 and the auto generated uuid will be stored in the column as usual <code>varchar(36)</code>:

<pre><code>@Id
@GeneratedValue(generator = "uuid2")
@GenericGenerator(name = "uuid2", strategy = "uuid2")
@Column(length = 36)
private String uuid;
</code></pre>

This should have some performance impact:

<ul>
<li>consumed size is more than <code>BINARY(16)</code></li>
<li>after hydration the <code>java.lang.String</code> instance consumes more memory than <code>java.util.UUID</code>: 112 bytes for UUID as string versus 32 bytes (i.e. two longs + obj header) for <code>UUID</code>.</li>
</ul>

But it's much more easier to work with string'ed UUID - easier to write queries and you can see the contents of the table.

Tested on Hibernate 5.3

blocks|key|266378|text|使用当前的5.4.2+Hibernate版本，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|266379|如果您希望数据库表中有一个人类可读的varchar(36)字段，|offset|length|style|BOLD|266380|而且在你的类中也是一个可序列化的Java+数据类型，|266381|您可以在声明字段成员的同时使用@Type(type+=+"uuid-char")++java.util.UUID类型。|CODE|266382|请注意，将MySQL中的字段长度从255减少到36，@Column(length+=+36)非常重要。|266383|请注意，对于PostgreSQL，您应该改用@Type(type+=+"pg-uuid")。|266384|import+org.hibernate.annotations.Type
import+java.util.UUID
import+javax.persistence.Column
import+javax.persistence.GeneratedValue
import+javax.persistence.Id

@Id+@GeneratedValue
@Type(type+=+"uuid-char")+@Column(length+=+36)
private+UUID+id;|code-block|syntax|javascript|266385|entityMap^0|0|I|B|0|5|G|0|F|P|16|E|0|Q|K|0|M|N|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Y|8|@$D|Z|E|10|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|11|8|@$D|12|E|13|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|14|8|@$D|15|E|16|F|L]|$D|17|E|18|F|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|19|8|@$D|1A|E|1B|F|L]]|9|@]|A|$]]|$1|O|3|P|5|6|7|1C|8|@$D|1D|E|1E|F|L]]|9|@]|A|$]]|$1|Q|3|R|5|S|7|1F|8|@]|9|@]|A|$T|U]]|$1|V|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|W|$]]

With current 5.4.2 Hibernate version, 

if you want a Human-Readable varchar(36) field in the database table, 
but also a Serializable UUID data type in your Java Class, 
you can use <code>@Type(type = "uuid-char")</code> at the same time you declare your field member with <code>java.util.UUID</code> type.

Note that <code>@Column(length = 36)</code> is important to reduce from 255 to 36 the field length in MySQL.

Note that with PostgreSQL you should use <code>@Type(type = "pg-uuid")</code> instead.

<pre class="lang-java prettyprint-override"><code>import org.hibernate.annotations.Type
import java.util.UUID
import javax.persistence.Column
import javax.persistence.GeneratedValue
import javax.persistence.Id

@Id @GeneratedValue
@Type(type = "uuid-char") @Column(length = 36)
private UUID id;
</code></pre>

blocks|key|264793|text|@Id
@GeneratedValue(generator+=+"uuid")
@GenericGenerator(name+=+"uuid",+strategy+=+"uuid")
@Column(name+=+"UUID_ID")
public+String+getId(){
return+id;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|264794|这是在Hibernate+5.0.11.FINAL中为uuid生成器使用注释的正确方法。|unstyled|264795|注意:它已被弃用。|264796|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid")
@Column(name = "UUID_ID")
public String getId(){
return id;
}
</code></pre>

This is the proper way to use annotation for uuid generators in Hibernate 5.0.11.FINAL.

Note: IT is deprecated.

I'm using my uuid as following:

<pre><code>@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid")
@Column(name = "uuid", unique = true)
private String uuid;
</code></pre>

but I'm getting a smart Hibernate warning:

<blockquote>
 Using
 org.hibernate.id.UUIDHexGenerator
 which does not generate IETF RFC 4122
 compliant UUID values; consider using
 org.hibernate.id.UUIDGenerator instead
</blockquote>

So I want to switch to <code>org.hibernate.id.UUIDGenerator</code>, now my question is how should I tell it to Hibernate's generator. I saw some guy used it as a "hibernate-uuid" - so this is what I've tried, but with negative result:

<pre><code>@Id
@GeneratedValue(generator = "hibernate-uuid")
@GenericGenerator(name = "hibernate-uuid", strategy = "hibernate-uuid")
@Column(name = "uuid", unique = true)
private String uuid;
</code></pre>

Using Hibernate UUIDGenerator via annotations

PostgreSQL

数据库

MySQL

Java

我使用我的uuid如下所示：@Id@GeneratedValue(generator = "uuid")@GenericGenerator(name = "uuid", strategy = "uuid")@Column(name = "uuid", unique = true)private String uuid;但是我得到了一个聪明的休眠警告：使用不生成符合IETF RFC4122的UUID

问通过注释使用Hibernate UUIDGenerator
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回答 8

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问通过注释使用Hibernate UUIDGenerator
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