有大量属性能用来控制Hibernate在运行期的行为. 它们都是可选的, 并拥有适当的默认值.
Warning: some of these properties are "system-level" only. System-level properties can be set only via java -Dproperty=value
or hibernate.properties
. They may not be set by the other techniques described above.
表 3.3. Hibernate配置属性
属性名 | 用途 |
---|---|
hibernate.dialect | The classname of a Hibernate org.hibernate.dialect.Dialect which allows Hibernate to generate SQL optimized for a particular relational database.
eg. In most cases Hibernate will actually be able to chose the correct |
hibernate.show_sql | Write all SQL statements to console. This is an alternative to setting the log category org.hibernate.SQL to debug .
eg. |
hibernate.format_sql | Pretty print the SQL in the log and console.
eg. |
hibernate.default_schema | Qualify unqualified table names with the given schema/tablespace in generated SQL.
eg. |
hibernate.default_catalog | Qualify unqualified table names with the given catalog in generated SQL.
eg. |
hibernate.session_factory_name | The org.hibernate.SessionFactory will be automatically bound to this name in JNDI after it has been created.
eg. |
hibernate.max_fetch_depth | Set a maximum "depth" for the outer join fetch tree for single-ended associations (one-to-one, many-to-one). A 0 disables default outer join fetching.
取值 建议在 |
hibernate.default_batch_fetch_size | Set a default size for Hibernate batch fetching of associations.
取值 建议的取值为 |
hibernate.default_entity_mode | Set a default mode for entity representation for all sessions opened from this SessionFactory
取值 |
hibernate.order_updates | Force Hibernate to order SQL updates by the primary key value of the items being updated. This will result in fewer transaction
deadlocks in highly concurrent systems.
eg. |
hibernate.generate_statistics | If enabled, Hibernate will collect statistics useful for performance tuning.
eg. |
hibernate.use_identifer_rollback | If enabled, generated identifier properties will be reset to default values when objects are deleted.
eg. |
hibernate.use_sql_comments | If turned on, Hibernate will generate comments inside the SQL, for easier debugging, defaults to false .
eg. |
表 3.4. Hibernate JDBC和连接(connection)属性
属性名 | 用途 |
---|---|
hibernate.jdbc.fetch_size | A non-zero value determines the JDBC fetch size (calls Statement.setFetchSize() ).
|
hibernate.jdbc.batch_size | A non-zero value enables use of JDBC2 batch updates by Hibernate.
取值 建议取 |
hibernate.jdbc.batch_versioned_data | Set this property to true if your JDBC driver returns correct row counts from executeBatch() (it is usually safe to turn this option on). Hibernate will then use batched DML for automatically versioned data. Defaults
to false .
eg. |
hibernate.jdbc.factory_class | Select a custom org.hibernate.jdbc.Batcher . Most applications will not need this configuration property.
eg. |
hibernate.jdbc.use_scrollable_resultset | Enables use of JDBC2 scrollable resultsets by Hibernate. This property is only necessary when using user supplied JDBC connections,
Hibernate uses connection metadata otherwise.
eg. |
hibernate.jdbc.use_streams_for_binary | Use streams when writing/reading binary or serializable types to/from JDBC. *system-level property*
eg. |
hibernate.jdbc.use_get_generated_keys | Enable use of JDBC3 PreparedStatement.getGeneratedKeys() to retrieve natively generated keys after insert. Requires JDBC3+ driver and JRE1.4+, set to false if your driver has problems
with the Hibernate identifier generators. By default, tries to determine the driver capabilities using connection metadata.
eg. |
hibernate.connection.provider_class | The classname of a custom org.hibernate.connection.ConnectionProvider which provides JDBC connections to Hibernate.
eg. |
hibernate.connection.isolation | Set the JDBC transaction isolation level. Check java.sql.Connection for meaningful values but note that most databases do not support all isolation levels and some define additional, non-standard
isolations.
eg. |
hibernate.connection.autocommit | Enables autocommit for JDBC pooled connections (not recommended).
eg. |
hibernate.connection.release_mode | Specify when Hibernate should release JDBC connections. By default, a JDBC connection is held until the session is explicitly
closed or disconnected. For an application server JTA datasource, you should use after_statement to aggressively release connections after every JDBC call. For a non-JTA connection, it often makes sense to release the
connection at the end of each transaction, by using after_transaction . auto will choose after_statement for the JTA and CMT transaction strategies and after_transaction for the JDBC transaction strategy.
eg. Note that this setting only affects |
hibernate.connection.<propertyName> | Pass the JDBC property <propertyName> to DriverManager.getConnection() .
|
hibernate.jndi.<propertyName> | Pass the property <propertyName> to the JNDI InitialContextFactory .
|
表 3.5. Hibernate缓存属性
属性名 | 用途 |
---|---|
hibernate.cache.provider_class
|
The classname of a custom CacheProvider .
eg. |
hibernate.cache.use_minimal_puts
|
Optimize second-level cache operation to minimize writes, at the cost of more frequent reads. This setting is most useful
for clustered caches and, in Hibernate3, is enabled by default for clustered cache implementations.
eg. |
hibernate.cache.use_query_cache
|
Enable the query cache, individual queries still have to be set cachable.
eg. |
hibernate.cache.use_second_level_cache
|
May be used to completely disable the second level cache, which is enabled by default for classes which specify a <cache> mapping.
eg. |
hibernate.cache.query_cache_factory
|
The classname of a custom QueryCache interface, defaults to the built-in StandardQueryCache .
eg. |
hibernate.cache.region_prefix
|
A prefix to use for second-level cache region names.
eg. |
hibernate.cache.use_structured_entries
|
Forces Hibernate to store data in the second-level cache in a more human-friendly format.
eg. |
表 3.6. Hibernate事务属性
属性名 | 用途 |
---|---|
hibernate.transaction.factory_class
|
The classname of a TransactionFactory to use with Hibernate Transaction API (defaults to JDBCTransactionFactory ).
eg. |
jta.UserTransaction
|
A JNDI name used by JTATransactionFactory to obtain the JTA UserTransaction from the application server.
eg. |
hibernate.transaction.manager_lookup_class
|
The classname of a TransactionManagerLookup - required when JVM-level caching is enabled or when using hilo generator in a JTA environment.
eg. |
hibernate.transaction.flush_before_completion
|
If enabled, the session will be automatically flushed during the before completion phase of the transaction. Built-in and
automatic session context management is preferred, see 第 2.5 节 “上下文相关的(Contextual)Session”.
eg. |
hibernate.transaction.auto_close_session
|
If enabled, the session will be automatically closed during the after completion phase of the transaction. Built-in and utomatic
session context management is preferred, see 第 2.5 节 “上下文相关的(Contextual)Session”.
eg. |
表 3.7. 其他属性
属性名 | 用途 |
---|---|
hibernate.current_session_context_class
|
Supply a (custom) strategy for the scoping of the "current" Session . See 第 2.5 节 “上下文相关的(Contextual)Session” for more information about the built-in strategies.
eg. |
hibernate.query.factory_class
|
Chooses the HQL parser implementation.
eg. |
hibernate.query.substitutions
|
Mapping from tokens in Hibernate queries to SQL tokens (tokens might be function or literal names, for example).
eg. |
hibernate.hbm2ddl.auto
|
Automatically validate or export schema DDL to the database when the SessionFactory is created. With create-drop , the database schema will be dropped when the SessionFactory is closed explicitly.
eg. |
hibernate.cglib.use_reflection_optimizer
|
Enables use of CGLIB instead of runtime reflection (System-level property). Reflection can sometimes be useful when troubleshooting,
note that Hibernate always requires CGLIB even if you turn off the optimizer. You can not set this property in hibernate.cfg.xml .
eg. |
你应当总是为你的数据库将hibernate.dialect
属性设置成正确的 org.hibernate.dialect.Dialect
子类. 如果你指定一种方言, Hibernate将为上面列出的一些属性使用合理的默认值, 为你省去了手工指定它们的功夫.
表 3.8. Hibernate SQL方言 (hibernate.dialect
)
RDBMS | Dialect |
---|---|
DB2 | org.hibernate.dialect.DB2Dialect |
DB2 AS/400 | org.hibernate.dialect.DB2400Dialect |
DB2 OS390 | org.hibernate.dialect.DB2390Dialect |
PostgreSQL | org.hibernate.dialect.PostgreSQLDialect |
MySQL | org.hibernate.dialect.MySQLDialect |
MySQL with InnoDB | org.hibernate.dialect.MySQLInnoDBDialect |
MySQL with MyISAM | org.hibernate.dialect.MySQLMyISAMDialect |
Oracle (any version) | org.hibernate.dialect.OracleDialect |
Oracle 9i/10g | org.hibernate.dialect.Oracle9Dialect |
Sybase | org.hibernate.dialect.SybaseDialect |
Sybase Anywhere | org.hibernate.dialect.SybaseAnywhereDialect |
Microsoft SQL Server | org.hibernate.dialect.SQLServerDialect |
SAP DB | org.hibernate.dialect.SAPDBDialect |
Informix | org.hibernate.dialect.InformixDialect |
HypersonicSQL | org.hibernate.dialect.HSQLDialect |
Ingres | org.hibernate.dialect.IngresDialect |
Progress | org.hibernate.dialect.ProgressDialect |
Mckoi SQL | org.hibernate.dialect.MckoiDialect |
Interbase | org.hibernate.dialect.InterbaseDialect |
Pointbase | org.hibernate.dialect.PointbaseDialect |
FrontBase | org.hibernate.dialect.FrontbaseDialect |
Firebird | org.hibernate.dialect.FirebirdDialect |
如果你的数据库支持ANSI, Oracle或Sybase风格的外连接, 外连接抓取通常能通过限制往返数据库次数 (更多的工作交由数据库自己来完成)来提高效率. 外连接抓取允许在单个SELECT
SQL语句中, 通过many-to-one, one-to-many, many-to-many和one-to-one关联获取连接对象的整个对象图.
将hibernate.max_fetch_depth
设为0
能在全局 范围内禁止外连接抓取. 设为1
或更高值能启用one-to-one和many-to-oneouter关联的外连接抓取, 它们通过 fetch="join"
来映射.
参见第 19.1 节 “抓取策略(Fetching strategies)”获得更多信息.
Oracle限制那些通过JDBC驱动传输的字节
数组的数目. 如果你希望使用二进值 (binary)
或 可序列化的 (serializable)
类型的大对象, 你应该开启 hibernate.jdbc.use_streams_for_binary
属性. 这是系统级属性.
以hibernate.cache
为前缀的属性允许你在Hibernate中,使用进程或群集范围内的二级缓存系统. 参见第 19.2 节 “二级缓存(The Second Level Cache)”获取更多的详情.
你可以使用hibernate.query.substitutions
在Hibernate中定义新的查询符号. 例如:
hibernate.query.substitutions true=1, false=0
将导致符号true
和false
在生成的SQL中被翻译成整数常量.
hibernate.query.substitutions toLowercase=LOWER
将允许你重命名SQL中的LOWER
函数.