criteria用法
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org.hibernate
Interface Criteria
All Superinterfaces:CriteriaSpecificationAll Known Implementing Classes:CriteriaImpl, CriteriaImpl.Subcriteria
public interface Criteriaextends CriteriaSpecification
Criteria is a simplified API for retrieving entities by composing Criterion objects. This is a very convenient approach for functionality like “search” screens where there is a variable number of conditions to be placed upon the result set.
The Session is a factory for Criteria. Criterion instances are usually obtained via the factory methods on Restrictions. eg.
List cats = session.createCriteria(Cat.class) .add( Restrictions.like("name", "Iz%") ) .add( Restrictions.gt( "weight", new Float(minWeight) ) ) .addOrder( Order.asc("age") ) .list();
You may navigate associations using createAlias() or createCriteria().
List cats = session.createCriteria(Cat.class) .createCriteria("kittens") .add( Restrictions.like("name", "Iz%") ) .list();
List cats = session.createCriteria(Cat.class) .createAlias("kittens", "kit") .add( Restrictions.like("kit.name", "Iz%") ) .list();
You may specify projection and aggregation using Projection instances obtained via the factory methods on Projections.
List cats = session.createCriteria(Cat.class) .setProjection( Projections.projectionList() .add( Projections.rowCount() ) .add( Projections.avg("weight") ) .add( Projections.max("weight") ) .add( Projections.min("weight") ) .add( Projections.groupProperty("color") ) ) .addOrder( Order.asc("color") ) .list();
Author:Gavin KingSee Also:Session.createCriteria(java.lang.Class)
, Restrictions
, Projections
, Order
, Criterion
, Projection
, a disconnected version of this API
Field Summary |
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Fields inherited from interface org.hibernate.criterion.CriteriaSpecification |
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ALIAS_TO_ENTITY_MAP, DISTINCT_ROOT_ENTITY, FULL_JOIN, INNER_JOIN, LEFT_JOIN, PROJECTION, ROOT_ALIAS, ROOT_ENTITY |
Method Summary | |
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Criteria |
add(Criterion criterion) Add a restriction to constrain the results to be retrieved. |
Criteria |
addOrder(Order order) Add an ordering to the result set. |
Criteria |
createAlias(String associationPath, String alias) Join an association, assigning an alias to the joined association. |
Criteria |
createAlias(String associationPath, String alias, int joinType) Join an association using the specified join-type, assigning an alias to the joined association. |
Criteria |
createAlias(String associationPath, String alias, int joinType, Criterion withClause) Join an association using the specified join-type, assigning an alias to the joined association. |
Criteria |
createCriteria(String associationPath) Create a new Criteria, “rooted” at the associated entity. |
Criteria |
createCriteria(String associationPath, int joinType) Create a new Criteria, “rooted” at the associated entity, using the specified join type. |
Criteria |
createCriteria(String associationPath, String alias) Create a new Criteria, “rooted” at the associated entity, assigning the given alias. |
Criteria |
createCriteria(String associationPath, String alias, int joinType) Create a new Criteria, “rooted” at the associated entity, assigning the given alias and using the specified join type. |
Criteria |
createCriteria(String associationPath, String alias, int joinType, Criterion withClause) Create a new Criteria, “rooted” at the associated entity, assigning the given alias and using the specified join type. |
String |
getAlias() Get the alias of the entity encapsulated by this criteria instance. |
boolean |
isReadOnly() Should entities and proxies loaded by this Criteria be put in read-only mode? If the read-only/modifiable setting was not initialized, then the default read-only/modifiable setting for the persistence context is returned instead. |
boolean |
isReadOnlyInitialized() Was the read-only/modifiable mode explicitly initialized? |
List |
list() Get the results. |
ScrollableResults |
scroll() Get the results as an instance of ScrollableResults |
ScrollableResults |
scroll(ScrollMode scrollMode) Get the results as an instance of ScrollableResults based on the given scroll mode. |
Criteria |
setCacheable(boolean cacheable) Enable caching of this query result, provided query caching is enabled for the underlying session factory. |
Criteria |
setCacheMode(CacheMode cacheMode) Override the cache mode for this particular query. |
Criteria |
setCacheRegion(String cacheRegion) Set the name of the cache region to use for query result caching. |
Criteria |
setComment(String comment) Add a comment to the generated SQL. |
Criteria |
setFetchMode(String associationPath, FetchMode mode) Specify an association fetching strategy for an association or a collection of values. |
Criteria |
setFetchSize(int fetchSize) Set a fetch size for the underlying JDBC query. |
Criteria |
setFirstResult(int firstResult) Set the first result to be retrieved. |
Criteria |
setFlushMode(FlushMode flushMode) Override the flush mode for this particular query. |
Criteria |
setLockMode(LockMode lockMode) Set the lock mode of the current entity |
Criteria |
setLockMode(String alias, LockMode lockMode) Set the lock mode of the aliased entity |
Criteria |
setMaxResults(int maxResults) Set a limit upon the number of objects to be retrieved. |
Criteria |
setProjection(Projection projection) Used to specify that the query results will be a projection (scalar in nature). |
Criteria |
setReadOnly(boolean readOnly) Set the read-only/modifiable mode for entities and proxies loaded by this Criteria. |
Criteria |
setResultTransformer(ResultTransformer resultTransformer) Set a strategy for handling the query results. |
Criteria |
setTimeout(int timeout) Set a timeout for the underlying JDBC query. |
Object |
uniqueResult() Convenience method to return a single instance that matches the query, or null if the query returns no results. |
Method Detail |
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getAlias
String getAlias()
Get the alias of the entity encapsulated by this criteria instance.
Returns:The alias for the encapsulated entity.
setProjection
Criteria setProjection(Projection projection)
Used to specify that the query results will be a projection (scalar in nature). Implicitly specifies the CriteriaSpecification.PROJECTION
result transformer.
The individual components contained within the given projection
determines the overall “shape” of the query result.
Parameters:projection
– The projection representing the overall “shape” of the query results.Returns:this (for method chaining)
add
Criteria add(Criterion criterion)
Add a restriction
to constrain the results to be retrieved.
Parameters:criterion
– The criterion
object representing the restriction to be applied.Returns:this (for method chaining)
addOrder
Criteria addOrder(Order order)
Add an ordering
to the result set.
Parameters:order
– The order
object representing an ordering to be applied to the results.Returns:this (for method chaining)
setFetchMode
Criteria setFetchMode(String associationPath, FetchMode mode) throws HibernateException
Specify an association fetching strategy for an association or a collection of values.
Parameters:associationPath
– a dot seperated property pathmode
– The fetch mode for the referenced associationReturns:this (for method chaining)Throws:HibernateException
– Indicates a problem applying the given fetch mode
setLockMode
Criteria setLockMode(LockMode lockMode)
Set the lock mode of the current entity
Parameters:lockMode
– The lock mode to be appliedReturns:this (for method chaining)
setLockMode
Criteria setLockMode(String alias, LockMode lockMode)
Set the lock mode of the aliased entity
Parameters:alias
– The previously assigned alias representing the entity to which the given lock mode should apply.lockMode
– The lock mode to be appliedReturns:this (for method chaining)
createAlias
Criteria createAlias(String associationPath, String alias) throws HibernateException
Join an association, assigning an alias to the joined association.
Functionally equivalent to createAlias(String, String, int)
using CriteriaSpecification.INNER_JOIN
for the joinType.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).Returns:this (for method chaining)Throws:HibernateException
– Indicates a problem creating the sub criteria
createAlias
Criteria createAlias(String associationPath, String alias, int joinType) throws HibernateException
Join an association using the specified join-type, assigning an alias to the joined association.
The joinType is expected to be one of CriteriaSpecification.INNER_JOIN
(the default), CriteriaSpecification.FULL_JOIN
, or CriteriaSpecification.LEFT_JOIN
.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).joinType
– The type of join to use.Returns:this (for method chaining)Throws:HibernateException
– Indicates a problem creating the sub criteria
createAlias
Criteria createAlias(String associationPath, String alias, int joinType, Criterion withClause) throws HibernateException
Join an association using the specified join-type, assigning an alias to the joined association.
The joinType is expected to be one of CriteriaSpecification.INNER_JOIN
(the default), CriteriaSpecification.FULL_JOIN
, or CriteriaSpecification.LEFT_JOIN
.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).joinType
– The type of join to use.withClause
– The criteria to be added to the join condition (ON clause)Returns:this (for method chaining)Throws:HibernateException
– Indicates a problem creating the sub criteria
createCriteria
Criteria createCriteria(String associationPath) throws HibernateException
Create a new Criteria, “rooted” at the associated entity.
Functionally equivalent to createCriteria(String, int)
using CriteriaSpecification.INNER_JOIN
for the joinType.
Parameters:associationPath
– A dot-seperated property pathReturns:the created “sub criteria”Throws:HibernateException
– Indicates a problem creating the sub criteria
createCriteria
Criteria createCriteria(String associationPath, int joinType) throws HibernateException
Create a new Criteria, “rooted” at the associated entity, using the specified join type.
Parameters:associationPath
– A dot-seperated property pathjoinType
– The type of join to use.Returns:the created “sub criteria”Throws:HibernateException
– Indicates a problem creating the sub criteria
createCriteria
Criteria createCriteria(String associationPath, String alias) throws HibernateException
Create a new Criteria, “rooted” at the associated entity, assigning the given alias.
Functionally equivalent to createCriteria(String, String, int)
using CriteriaSpecification.INNER_JOIN
for the joinType.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).Returns:the created “sub criteria”Throws:HibernateException
– Indicates a problem creating the sub criteria
createCriteria
Criteria createCriteria(String associationPath, String alias, int joinType) throws HibernateException
Create a new Criteria, “rooted” at the associated entity, assigning the given alias and using the specified join type.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).joinType
– The type of join to use.Returns:the created “sub criteria”Throws:HibernateException
– Indicates a problem creating the sub criteria
createCriteria
Criteria createCriteria(String associationPath, String alias, int joinType, Criterion withClause) throws HibernateException
Create a new Criteria, “rooted” at the associated entity, assigning the given alias and using the specified join type.
Parameters:associationPath
– A dot-seperated property pathalias
– The alias to assign to the joined association (for later reference).joinType
– The type of join to use.withClause
– The criteria to be added to the join condition (ON clause)Returns:the created “sub criteria”Throws:HibernateException
– Indicates a problem creating the sub criteria
setResultTransformer
Criteria setResultTransformer(ResultTransformer resultTransformer)
Set a strategy for handling the query results. This determines the “shape” of the query result.
Parameters:resultTransformer
– The transformer to applyReturns:this (for method chaining)See Also:CriteriaSpecification.ROOT_ENTITY
, CriteriaSpecification.DISTINCT_ROOT_ENTITY
, CriteriaSpecification.ALIAS_TO_ENTITY_MAP
, CriteriaSpecification.PROJECTION
setMaxResults
Criteria setMaxResults(int maxResults)
Set a limit upon the number of objects to be retrieved.
Parameters:maxResults
– the maximum number of resultsReturns:this (for method chaining)
setFirstResult
Criteria setFirstResult(int firstResult)
Set the first result to be retrieved.
Parameters:firstResult
– the first result to retrieve, numbered from 0Returns:this (for method chaining)
isReadOnlyInitialized
boolean isReadOnlyInitialized()
Was the read-only/modifiable mode explicitly initialized?
Returns:true, the read-only/modifiable mode was explicitly initialized; false, otherwise.See Also:setReadOnly(boolean)
isReadOnly
boolean isReadOnly()
Should entities and proxies loaded by this Criteria be put in read-only mode? If the read-only/modifiable setting was not initialized, then the default read-only/modifiable setting for the persistence context is returned instead.
Returns:true, entities and proxies loaded by the criteria will be put in read-only mode false, entities and proxies loaded by the criteria will be put in modifiable modeThrows:IllegalStateException
– if isReadOnlyInitialized()
returns false
and this Criteria is not associated with a session.See Also:setReadOnly(boolean)
, The read-only/modifiable setting has no impact on entities/proxies returned by the Criteria that existed in the session before the Criteria was executed.
, isReadOnlyInitialized()
setReadOnly
Criteria setReadOnly(boolean readOnly)
Set the read-only/modifiable mode for entities and proxies loaded by this Criteria. This setting overrides the default setting for the persistence context.
Parameters:readOnly
– true, entities and proxies loaded by the criteria will be put in read-only mode false, entities and proxies loaded by the criteria will be put in modifiable modeSee Also:To set the default read-only/modifiable setting used for entities and proxies that are loaded into the session:
, PersistenceContext.setDefaultReadOnly(boolean)
, Read-only entities are not dirty-checked and snapshots of persistent state are not maintained. Read-only entities can be modified, but changes are not persisted. When a proxy is initialized, the loaded entity will have the same read-only/modifiable setting as the uninitialized proxy has, regardless of the session's current setting. The read-only/modifiable setting has no impact on entities/proxies returned by the criteria that existed in the session before the criteria was executed.
setFetchSize
Criteria setFetchSize(int fetchSize)
Set a fetch size for the underlying JDBC query.
Parameters:fetchSize
– the fetch sizeReturns:this (for method chaining)See Also:Statement.setFetchSize(int)
setTimeout
Criteria setTimeout(int timeout)
Set a timeout for the underlying JDBC query.
Parameters:timeout
– The timeout value to apply.Returns:this (for method chaining)See Also:Statement.setQueryTimeout(int)
setCacheable
Criteria setCacheable(boolean cacheable)
Enable caching of this query result, provided query caching is enabled for the underlying session factory.
Parameters:cacheable
– Should the result be considered cacheable; default is to not cache (false).Returns:this (for method chaining)
setCacheRegion
Criteria setCacheRegion(String cacheRegion)
Set the name of the cache region to use for query result caching.
Parameters:cacheRegion
– the name of a query cache region, or null for the default query cacheReturns:this (for method chaining)See Also:setCacheable(boolean)
setComment
Criteria setComment(String comment)
Add a comment to the generated SQL.
Parameters:comment
– a human-readable stringReturns:this (for method chaining)
setFlushMode
Criteria setFlushMode(FlushMode flushMode)
Override the flush mode for this particular query.
Parameters:flushMode
– The flush mode to use.Returns:this (for method chaining)
setCacheMode
Criteria setCacheMode(CacheMode cacheMode)
Override the cache mode for this particular query.
Parameters:cacheMode
– The cache mode to use.Returns:this (for method chaining)
list
List list() throws HibernateException
Get the results.
Returns:The list of matched query results.Throws:HibernateException
– Indicates a problem either translating the criteria to SQL, exeucting the SQL or processing the SQL results.
scroll
ScrollableResults scroll() throws HibernateException
Get the results as an instance of ScrollableResults
Returns:The ScrollableResults
representing the matched query results.Throws:HibernateException
– Indicates a problem either translating the criteria to SQL, exeucting the SQL or processing the SQL results.
scroll
ScrollableResults scroll(ScrollMode scrollMode) throws HibernateException
Get the results as an instance of ScrollableResults
based on the given scroll mode.
Parameters:scrollMode
– Indicates the type of underlying database cursor to request.Returns:The ScrollableResults
representing the matched query results.Throws:HibernateException
– Indicates a problem either translating the criteria to SQL, exeucting the SQL or processing the SQL results.
uniqueResult
Object uniqueResult() throws HibernateException
Convenience method to return a single instance that matches the query, or null if the query returns no results.
Returns:the single result or nullThrows:HibernateException
– if there is more than one matching result