criteria用法

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---

org.hibernate 
Interface Criteria

All Superinterfaces:

CriteriaSpecification

All 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 King

See Also:

Session.createCriteria(java.lang.Class), Restrictions, Projections, Order, Criterion, Projection, a disconnected version of this API

---

Field Summary

 

Fields inherited from interface org.hibernate.criterion.CriteriaSpecification

ALIAS_TO_ENTITY_MAP, DISTINCT_ROOT_ENTITY, FULL_JOIN, INNER_JOIN, LEFT_JOIN, PROJECTION, ROOT_ALIAS, ROOT_ENTITY

 

Method Summary
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

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 path

mode - The fetch mode for the referenced association

Returns:

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 applied

Returns:

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 applied

Returns:

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 path

alias - 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 path

alias - 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 path

alias - 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 path

Returns:

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 path

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)
                        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 path

alias - 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 path

alias - 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 path

alias - 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 apply

Returns:

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 results

Returns:

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 0

Returns:

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 mode

Throws:

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 mode

See 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 size

Returns:

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 cache

Returns:

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 string

Returns:

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 null

Throws:

HibernateException - if there is more than one matching result