java.lang.Object
- org.springframework.dao.support.DataAccessUtils

```
public abstract class DataAccessUtils
extends Object
```
Miscellaneous utility methods for DAO implementations. Useful with any data access technology.
从以下版本开始:
1.0.2
作者:
Juergen Hoeller

构造器概要
构造器
构造器说明
DataAccessUtils()

方法概要

所有方法静态方法具体方法
修饰符和类型	方法	说明
`static int`	`intResult(Collection<?> results)`	Return a unique int result from the given Collection.
`static long`	`longResult(Collection<?> results)`	Return a unique long result from the given Collection.
`static <T> T`	`nullableSingleResult(Collection<T> results)`	Return a single result object from the given Collection.
`static <T> T`	`objectResult(Collection<?> results, Class<T> requiredType)`	Return a unique result object from the given Collection.
`static <T> T`	`requiredSingleResult(Collection<T> results)`	Return a single result object from the given Collection.
`static <T> T`	`requiredUniqueResult(Collection<T> results)`	Return a unique result object from the given Collection.
`static <T> T`	`singleResult(Collection<T> results)`	Return a single result object from the given Collection.
`static RuntimeException`	`translateIfNecessary(RuntimeException rawException, PersistenceExceptionTranslator pet)`	Return a translated exception if this is appropriate, otherwise return the given exception as-is.
`static <T> T`	`uniqueResult(Collection<T> results)`	Return a unique result object from the given Collection.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - DataAccessUtils
```
public DataAccessUtils()
```
- 方法详细资料
  - singleResult
```
@Nullable
public static <T> T singleResult(@Nullable
                                 Collection<T> results)
                          throws IncorrectResultSizeDataAccessException
```
    Return a single result object from the given Collection.
    Returns null if 0 result objects found; throws an exception if more than 1 element found.
    参数:
    results - the result Collection (can be null)
    返回:
    the single result object, or null if none
    抛出:
    IncorrectResultSizeDataAccessException - if more than one element has been found in the given Collection
  - requiredSingleResult
```
public static <T> T requiredSingleResult(@Nullable
                                         Collection<T> results)
                                  throws IncorrectResultSizeDataAccessException
```
    Return a single result object from the given Collection.
    Throws an exception if 0 or more than 1 element found.
    参数:
    results - the result Collection (can be null but is not expected to contain null elements)
    返回:
    the single result object
    抛出:
    IncorrectResultSizeDataAccessException - if more than one element has been found in the given Collection
    EmptyResultDataAccessException - if no element at all has been found in the given Collection
  - nullableSingleResult
```
@Nullable
public static <T> T nullableSingleResult(@Nullable
                                         Collection<T> results)
                                  throws IncorrectResultSizeDataAccessException
```
    Return a single result object from the given Collection.
    Throws an exception if 0 or more than 1 element found.
    参数:
    results - the result Collection (can be null and is also expected to contain null elements)
    返回:
    the single result object
    抛出:
    IncorrectResultSizeDataAccessException - if more than one element has been found in the given Collection
    EmptyResultDataAccessException - if no element at all has been found in the given Collection
    从以下版本开始:
    5.0.2
  - uniqueResult
```
@Nullable
public static <T> T uniqueResult(@Nullable
                                 Collection<T> results)
                          throws IncorrectResultSizeDataAccessException
```
    Return a unique result object from the given Collection.
    Returns null if 0 result objects found; throws an exception if more than 1 instance found.
    参数:
    results - the result Collection (can be null)
    返回:
    the unique result object, or null if none
    抛出:
    IncorrectResultSizeDataAccessException - if more than one result object has been found in the given Collection
    另请参阅:
    CollectionUtils.hasUniqueObject(java.util.Collection<?>)
  - requiredUniqueResult
```
public static <T> T requiredUniqueResult(@Nullable
                                         Collection<T> results)
                                  throws IncorrectResultSizeDataAccessException
```
    Return a unique result object from the given Collection.
    Throws an exception if 0 or more than 1 instance found.
    参数:
    results - the result Collection (can be null but is not expected to contain null elements)
    返回:
    the unique result object
    抛出:
    IncorrectResultSizeDataAccessException - if more than one result object has been found in the given Collection
    EmptyResultDataAccessException - if no result object at all has been found in the given Collection
    另请参阅:
    CollectionUtils.hasUniqueObject(java.util.Collection<?>)
  - objectResult
```
public static <T> T objectResult(@Nullable
                                 Collection<?> results,
                                 @Nullable
                                 Class<T> requiredType)
                          throws IncorrectResultSizeDataAccessException,
                                 TypeMismatchDataAccessException
```
    Return a unique result object from the given Collection. Throws an exception if 0 or more than 1 result objects found, of if the unique result object is not convertible to the specified required type.
    参数:
    results - the result Collection (can be null but is not expected to contain null elements)
    返回:
    the unique result object
    抛出:
    IncorrectResultSizeDataAccessException - if more than one result object has been found in the given Collection
    EmptyResultDataAccessException - if no result object at all has been found in the given Collection
    TypeMismatchDataAccessException - if the unique object does not match the specified required type
  - intResult
```
public static int intResult(@Nullable
                            Collection<?> results)
                     throws IncorrectResultSizeDataAccessException,
                            TypeMismatchDataAccessException
```
    Return a unique int result from the given Collection. Throws an exception if 0 or more than 1 result objects found, of if the unique result object is not convertible to an int.
    参数:
    results - the result Collection (can be null but is not expected to contain null elements)
    返回:
    the unique int result
    抛出:
    IncorrectResultSizeDataAccessException - if more than one result object has been found in the given Collection
    EmptyResultDataAccessException - if no result object at all has been found in the given Collection
    TypeMismatchDataAccessException - if the unique object in the collection is not convertible to an int
  - longResult
```
public static long longResult(@Nullable
                              Collection<?> results)
                       throws IncorrectResultSizeDataAccessException,
                              TypeMismatchDataAccessException
```
    Return a unique long result from the given Collection. Throws an exception if 0 or more than 1 result objects found, of if the unique result object is not convertible to a long.
    参数:
    results - the result Collection (can be null but is not expected to contain null elements)
    返回:
    the unique long result
    抛出:
    IncorrectResultSizeDataAccessException - if more than one result object has been found in the given Collection
    EmptyResultDataAccessException - if no result object at all has been found in the given Collection
    TypeMismatchDataAccessException - if the unique object in the collection is not convertible to a long
  - translateIfNecessary
```
public static RuntimeException translateIfNecessary(RuntimeException rawException,
                                                    PersistenceExceptionTranslator pet)
```
    Return a translated exception if this is appropriate, otherwise return the given exception as-is.
    参数:
    rawException - an exception that we may wish to translate
    pet - the PersistenceExceptionTranslator to use to perform the translation
    返回:
    a translated persistence exception if translation is possible, or the raw exception if it is not

类 DataAccessUtils

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

DataAccessUtils

方法详细资料

singleResult

requiredSingleResult

nullableSingleResult

uniqueResult

requiredUniqueResult

objectResult

intResult

longResult

translateIfNecessary