Spring tool class -- the use of CollectionUtils

Original URL: Spring tool class -- the use of CollectionUtils_IT sharp knife unsheathed blog-CSDN blog

Introduction

This article introduces the use of Spring's CollectionUtils.

The role of the CollectionUtils tool class: to operate Collection, such as: List, Set.

judgment

method	effect
static boolean  isEmpty (Collection<?> collection)	Check if the collection is empty.
static boolean  isEmpty(Map<?,?> map)	Determine whether the Map is empty
static boolean  containsInstance (     Collection<?> collection,      Object element )	Determine whether a collection contains an object
static boolean  contains (     Iterator<?> iterator,      Object element )	Use an iterator to determine whether an object is in the collection.
static boolean  containsAny (     Collection<?> source,      Collection<?> candidates )	Determine whether a collection contains any of some objects.
static boolean  hasUniqueObject (Collection<?> collection)	Determine whether each element in the collection is unique. That is, there are no duplicate elements in the collection.

add to collection

method	effect
static <E> void mergeArrayIntoCollection (     Object array,      Collection<E> collection )	Add all elements in the array to the set.
static <K,V> void mergePropertiesIntoMap (     Properties props,      Map<K,V> map )	Add the key-value pairs in Properties to Map

find in collection

method	effect
static <T> T lastElement (List<T> list)	Returns the last element in the List.
static <T> T lastElement (Set<T> set)	Returns the last element in the Set.
static <E> E findFirstMatch (     Collection<?> source,      Collection<E> candidates )	Returns the first element of candidates present in source.
static <T> T findValueOfType (     Collection<?> collection,      Class<T> type )	Returns the elements of the specified type in the collection.
static Object findValueOfType (     Collection<?> collection,      Class<?>[] types )	Returns the elements of the specified type in the collection. If the first type is not found, the second type is looked for, and so on.
static Class<?> findCommonElementType (Collection<?> collection)	Returns the type of the elements in the collection