Java Container Summary

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three points of knowledge1. iterators

1. Java.util.iterator+hashnext () Next () Remove ()
2. Java.lang.iterable+ rewrite iterator () returns an iterator (the container needs to use enhanced for foreach )

2. Comparator

1. Entity classes can be sorted Java.lang.comparable+compareto
2. Sort comparer (decoupling, coping with multiple collations) java.util.comparator+ overriding compare () method
   Container sort: list+collections.sort () method
   TreeSet, TreeMap

3. Generic type <>

Generic classes, generic methods, generic interfaces, generic erase, wildcard characters? Extends super, generics nesting

Six InterfacesCollection, Set, List, Map, Iterator, comparable Nine common classes(Add, delete, view + Traverse) 1. ArrayList:

The underlying is an array for viewing redundant modifications @**@

add(E e) 、addindex, E element) 、removeindex) 、remove(Object o) 、setindexindex)遍历：1、for+get  2、foreach  3、Iterator  4、ListIterator

2.LinkedList:

The bottom is the linked list, which is suitable for modifying the redundant view, the method of the chain head and the tail of the chain.

3.HashSet:

Elements cannot be duplicated, so require elements to override the Hashcode and Equals methods

add(E e)remove(Object o) 遍历：1、foreach  2、Iterator

4.TreeSet:

Elements can be sorted or provide a sort of business class

5.HASHMAP:

Key cannot be repeated must override Hashcode+equals method @**@

put(K key, V value)、Remove(Object key)、ContainsKey(Object key)、Containsvalue(Object value)Traversal: Gets the value:Values()、KeySet()+Get()、EntrySet()+GetValue()Get key:KeySet()、EntrySet()+GetKey()Get key and value:KeySet()+Get()、EntrySet()+GetKey()+GetValue()

6.Properties:

Resource profile relative path get file @**@

7.Hashtable:

Both key and value cannot be null thread safe, and the efficiency is relatively low

8.Stack: Stack 9.Collections: Tool class

Java Container Summary