哈希映射不保留插入顺序。 的例子。Hashmap 如果您正在插入键作为

1  3
5  9
4   6
7   15
3   10

它可以存储为

4  6
5  9
3  10
1  3
7  15

链接Hashmap保留插入顺序。

的例子。 如果您正在插入键

1  3
5  9
4   6
7   15
3   10

它将存储为

1  3
5  9
4   6
7   15
3   10

和我们插入的一样。

树映射以键的递增顺序存储山谷。 的例子。 如果您正在插入键

1  3
5  9
4   6
7   15
3   10

它将存储为

1  3
3  10
4   6
5   9
7   15

@Amit: SortedMap is an interface whereas TreeMap is a class which implements the SortedMap interface. That means if follows the protocol which SortedMap asks its implementers to do. A tree unless implemented as search tree, can't give you ordered data because tree can be any kind of tree. So to make TreeMap work like Sorted order, it implements SortedMap ( e.g, Binary Search Tree - BST, balanced BST like AVL and R-B Tree , even Ternary Search Tree - mostly used for iterative searches in ordered way ).

public class TreeMap<K,V>
extends AbstractMap<K,V>
implements SortedMap<K,V>, Cloneable, Serializable

在坚果壳 HashMap:给出O(1)的数据，没有排序

TreeMap:给出O(log N)，以2为底的数据。使用有序键

LinkedHashMap:是具有链表(想想索引- skiplist)功能的哈希表，以插入树的方式存储数据。最适合实现LRU(最近最少使用)。

虽然这里有很多很好的答案，但我想给出我自己的表，描述与Java 11绑定的各种Map实现。

我们可以在图表中看到这些差异:

HashMap is the general-purpose Map commonly used when you have no special needs. LinkedHashMap extends HashMap, adding this behavior: Maintains an order, the order in which the entries were originally added. Altering the value for key-value entry does not alter its place in the order. TreeMap too maintains an order, but uses either (a) the “natural” order, meaning the value of the compareTo method on the key objects defined on the Comparable interface, or (b) invokes a Comparator implementation you provide. TreeMap implements both the SortedMap interface, and its successor, the NavigableMap interface. NULLs: TreeMap does not allow a NULL as the key, while HashMap & LinkedHashMap do. All three allow NULL as the value. HashTable is legacy, from Java 1. Supplanted by the ConcurrentHashMap class. Quoting the Javadoc: ConcurrentHashMap obeys the same functional specification as Hashtable, and includes versions of methods corresponding to each method of Hashtable.

HashMap 可以包含一个空键。

HashMap没有秩序。

TreeMap

TreeMap不能包含任何空键。

TreeMap保持升序。

LinkedHashMap

LinkedHashMap可用于维护插入顺序，即键被插入到Map中，也可用于维护访问顺序，即键被访问。

例子::

1) HashMap map = new HashMap();

    map.put(null, "Kamran");
    map.put(2, "Ali");
    map.put(5, "From");
    map.put(4, "Dir");`enter code here`
    map.put(3, "Lower");
    for (Map.Entry m : map.entrySet()) {
        System.out.println(m.getKey() + "  " + m.getValue());
    } 

2) TreeMap map = new TreeMap();

    map.put(1, "Kamran");
    map.put(2, "Ali");
    map.put(5, "From");
    map.put(4, "Dir");
    map.put(3, "Lower");
    for (Map.Entry m : map.entrySet()) {
        System.out.println(m.getKey() + "  " + m.getValue());
    }

3) LinkedHashMap map = new LinkedHashMap();

    map.put(1, "Kamran");
    map.put(2, "Ali");
    map.put(5, "From");
    map.put(4, "Dir");
    map.put(3, "Lower");
    for (Map.Entry m : map.entrySet()) {
        System.out.println(m.getKey() + "  " + m.getValue());
    }

HashMap

它有一对值(键，值) 禁止复制键值 无序的无序 它允许一个空键和多个空值

哈希表

和哈希映射一样 它不允许空键和空值

LinkedHashMap

它是map实现的有序版本 基于链表和哈希数据结构

TreeMap

有序和排序版本 基于哈希数据结构

我更喜欢视觉呈现: