Java LinkedHashMap深入分析源码
作者:AllenC6 发布时间:2022-07-31 03:05:43
一、LinkedHashMap的类继承关系
二、源码分析
1.自己对LinkedHashMap的理解
从继承关系上,我们看到LinkedHashMap继承了HashMap,它里面的增删改差遍历的逻辑都是使用的HashMap中的,但是LinkedHashMap比HashMap多了一个双向链,这个双向链是从第一个插入的元素开始按照插入顺序,连接起来,所以可以说LinkedHashMap是可以保证插入顺序的。
看图:这里就简单的给大家看一下这个链是啥样的,不画红黑树了
2.如何做到双向链的增删改查
(1).增
1).是在创建新节点的时候,把双向链连接起来,注意有两种节点一个是TreeNode一个普通Node
源码:
Node<K,V> newNode(int hash, K key, V value, Node<K,V> e) {
LinkedHashMap.Entry<K,V> p =
new LinkedHashMap.Entry<K,V>(hash, key, value, e);
linkNodeLast(p);
return p;
}
TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
TreeNode<K,V> p = new TreeNode<K,V>(hash, key, value, next);
linkNodeLast(p);
return p;
}
private void linkNodeLast(LinkedHashMap.Entry<K,V> p) {
LinkedHashMap.Entry<K,V> last = tail;
tail = p;
if (last == null)
head = p;
else {
p.before = last;
last.after = p;
}
}
static class Entry<K,V> extends HashMap.Node<K,V> {
Entry<K,V> before, after;
Entry(int hash, K key, V value, Node<K,V> next) {
super(hash, key, value, next);
}
}
代码太简单了,这里简单描述一下,就是添加新节点会创建Node,有两种Node:TreeNode和普通Node(注意这里多态的使用普通Node和LinedHashMap.Entry和TreeNode的关系看一下就明白了),在创建之后放到双向链最后面。
2).有好多人说了还有一个afterNodeInsertion方法,这个方法的名字就显示是在插入之后调用的,是不是在这个方法中也有修改链表的逻辑,我们来看这个方法
void afterNodeInsertion(boolean evict) { // possibly remove eldest
LinkedHashMap.Entry<K,V> first;
if (evict && (first = head) != null && removeEldestEntry(first)) {
K key = first.key;
removeNode(hash(key), key, null, false, true);
}
}
protected boolean removeEldestEntry(Map.Entry<K,V> eldest) {
return false;
}
看这个判断,有一个永远是false,也就是说如果我们不重写这个removeEldestEntry方法,那这个afterNodeInsertion方法里的逻辑永远不会执行,那这个玩意儿是干啥的呢,看逻辑是用来移除最早的头节点的,不知道为啥写着么一段,默认不会执行!!!
(2).删
void afterNodeRemoval(Node<K,V> e) { // unlink
LinkedHashMap.Entry<K,V> p =
(LinkedHashMap.Entry<K,V>)e, b = p.before, a = p.after; // b是当前节点的前一个节点,a是后一个节点
p.before = p.after = null; //先断开当前节点,把当前节点对上一个和下一个节点的引用置为空
if (b == null) //当前节点的前一个节点是null,说明当前节点是头节点,那去掉当前节点之后,当前节点的后一个节点成为了链第一个,
// 也就是头节点,当然有可能a也是null,那整个链就是空链,这种写法兼容了a也是null的情况
head = a;
else
b.after = a; //如果当前节点不是头节点,直接去掉当前节点,当前节点的前一个和后一个连起来
if (a == null) //如果当前节点的后一个节点是null,说明当前节点是尾节点,那把当前节点去掉后,当前节点的前一个节点成为了链的最后一个节点尾节点。
tail = b;
else
a.before = b;//如果当前节点不是尾节点,直接去掉当前节点,当前节点的前一个和后一个连起来
}
这个删除我们看一下在哪里调用的:
final Node<K,V> removeNode(int hash, Object key, Object value,
boolean matchValue, boolean movable) {
...
if (node != null && (!matchValue || (v = node.value) == value ||
(value != null && value.equals(v)))) {
if (node instanceof TreeNode)
((TreeNode<K,V>)node).removeTreeNode(this, tab, movable);
else if (node == p)
tab[index] = node.next;
else
p.next = node.next;
++modCount;
--size;
afterNodeRemoval(node); //⭐️⭐️⭐️
return node;
}
}
return null;
}
在HashMap的removeNode方法里,当时学习HashMap的时候还是有疑惑的这个方法干啥使的,还是一个没有方法体的空实现方法,现在明白了,就是在给子类重写呢,所以说LinkedHashMap增删改查基本上全是HashMap的逻辑。
(3).改
有几点要注意
1).首先声明一点afterNodeAccess这个方法虽然在HashMap中改变键值对value值的时候都会调用,但是它和改变值没啥关系,真正的改值的逻辑是HashMap中的例如putVal方法,这个方法只是在改完值之后调用一下
final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
boolean evict) {
...
if (e != null) { // existing mapping for key
V oldValue = e.value;
if (!onlyIfAbsent || oldValue == null)
e.value = value;
afterNodeAccess(e); //⭐️⭐️⭐️⭐️
return oldValue;
}
}
++modCount;
if (++size > threshold)
resize();
afterNodeInsertion(evict);
return null;
}
2).afterNodeAccess的真正作用是把刚刚访问过的节点放到双向链的末尾,一旦执行这个方法那就会打乱我们由插入顺序形成的链表,这个逻辑执不执行由accessOrder变量控制
/**
* 此方法的作用是将刚刚访问的节点e放到链表的尾端
*/
void afterNodeAccess(Node<K,V> e) {
LinkedHashMap.Entry<K,V> last;
// accessOrder = true 时 访问节点后才需要置于尾端
// 如果e本身就在尾端,那就不需要操作
if (accessOrder && (last = tail) != e) {
// 记录节点e、e的前驱、e的后继
LinkedHashMap.Entry<K,V> p = (LinkedHashMap.Entry<K,V>)e, b = p.before, a = p.after;
// 第一步:现将p.after置空
p.after = null;
// 第二步:将e的前驱.after 连接上e的后继
if (b == null)
// b记录e的前驱,前驱为null,则e在表头,head置为e的后继
head = a;
else
// 否则 e的前驱.after = e的后继
b.after = a;
// 第三步:将e的后继.before 连接上e的前驱
if (a != null)
// e的后继 != null,将e后继.before = e的前驱
a.before = b;
else
// 否则e的后继 == null,即在e表尾(这里有点多余,前面已经判断在表尾不操作。。。)
last = b;
// 第四步:将节点e接入到链表的尾端
if (last == null)
// last == null,链表为空,head = p
head = p;
else {
// p.before 指向last(链表尾端),尾端.after = p
p.before = last;
last.after = p;
}
// 第四步:更新链表新尾端tail
tail = p;
// 链表结构性调整,修改次数自增
++modCount;
}
}
注意,到底会不会执行这个方法,是由accessOrder变量控制,而这个变量只有在构造方法中指定才会为ture,其他的构造方法默认都是false不执行这段逻辑:
public LinkedHashMap(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
accessOrder = false;
}
/**
* Constructs an empty insertion-ordered <tt>LinkedHashMap</tt> instance
* with the specified initial capacity and a default load factor (0.75).
*
* @param initialCapacity the initial capacity
* @throws IllegalArgumentException if the initial capacity is negative
*/
public LinkedHashMap(int initialCapacity) {
super(initialCapacity);
accessOrder = false;
}
/**
* Constructs an empty insertion-ordered <tt>LinkedHashMap</tt> instance
* with the default initial capacity (16) and load factor (0.75).
*/
public LinkedHashMap() {
super();
accessOrder = false;
}
/**
* Constructs an insertion-ordered <tt>LinkedHashMap</tt> instance with
* the same mappings as the specified map. The <tt>LinkedHashMap</tt>
* instance is created with a default load factor (0.75) and an initial
* capacity sufficient to hold the mappings in the specified map.
*
* @param m the map whose mappings are to be placed in this map
* @throws NullPointerException if the specified map is null
*/
public LinkedHashMap(Map<? extends K, ? extends V> m) {
super();
accessOrder = false;
putMapEntries(m, false);
}
/**
* Constructs an empty <tt>LinkedHashMap</tt> instance with the
* specified initial capacity, load factor and ordering mode.
*
* @param initialCapacity the initial capacity
* @param loadFactor the load factor
* @param accessOrder the ordering mode - <tt>true</tt> for
* access-order, <tt>false</tt> for insertion-order
* @throws IllegalArgumentException if the initial capacity is negative
* or the load factor is nonpositive
*/
public LinkedHashMap(int initialCapacity,
float loadFactor,
boolean accessOrder) {
super(initialCapacity, loadFactor);
this.accessOrder = accessOrder;
}
(4).查
public V get(Object key) {
Node<K,V> e;
if ((e = getNode(hash(key), key)) == null)
return null;
if (accessOrder)
afterNodeAccess(e);
return e.value;
}
/**
* {@inheritDoc}
*/
public V getOrDefault(Object key, V defaultValue) {
Node<K,V> e;
if ((e = getNode(hash(key), key)) == null)
return defaultValue;
if (accessOrder)
afterNodeAccess(e);
return e.value;
}
没啥好说的,都是调用的HashMap的代码。
3.遍历
遍历 和hashMap一样,只不过重写了一些方法,重写是为了按插入顺序遍历
public Set<K> keySet() {
Set<K> ks = keySet;
if (ks == null) {
ks = new LinkedKeySet();
keySet = ks;
}
return ks;
}
final class LinkedKeySet extends AbstractSet<K> {
public final int size() { return size; }
public final void clear() { LinkedHashMap.this.clear(); }
public final Iterator<K> iterator() {
return new LinkedKeyIterator();
}
public final boolean contains(Object o) { return containsKey(o); }
public final boolean remove(Object key) {
return removeNode(hash(key), key, null, false, true) != null;
}
public final Spliterator<K> spliterator() {
return Spliterators.spliterator(this, Spliterator.SIZED |
Spliterator.ORDERED |
Spliterator.DISTINCT);
}
public final void forEach(Consumer<? super K> action) {
if (action == null)
throw new NullPointerException();
int mc = modCount;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after)
action.accept(e.key);
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
public Collection<V> values() {
Collection<V> vs = values;
if (vs == null) {
vs = new LinkedValues();
values = vs;
}
return vs;
}
final class LinkedValues extends AbstractCollection<V> {
public final int size() { return size; }
public final void clear() { LinkedHashMap.this.clear(); }
public final Iterator<V> iterator() {
return new LinkedValueIterator();
}
public final boolean contains(Object o) { return containsValue(o); }
public final Spliterator<V> spliterator() {
return Spliterators.spliterator(this, Spliterator.SIZED |
Spliterator.ORDERED);
}
public final void forEach(Consumer<? super V> action) {
if (action == null)
throw new NullPointerException();
int mc = modCount;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after)
action.accept(e.value);
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
/**
* Returns a {@link Set} view of the mappings contained in this map.
* The set is backed by the map, so changes to the map are
* reflected in the set, and vice-versa. If the map is modified
* while an iteration over the set is in progress (except through
* the iterator's own <tt>remove</tt> operation, or through the
* <tt>setValue</tt> operation on a map entry returned by the
* iterator) the results of the iteration are undefined. The set
* supports element removal, which removes the corresponding
* mapping from the map, via the <tt>Iterator.remove</tt>,
* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
* <tt>clear</tt> operations. It does not support the
* <tt>add</tt> or <tt>addAll</tt> operations.
* Its {@link Spliterator} typically provides faster sequential
* performance but much poorer parallel performance than that of
* {@code HashMap}.
*
* @return a set view of the mappings contained in this map
*/
public Set<Map.Entry<K,V>> entrySet() {
Set<Map.Entry<K,V>> es;
return (es = entrySet) == null ? (entrySet = new LinkedEntrySet()) : es;
}
final class LinkedEntrySet extends AbstractSet<Map.Entry<K,V>> {
public final int size() { return size; }
public final void clear() { LinkedHashMap.this.clear(); }
public final Iterator<Map.Entry<K,V>> iterator() {
return new LinkedEntryIterator();
}
public final boolean contains(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry<?,?> e = (Map.Entry<?,?>) o;
Object key = e.getKey();
Node<K,V> candidate = getNode(hash(key), key);
return candidate != null && candidate.equals(e);
}
public final boolean remove(Object o) {
if (o instanceof Map.Entry) {
Map.Entry<?,?> e = (Map.Entry<?,?>) o;
Object key = e.getKey();
Object value = e.getValue();
return removeNode(hash(key), key, value, true, true) != null;
}
return false;
}
public final Spliterator<Map.Entry<K,V>> spliterator() {
return Spliterators.spliterator(this, Spliterator.SIZED |
Spliterator.ORDERED |
Spliterator.DISTINCT);
}
public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
if (action == null)
throw new NullPointerException();
int mc = modCount;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after)
action.accept(e);
if (modCount != mc)
throw new ConcurrentModificationException();
}
}
// Map overrides
public void forEach(BiConsumer<? super K, ? super V> action) {
if (action == null)
throw new NullPointerException();
int mc = modCount;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after)
action.accept(e.key, e.value);
if (modCount != mc)
throw new ConcurrentModificationException();
}
public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
if (function == null)
throw new NullPointerException();
int mc = modCount;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after)
e.value = function.apply(e.key, e.value);
if (modCount != mc)
throw new ConcurrentModificationException();
}
简单测试一下,是不是按顺序遍历:
public class LinkedHashMapTestMain {
public static void main(String[] args) {
LinkedHashMap<String,String> linkedHashMap = new LinkedHashMap<>();
for (int i = 0; i < 100; i++) {
linkedHashMap.put(i + "", i + "");
}
//第一种entrySet
Set<Map.Entry<String, String>> entrySet = linkedHashMap.entrySet();
Iterator<Map.Entry<String, String>> iterator = entrySet.iterator();
while (iterator.hasNext()) {
Map.Entry<String, String> entry = iterator.next();
System.out.println("entrySet: " + "key: " + entry.getKey() + "--- value: " + entry.getValue());
}
for (Map.Entry<String, String> entry : entrySet){
System.out.println("entrySet forEach循环: " + "key: " + entry.getKey() + "--- value: " + entry.getValue());
}
//第二种keySet
Set<String> keySet = linkedHashMap.keySet();
Iterator<String> keySetIterator = keySet.iterator();
while (keySetIterator.hasNext()){
String key = keySetIterator.next();
System.out.println("keySet: " + "key: " + key + "--- value: " + linkedHashMap.get(key));
}
for (String key : keySet){
System.out.println("keySet forEach循环: " + "key: " + key + "--- value: " + linkedHashMap.get(key));
}
}
}
执行结果:
entrySet: key: 0--- value: 0
entrySet: key: 1--- value: 1
entrySet: key: 2--- value: 2
entrySet: key: 3--- value: 3
entrySet: key: 4--- value: 4
entrySet: key: 5--- value: 5
entrySet: key: 6--- value: 6
entrySet: key: 7--- value: 7
entrySet: key: 8--- value: 8
entrySet: key: 9--- value: 9
entrySet: key: 10--- value: 10
entrySet: key: 11--- value: 11
entrySet: key: 12--- value: 12
entrySet: key: 13--- value: 13
entrySet: key: 14--- value: 14
entrySet: key: 15--- value: 15
entrySet: key: 16--- value: 16
entrySet: key: 17--- value: 17
entrySet: key: 18--- value: 18
entrySet: key: 19--- value: 19
entrySet: key: 20--- value: 20
entrySet: key: 21--- value: 21
entrySet: key: 22--- value: 22
entrySet: key: 23--- value: 23
entrySet: key: 24--- value: 24
entrySet: key: 25--- value: 25
entrySet: key: 26--- value: 26
entrySet: key: 27--- value: 27
entrySet: key: 28--- value: 28
entrySet: key: 29--- value: 29
entrySet: key: 30--- value: 30
entrySet: key: 31--- value: 31
entrySet: key: 32--- value: 32
entrySet: key: 33--- value: 33
entrySet: key: 34--- value: 34
entrySet: key: 35--- value: 35
entrySet: key: 36--- value: 36
entrySet: key: 37--- value: 37
entrySet: key: 38--- value: 38
entrySet: key: 39--- value: 39
entrySet: key: 40--- value: 40
entrySet: key: 41--- value: 41
entrySet: key: 42--- value: 42
entrySet: key: 43--- value: 43
entrySet: key: 44--- value: 44
entrySet: key: 45--- value: 45
entrySet: key: 46--- value: 46
entrySet: key: 47--- value: 47
entrySet: key: 48--- value: 48
entrySet: key: 49--- value: 49
entrySet: key: 50--- value: 50
entrySet: key: 51--- value: 51
entrySet: key: 52--- value: 52
entrySet: key: 53--- value: 53
entrySet: key: 54--- value: 54
entrySet: key: 55--- value: 55
entrySet: key: 56--- value: 56
entrySet: key: 57--- value: 57
entrySet: key: 58--- value: 58
entrySet: key: 59--- value: 59
entrySet: key: 60--- value: 60
entrySet: key: 61--- value: 61
entrySet: key: 62--- value: 62
entrySet: key: 63--- value: 63
entrySet: key: 64--- value: 64
entrySet: key: 65--- value: 65
entrySet: key: 66--- value: 66
entrySet: key: 67--- value: 67
entrySet: key: 68--- value: 68
entrySet: key: 69--- value: 69
entrySet: key: 70--- value: 70
entrySet: key: 71--- value: 71
entrySet: key: 72--- value: 72
entrySet: key: 73--- value: 73
entrySet: key: 74--- value: 74
entrySet: key: 75--- value: 75
entrySet: key: 76--- value: 76
entrySet: key: 77--- value: 77
entrySet: key: 78--- value: 78
entrySet: key: 79--- value: 79
entrySet: key: 80--- value: 80
entrySet: key: 81--- value: 81
entrySet: key: 82--- value: 82
entrySet: key: 83--- value: 83
entrySet: key: 84--- value: 84
entrySet: key: 85--- value: 85
entrySet: key: 86--- value: 86
entrySet: key: 87--- value: 87
entrySet: key: 88--- value: 88
entrySet: key: 89--- value: 89
entrySet: key: 90--- value: 90
entrySet: key: 91--- value: 91
entrySet: key: 92--- value: 92
entrySet: key: 93--- value: 93
entrySet: key: 94--- value: 94
entrySet: key: 95--- value: 95
entrySet: key: 96--- value: 96
entrySet: key: 97--- value: 97
entrySet: key: 98--- value: 98
entrySet: key: 99--- value: 99
entrySet forEach循环: key: 0--- value: 0
entrySet forEach循环: key: 1--- value: 1
entrySet forEach循环: key: 2--- value: 2
entrySet forEach循环: key: 3--- value: 3
entrySet forEach循环: key: 4--- value: 4
entrySet forEach循环: key: 5--- value: 5
entrySet forEach循环: key: 6--- value: 6
entrySet forEach循环: key: 7--- value: 7
entrySet forEach循环: key: 8--- value: 8
entrySet forEach循环: key: 9--- value: 9
entrySet forEach循环: key: 10--- value: 10
entrySet forEach循环: key: 11--- value: 11
entrySet forEach循环: key: 12--- value: 12
entrySet forEach循环: key: 13--- value: 13
entrySet forEach循环: key: 14--- value: 14
entrySet forEach循环: key: 15--- value: 15
entrySet forEach循环: key: 16--- value: 16
entrySet forEach循环: key: 17--- value: 17
entrySet forEach循环: key: 18--- value: 18
entrySet forEach循环: key: 19--- value: 19
entrySet forEach循环: key: 20--- value: 20
entrySet forEach循环: key: 21--- value: 21
entrySet forEach循环: key: 22--- value: 22
entrySet forEach循环: key: 23--- value: 23
entrySet forEach循环: key: 24--- value: 24
entrySet forEach循环: key: 25--- value: 25
entrySet forEach循环: key: 26--- value: 26
entrySet forEach循环: key: 27--- value: 27
entrySet forEach循环: key: 28--- value: 28
entrySet forEach循环: key: 29--- value: 29
entrySet forEach循环: key: 30--- value: 30
entrySet forEach循环: key: 31--- value: 31
entrySet forEach循环: key: 32--- value: 32
entrySet forEach循环: key: 33--- value: 33
entrySet forEach循环: key: 34--- value: 34
entrySet forEach循环: key: 35--- value: 35
entrySet forEach循环: key: 36--- value: 36
entrySet forEach循环: key: 37--- value: 37
entrySet forEach循环: key: 38--- value: 38
entrySet forEach循环: key: 39--- value: 39
entrySet forEach循环: key: 40--- value: 40
entrySet forEach循环: key: 41--- value: 41
entrySet forEach循环: key: 42--- value: 42
entrySet forEach循环: key: 43--- value: 43
entrySet forEach循环: key: 44--- value: 44
entrySet forEach循环: key: 45--- value: 45
entrySet forEach循环: key: 46--- value: 46
entrySet forEach循环: key: 47--- value: 47
entrySet forEach循环: key: 48--- value: 48
entrySet forEach循环: key: 49--- value: 49
entrySet forEach循环: key: 50--- value: 50
entrySet forEach循环: key: 51--- value: 51
entrySet forEach循环: key: 52--- value: 52
entrySet forEach循环: key: 53--- value: 53
entrySet forEach循环: key: 54--- value: 54
entrySet forEach循环: key: 55--- value: 55
entrySet forEach循环: key: 56--- value: 56
entrySet forEach循环: key: 57--- value: 57
entrySet forEach循环: key: 58--- value: 58
entrySet forEach循环: key: 59--- value: 59
entrySet forEach循环: key: 60--- value: 60
entrySet forEach循环: key: 61--- value: 61
entrySet forEach循环: key: 62--- value: 62
entrySet forEach循环: key: 63--- value: 63
entrySet forEach循环: key: 64--- value: 64
entrySet forEach循环: key: 65--- value: 65
entrySet forEach循环: key: 66--- value: 66
entrySet forEach循环: key: 67--- value: 67
entrySet forEach循环: key: 68--- value: 68
entrySet forEach循环: key: 69--- value: 69
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entrySet forEach循环: key: 73--- value: 73
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keySet forEach循环: key: 25--- value: 25
keySet forEach循环: key: 26--- value: 26
keySet forEach循环: key: 27--- value: 27
keySet forEach循环: key: 28--- value: 28
keySet forEach循环: key: 29--- value: 29
keySet forEach循环: key: 30--- value: 30
keySet forEach循环: key: 31--- value: 31
keySet forEach循环: key: 32--- value: 32
keySet forEach循环: key: 33--- value: 33
keySet forEach循环: key: 34--- value: 34
keySet forEach循环: key: 35--- value: 35
keySet forEach循环: key: 36--- value: 36
keySet forEach循环: key: 37--- value: 37
keySet forEach循环: key: 38--- value: 38
keySet forEach循环: key: 39--- value: 39
keySet forEach循环: key: 40--- value: 40
keySet forEach循环: key: 41--- value: 41
keySet forEach循环: key: 42--- value: 42
keySet forEach循环: key: 43--- value: 43
keySet forEach循环: key: 44--- value: 44
keySet forEach循环: key: 45--- value: 45
keySet forEach循环: key: 46--- value: 46
keySet forEach循环: key: 47--- value: 47
keySet forEach循环: key: 48--- value: 48
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keySet forEach循环: key: 50--- value: 50
keySet forEach循环: key: 51--- value: 51
keySet forEach循环: key: 52--- value: 52
keySet forEach循环: key: 53--- value: 53
keySet forEach循环: key: 54--- value: 54
keySet forEach循环: key: 55--- value: 55
keySet forEach循环: key: 56--- value: 56
keySet forEach循环: key: 57--- value: 57
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keySet forEach循环: key: 60--- value: 60
keySet forEach循环: key: 61--- value: 61
keySet forEach循环: key: 62--- value: 62
keySet forEach循环: key: 63--- value: 63
keySet forEach循环: key: 64--- value: 64
keySet forEach循环: key: 65--- value: 65
keySet forEach循环: key: 66--- value: 66
keySet forEach循环: key: 67--- value: 67
keySet forEach循环: key: 68--- value: 68
keySet forEach循环: key: 69--- value: 69
keySet forEach循环: key: 70--- value: 70
keySet forEach循环: key: 71--- value: 71
keySet forEach循环: key: 72--- value: 72
keySet forEach循环: key: 73--- value: 73
keySet forEach循环: key: 74--- value: 74
keySet forEach循环: key: 75--- value: 75
keySet forEach循环: key: 76--- value: 76
keySet forEach循环: key: 77--- value: 77
keySet forEach循环: key: 78--- value: 78
keySet forEach循环: key: 79--- value: 79
keySet forEach循环: key: 80--- value: 80
keySet forEach循环: key: 81--- value: 81
keySet forEach循环: key: 82--- value: 82
keySet forEach循环: key: 83--- value: 83
keySet forEach循环: key: 84--- value: 84
keySet forEach循环: key: 85--- value: 85
keySet forEach循环: key: 86--- value: 86
keySet forEach循环: key: 87--- value: 87
keySet forEach循环: key: 88--- value: 88
keySet forEach循环: key: 89--- value: 89
keySet forEach循环: key: 90--- value: 90
keySet forEach循环: key: 91--- value: 91
keySet forEach循环: key: 92--- value: 92
keySet forEach循环: key: 93--- value: 93
keySet forEach循环: key: 94--- value: 94
keySet forEach循环: key: 95--- value: 95
keySet forEach循环: key: 96--- value: 96
keySet forEach循环: key: 97--- value: 97
keySet forEach循环: key: 98--- value: 98
keySet forEach循环: key: 99--- value: 99
来源:https://blog.csdn.net/m0_37707561/article/details/125336796
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