转载自:https://blog.csdn.net/qq_28051453/article/details/52622068
public V put(K key, V value) { return putVal(hash(key), key, value, false, true); } final V putVal(int hash, K key, V value, boolean onlyIfAbsent, boolean evict) { Node<K,V>[] tab; Node<K,V> p; int n, i; //如果table数组为空或者长度为0,则进行扩容 if ((tab = table) == null || (n = tab.length) == 0) n = (tab = resize()).length; //根据hash算法算出存储的下标,如果为空,即不发生碰撞,则直接存储 if ((p = tab[i = (n - 1) & hash]) == null) tab[i] = newNode(hash, key, value, null); else { Node<K,V> e; K k; //如果发生碰撞,且键值对已经存在,则进行值得覆盖 if (p.hash == hash && ((k = p.key) == key || (key != null && key.equals(k)))) e = p; //存储为树 else if (p instanceof TreeNode) e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value); else { //链表 for (int binCount = 0; ; ++binCount) { if ((e = p.next) == null) { p.next = newNode(hash, key, value, null); //如果链上的结点大于</span><span style="font-size:14px;">REEEIFY_THRESHOLD(默认为8),则转化为红黑树 if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st treeifyBin(tab, hash); break; } if (e.hash == hash && ((k = e.key) == key || (key != null && key.equals(k)))) break; p = e; } } 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; } ———————————————— 版权声明:本文为CSDN博主「南瓜灯cc」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。 原文链接:https://blog.csdn.net/qq_28051453/article/details/52622068