029_自己实现一个HashMap

import java.util.AbstractCollection; import java.util.AbstractSet; import java.util.Collection; import java.util.Iterator; import java.util.Set;/*** 简易HashMap* 数组 + 单向链表*/ public class MyHashMap {private Node[] table;private int size;private int initCapacity = 16;public MyHashMap() {table = new Node[initCapacity];}/*** hash表存放键值对个数* @return*/public int size() {return size;}/*** hash表是否为空* @return*/public boolean isEmpty() {return size == 0;}/*** 存放键值对* @param key* @param value* @return*/public boolean put(Object key, Object value) {int hash = Math.abs(key.hashCode()) % initCapacity;Node x = table[hash];if(x == null) {table[hash] = new Node(key, value, null);size++;return true;}else {Node n;for(n = x; n != null; n = n.next) {if(key.equals(n.key)) {n.value = value;return true;}x = n;}x.next = new Node(key, value, null);size++;return true;}}/*** 根据健获取值* @param key* @return*/public Object get(Object key) {int hash = Math.abs(key.hashCode()) % initCapacity;for(Node n = table[hash]; n != null; n = n.next) {if(key.equals(n.key)) {return n.value;}}return null;}/*** Hash迭代类*/class MyHashIterator{Node next;int index;public MyHashIterator() {index = 0;next = null;if(table != null && size > 0) {do {}while(index < table.length && (next = table[index++]) == null);}}public final boolean hasNext() {return next != null;}public final Node nextNode() {Node e = next;if((next = e.next) == null) {do {}while(index < table.length && (next = table[index++]) == null); }return e;}}/*** 返回键的Set集合* @return*/public Set<Object> MykeySet() {return new MyKeySet();}/*** 键的Set类*/final class MyKeySet extends AbstractSet<Object>{public Iterator<Object> iterator() {return new MyKeyIterator();}public int size() {return size;}}/*** 键的迭代类*/final class MyKeyIterator extends MyHashIterator implements Iterator<Object>{public Object next() {return nextNode().key;}}/*** 值的集合* @return*/public Collection<Object> values() {return new MyValues();}/*** 值的集合类*/final class MyValues extends AbstractCollection<Object>{public Iterator<Object> iterator() {return new MyValueIterator();}public int size() {return size;}}/*** 值的迭代类*/final class MyValueIterator extends MyHashIterator implements Iterator<Object>{public Object next() {return nextNode().value;}} }/*** 节点类*/ class Node{Object key;Object value;Node next;public Node(Object key, Object value, Node next) {this.key = key;this.value = value;this.next = next;} }

 

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