你没用过这个集合吧？IdentityHashMap

public class IdentityHashMap<K,V>    extends AbstractMap<K,V>    implements Map<K,V>, java.io.Serializable, Cloneable{...}

1. public IdentityHashMap() {        init(DEFAULT_CAPACITY);    }2. public IdentityHashMap(int expectedMaxSize) {        if (expectedMaxSize < 0)            throw new IllegalArgumentException("expectedMaxSize is negative: "                                               + expectedMaxSize);        init(capacity(expectedMaxSize));    }3.  public IdentityHashMap(Map<? extends K, ? extends V> m) {        // Allow for a bit of growth        this((int) ((1 + m.size()) * 1.1));        putAll(m);    }      

  /**       * The initial capacity used by the no-args constructor.     * MUST be a power of two.  The value 32 corresponds to the     * (specified) expected maximum size of 21, given a load factor     * of 2/3.     */    哎嗨？初始容量大小32    private static final int DEFAULT_CAPACITY = 32;
    /**     * The minimum capacity, used if a lower value is implicitly specified     * by either of the constructors with arguments.  The value 4 corresponds     * to an expected maximum size of 2, given a load factor of 2/3.     * MUST be a power of two.     */    private static final int MINIMUM_CAPACITY = 4;
    /**     * The maximum capacity, used if a higher value is implicitly specified     * by either of the constructors with arguments.     * MUST be a power of two <= 1<<29.     *     * In fact, the map can hold no more than MAXIMUM_CAPACITY-1 items     * because it has to have at least one slot with the key == null     * in order to avoid infinite loops in get(), put(), remove()     */   最大容量1<<29    private static final int MAXIMUM_CAPACITY = 1 << 29;    Hashmap//最大的容量上限为 2^30    static final int MAXIMUM_CAPACITY = 1 << 30;    /**     * The table, resized as necessary. Length MUST always be a power of two.     */    transient Object[] table; // non-private to simplify nested class access
    /**     * The number of key-value mappings contained in this identity hash map.     *     * @serial     */    int size;

 public V put(K key, V value) {        final Object k = maskNull(key);        retryAfterResize: for (;;) {            final Object[] tab = table;            final int len = tab.length;            int i = hash(k, len);
            for (Object item; (item = tab[i]) != null;                 i = nextKeyIndex(i, len)) {                if (item == k) {                    @SuppressWarnings("unchecked")                        V oldValue = (V) tab[i + 1];                    tab[i + 1] = value;                    return oldValue;                }            }
            final int s = size + 1;            // Use optimized form of 3 * s.            // Next capacity is len, 2 * current capacity.            if (s + (s << 1) > len && resize(len))                continue retryAfterResize;            modCount++;            tab[i] = k;            tab[i + 1] = value;            size = s;            return null;        }    }

        IdentityHashMap<String, String> subnetequipmentMap = new IdentityHashMap<>();               IdentityHashMap<String, String> subnetSrouterMap = new IdentityHashMap<>();               IdentityHashMap<String, String> subnetserverMap = new IdentityHashMap<>();            IdentityHashMap<String, String> routerFirewallMap = new IdentityHashMap<>();            IdentityHashMap<String, String> routerWsubnetMap = new IdentityHashMap<>();
        IdentityHashMap<String, String> dyrouterSubnetMap = new IdentityHashMap<>();        for (Object o : mxCelArr) {            JSONObject object = JSON.parseObject(o.toString());            //校验拓扑连线，对象的属性判断            String edge = object.getString("edge");            //线的数组            //线edge            if (edge != null) {                //断头线                String source = object.getString("source");                String target = object.getString("target");                if (source == null || target == null) {                    //回环线                } else if (source != null && target != null) {                    if (!source.equals(target)) {                                        if (subnetIdList.contains(source) && serverIdList.contains(target) || subnetIdList.contains(target) && serverIdList.contains(source)) {                            subnetserverMap.put(source, target);                        }                                               if (srouterIdList.contains(source) && firewallIdList.contains(target) || srouterIdList.contains(target) && firewallIdList.contains(source)) {                            routerFirewallMap.put(source, target);                        }                        if (subnetIdList.contains(source) && srouterIdList.contains(target) || subnetIdList.contains(target) && srouterIdList.contains(source)) {                            subnetSrouterMap.put(source, target);                        }                        if (srouterIdList.contains(source) && wsubnetIdList.contains(target) || srouterIdList.contains(target) && wsubnetIdList.contains(source)) {                            routerWsubnetMap.put(source, target);                        }                        if (equipmentIdList.contains(source) && subnetIdList.contains(target) || equipmentIdList.contains(target) && subnetIdList.contains(source)) {                            subnetequipmentMap.put(source, target);                        }                        if (routerIdList.contains(source) && subnetIdList.contains(target) || routerIdList.contains(target) && subnetIdList.contains(source)) {                            dyrouterSubnetMap.put(source, target);                        }
                    }                }            }        }        map.put("subnetequipmentMap", subnetequipmentMap);        map.put("subnetSrouterMap", subnetSrouterMap);        map.put("subnetserverMap", subnetserverMap);        map.put("routerFirewallMap", routerFirewallMap);        map.put("routerWsubnetMap", routerWsubnetMap);        map.put("dyrouterSubnetMap", dyrouterSubnetMap);        return map;    }