HashMap底层实现练习

/**
 * Created by chengbx on 2018/5/19.
 * 简单版
 */
public class CbxMap {
    CbxEntry [] cbxEntries = new CbxEntry[999];
    int size;
    public void put(Object key,Object value){
        //解决键重复的问题
        for (int i = 0; i < size; i++) {
            if(cbxEntries[i].getKey().equals(key)){
                cbxEntries[i].setValue(value);
                return ;
            }
        }
        CbxEntry cbxEntry = new CbxEntry(key,value);
        cbxEntries[size++] = cbxEntry;
    }
    public Object get(Object key){
        for (int i = 0; i < size; i++) {
            if(cbxEntries[i].getKey().equals(key)){
                return cbxEntries[i].getValue();
            }
        }
        return null;
    }
    public boolean containsKey(Object key){
        for (int i = 0; i < size; i++) {
            if(cbxEntries[i].getKey().equals(key)){
                return true;
            }
        }
        return  false;
    }
    public boolean containsValue(Object value){
        for (int i = 0; i < size; i++) {
            if(cbxEntries[i].getValue().equals(value)){
                return true;
            }
        }
        return  false;
    }

}
class CbxEntry{
    private Object key;
    private Object value;

    public Object getKey() {
        return key;
    }

    public void setKey(Object key) {
        this.key = key;
    }

    public Object getValue() {
        return value;
    }

    public void setValue(Object value) {
        this.value = value;
    }

    public CbxEntry(Object key, Object value) {
        this.key = key;
        this.value = value;
    }
}

/**
 * Created by chengbx on 2018/5/19.
 * 优化版
 */
public class CbxHashMap {
    LinkedList[] linkedArr = new LinkedList[999];//Map的底层结构就是：数组 + 链表
    int size;
    public  int getHashCodeByKey(Object key){
        return key.hashCode() % linkedArr.length;
    }

    public void put(Object key,Object value){
       CbxEntry cbxEntry = new CbxEntry(key,value);
       int arrIndex = getHashCodeByKey(key);
       if(linkedArr[arrIndex]==null){
            LinkedList linkedList = new LinkedList();
            linkedList.add(cbxEntry);
            linkedArr[arrIndex] = linkedList;
       }else{
           linkedArr[arrIndex].add(cbxEntry);
       }
    }

    public Object get(Object key){
        int arrIndex = getHashCodeByKey(key);
        if(linkedArr[arrIndex]!=null){
            LinkedList linkedList= linkedArr[arrIndex];
            for (int i = 0; i <linkedList.size() ; i++) {
                CbxEntry cbxEntry = (CbxEntry)linkedList.get(i);
                if(cbxEntry.getKey().equals(key)){
                    return cbxEntry.getValue();
                }
            }
        }
        return null;
    }

}