设值为maxValue。

Set keySet = map.keySet();

keySet.stream().filter(x->map.get(x)==maxValue).forEach(x-> System.out.println(x));

你可以使用下面的:

public class HashmapKeyExist {
    public static void main(String[] args) {
        HashMap<String, String> hmap = new HashMap<String, String>();
        hmap.put("1", "Bala");
        hmap.put("2", "Test");

        Boolean cantain = hmap.containsValue("Bala");
        if(hmap.containsKey("2") && hmap.containsValue("Test"))
        {
            System.out.println("Yes");
        }
        if(cantain == true)
        {
            System.out.println("Yes"); 
        }

        Set setkeys = hmap.keySet();
        Iterator it = setkeys.iterator();

        while(it.hasNext())
        {
            String key = (String) it.next();
            if (hmap.get(key).equals("Bala"))
            {
                System.out.println(key);
            }
        }
    }
}

使用薄包装:HMap

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

public class HMap<K, V> {

   private final Map<K, Map<K, V>> map;

   public HMap() {
      map = new HashMap<K, Map<K, V>>();
   }

   public HMap(final int initialCapacity) {
      map = new HashMap<K, Map<K, V>>(initialCapacity);
   }

   public boolean containsKey(final Object key) {
      return map.containsKey(key);
   }

   public V get(final Object key) {
      final Map<K, V> entry = map.get(key);
      if (entry != null)
         return entry.values().iterator().next();
      return null;
   }

   public K getKey(final Object key) {
      final Map<K, V> entry = map.get(key);
      if (entry != null)
         return entry.keySet().iterator().next();
      return null;
   }

   public V put(final K key, final V value) {
      final Map<K, V> entry = map
            .put(key, Collections.singletonMap(key, value));
      if (entry != null)
         return entry.values().iterator().next();
      return null;
   }
}

从Map中获取给定值的键的最简单实用方法:

public static void fetchValue(Map<String, Integer> map, Integer i)
{   
Stream stream = map.entrySet().stream().filter(val-> val.getValue().equals(i)).map(Map.Entry::getKey);
stream.forEach(System.out::println);    
}

详细解释:

方法fetchValue接受映射，该映射的键是String，值是Integer。 然后使用entryset().stream()将结果转换为流。 接下来，我们使用过滤器(中间操作)，它会给我们一个等于第二个参数的值。 最后，我们使用forEach(最终操作)来打印最终结果。

public static class SmartHashMap <T1 extends Object, T2 extends Object> {
    public HashMap<T1, T2> keyValue;
    public HashMap<T2, T1> valueKey;

    public SmartHashMap(){
        this.keyValue = new HashMap<T1, T2>();
        this.valueKey = new HashMap<T2, T1>();
    }

    public void add(T1 key, T2 value){
        this.keyValue.put(key, value);
        this.valueKey.put(value, key);
    }

    public T2 getValue(T1 key){
        return this.keyValue.get(key);
    }

    public T1 getKey(T2 value){
        return this.valueKey.get(value);
    }

}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

public class M{
public static void main(String[] args) {

        HashMap<String, List<String>> resultHashMap = new HashMap<String, List<String>>();

        Set<String> newKeyList = resultHashMap.keySet();


        for (Iterator<String> iterator = originalHashMap.keySet().iterator(); iterator.hasNext();) {
            String hashKey = (String) iterator.next();

            if (!newKeyList.contains(originalHashMap.get(hashKey))) {
                List<String> loArrayList = new ArrayList<String>();
                loArrayList.add(hashKey);
                resultHashMap.put(originalHashMap.get(hashKey), loArrayList);
            } else {
                List<String> loArrayList = resultHashMap.get(originalHashMap
                        .get(hashKey));
                loArrayList.add(hashKey);
                resultHashMap.put(originalHashMap.get(hashKey), loArrayList);
            }
        }

        System.out.println("Original HashMap : " + originalHashMap);
        System.out.println("Result HashMap : " + resultHashMap);
    }
}