import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; public class MapValueGetKey { public static void main(String[] args) { Map map = new HashMap<>(); map.put(1,"A"); map.put(2,"A"); map.put(3,"A"); map.put(4,"A"); map.put(5,"A"); String value = "A"; ArrayList arr = valueGetKey(map, value); if(!arr.isEmpty()) { for(int i=0; i<arr.size(); i++) { System.out.println(arr.get(i)); } } } private static ArrayList valueGetKey(Map map,String value) { Set set = map.entrySet(); ArrayList arr = new ArrayList<>(); Iterator it = set.iterator(); while(it.hasNext()) { Map.Entry entry = (Map.Entry)it.next(); if(entry.getValue().equals(value)) { int s = (int)entry.getKey(); arr.add(s); } } return arr; } }
结果如下:
1 2 3 4 5
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