Javamap根据value获取所有key

Posted 2022-08-07 Ctrl练习生-谢哥哥blog

代码如下：

    /**
     * 根据value获取所有key
     */
    private static Set<String> getKeys(Map<String,String> map, String value)
        Set<String> keySet = new HashSet<>();
        // 遍历map
        for (Map.Entry<String, String> entry : map.entrySet()) 
            // 如果value和key对应的value相同
            if(value.equals(entry.getValue()))
                keySet.add(entry.getKey());
            
        
        return keySet;
    

    public static void main(String[] args) 
        Map<String,String> map = new HashMap<>();
        map.put("key1", "value1");
        map.put("key2", "value2");
        map.put("key3", "value1");
        map.put("key4", "value2");
        map.put("key5", "value2");
        map.put("key6", "value3");
        // 获取所有value2的key值
        Set<String> keySet = getKeys(map, "value2");
        for (String key : keySet) 
            System.out.println(key);
        
    

测试运行