Question

我正在尝试编写一个接受InputStream变量的方法，并将HashMap返回给main。但是我仍然坚持如何返回HashMap的变量。 Java新手，所以我不知道我做错了什么。对于return语句：pairCount无法解析为变量。提前谢谢。

private static Map<String, Integer> getHashMap(InputStream in)
{ 

    if (in != null) 
    {
        // Using a Scanner object to read one word at a time from the input stream.
        @SuppressWarnings("resource")
        Scanner sc = new Scanner(in);   
        String word;
        System.out.println(" - Assignment 1 -s%n%n\n");
        // Continue getting words until we reach the end of input 
        List<String> inputWords = new ArrayList<String>();

        while (sc.hasNext()) 
        {  
            word = sc.next();       
            if (!word.equals(null)) 
            {
                inputWords.add(word);
            }
        }
        Map<String, Integer> pairsCount = new HashMap<>();
        Iterator<String> it = inputWords.iterator();

        String currentWord = null;
        String previousWord = null;

        Integer wordCount = 0;
        while(it.hasNext())
        {
            currentWord = it.next();
            if( previousWord != null ) 
            {
                String key = previousWord.concat( "#" ).concat( currentWord );
            if( pairsCount.containsKey( key ) ) 
            {
              Integer lastCount = pairsCount.get( key );
              pairsCount.put( key, lastCount + 1 );
              wordCount = wordCount + lastCount;
            } 
            else 
            {
              pairsCount.put( key, 1 );
              wordCount =  1;
            }
         }
            previousWord = currentWord;     

     }

    }
    return (pairsCount);

}

Answer 1

这可能是因为变量pairsCount超出了它的范围。

您可以在if块中定义它，但尝试将其返回到外部。

所以尝试定义Map pairsCount = new HashMap＆lt;＆gt;（）; 在if之前（in！= null）

从文本返回hashmap的方法

1 个答案: