需要添加代碼才能返回空數組爲空

Question

如果數組列表爲空，此代碼將返回錯誤。我需要添加代碼以避免錯誤，如果爲空則返回null。由於

public Comment findMostHelpfulComment() 
{ 
    Iterator<Comment> it = comments.iterator(); 
    Comment best = it.next(); 
    while(it.hasNext()) 
    { 
     Comment current = it.next(); 
     if(current.getVoteCount() > best.getVoteCount()) { 
      best = current; 
     } 
    } 

return best; 
} 

Answer 1

public Comment findMostHelpfulComment() 
{ 
    if (comments.isEmpty()) { 
     return null; 
    } 

    // rest of method 
} 

或者，如果你返工的循環一點，你可以用null最好的註解開始。

public Comment findMostHelpfulComment() 
{ 
    Comment best = null; 

    for (Comment current: comments) { 
     if (best == null || current.getVoteCount() > best.getVoteCount()) { 
      best = current; 
     } 
    } 

    return best; 
} 

Answer 2

public Comment findMostHelpfulComment() 
{ 
    Iterator<Comment> it = comments.iterator(); 
    Comment best = new Comment(); 
    best.setVoteCount(0); 
    while(it.hasNext()) 
    { 
     Comment current = it.next(); 
     if(current.getVoteCount() > best.getVoteCount()) { 
      best = current; 
     } 
    } 
    return best; 
} 

試試這個。它不會有空陣列的問題，但它會返回一個虛擬的Comment，其中voteCount設置爲0;