Java:Java面试问题的澄清

Question

我最近参加了Java面试问题并得到了以下查询,我不知道答案

1>我有下课

 class CricketTeam{             
   String name; //this is the complete name(inclusive of first and last name)          
 }             

板球运动员的名字如下:

1> Sachin Tendulkar
2> Gautam Gambhir
3> Ricky Ponting
4> Shahid Afridi
5> Kevin Pieterson
6> MS Dhoni

我想通过他们的last name only.Suugestions /代码对上面的Cricket Players名称进行排序.我们将不胜感激.

2> 在java 中使用enhanced for loop反对 iterator有什么好处.在java中使用增强的for循环的优点是什么？为什么它可以在java工作时首先在java中引入iterator.

Answer 1

1. 实现一个Comparator从玩家名称中解析姓氏并对其进行比较,然后使用该比较器对板球运动员的集合进行排序.
   一个简单的例子(没有错误处理,假设所有玩家只有一个名字而没有中间名):

   class CricketTeamComparator implements Comparator<CricketTeam> {
       @Override
       public int compare(CricketTeam o1, CricketTeam o2) {
           String lastName1 = o1.name.split(" ")[1];
           String lastName2 = o2.name.split(" ")[1];
           return lastName1.compareTo(lastName2);
       }
   }
   
   ...
   
   List<CricketTeam> team = new ArrayList<CricketTeam>();
   ...
   Collections.sort(team, new CricketTeamComparator());
   

2. 它更干净,更简洁,更安全(例如,当迭代器通过调用next()太多次而意外增加时,避免了多个嵌入循环中的特定细微错误).
   代码示例(来自Effective Java 2nd Edition,Item 46:Prefer for-each loops to traditional for loops):

   // Can you spot the bug?
   enum Suit { CLUB, DIAMOND, HEART, SPADE }
   enum Rank { ACE, DEUCE, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT,
   NINE, TEN, JACK, QUEEN, KING }
   ...
   Collection<Suit> suits = Arrays.asList(Suit.values());
   Collection<Rank> ranks = Arrays.asList(Rank.values());
   List<Card> deck = new ArrayList<Card>();
   for (Iterator<Suit> i = suits.iterator(); i.hasNext(); )
     for (Iterator<Rank> j = ranks.iterator(); j.hasNext(); )
       deck.add(new Card(i.next(), j.next()));