Java面向对象程序设计--泛型编程

1. 为何要进行泛型编程？

泛型变成为不同类型集合提供相同的代码！省去了为不同类型而设计不同代码的麻烦！

2. 一个简单泛型类的定义:

 1 public class PairTest1

 2 {

 3     public static void main(String[] args)

 4     {

 5         String[] arr = {"This","is","the","end","of","the","world"};

 6         Pair<String> mm = ArrayAlg.minmax(arr);

 7         System.out.println("min = " + mm.getFirst());

 8         System.out.println("max = " + mm.getSecond());

 9     }

10 }

11

12 class Pair<T>

13 {

14     public Pair() {first = null; second = null;}

15     public Pair(T first,T second) {this.first = first; this.second = second;}

16

17     public T getFirst() {return first;}

18     public T getSecond() {return second;}

19

20     public void setFirst(T newValue) {this.first = newValue;}

21     public void setSecond(T newValue) {this.second = newValue;}

22

23     private T first;

24     private T second;

25 }

26

27 class ArrayAlg

28 {

29     public static Pair<String> minmax(String[] a)

30     {

31         if(a == null || a.length == 0) return null;

32         String min = a[0];

33         String max = a[0];

34         for(int i = 1; i < a.length; i++)

35         {

36             if(min.compareTo(a[i]) > 0) min = a[i];

37             if(max.compareTo(a[i]) < 0) max = a[i];

38         }

39         return new Pair<String>(min,max);

40     }

41 }

上面这段代码中定义了一个泛型类。

2. 泛型函数：

Java面向对象程序设计--泛型编程