8-3 泛型

package generic;

public class GenericOne {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        GenericOne.<String>getMiddle("a","b","c");
    }
    
    /**
     * 泛型可以被不同类型的对象重用
     * 
     * 构造函数可以省略泛型类型
     */
    
    //定义简单泛型类
    class Pair<T>{
        private T first;
        private T second;
        
        public Pair(){}

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

        public T getFirst() {
            return first;
        }

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

        public T getSecond() {
            return second;
        }

        public void setSecond(T second) {
            this.second = second;
        };
    }
    
    //泛型方法，可以定义在泛型或非泛型方法中
    //在方法名的方扩号内定义具体的类
    public static <T>T getMiddle(T ... a){
        return a[a.length/2];
    }

}