java高薪之路__004_泛型

 1 package learn.JavaBasics.Class;
 2 
 3 public class GenericDemo {
 4     private class Test<E> {
 5         private E i;
 6         
 7         public E get() {
 8             return this.i;
 9         }
10         
11         public void set(E str) {
12             this.i = str;
13         }
14         
15         public void echo() {
16             System.out.println("echo test");
17         }
18     }
19     
20     public interface testInterface<E> {
21         public E print();
22     }
23     
24     /**
25      * @param args
26      */
27     public static void main(String[] args) {
28         // TODO Auto-generated method stub
29         GenericDemo g = new GenericDemo();
30         
31         Test<Integer> a = g.new Test<Integer>();
32         a.set(112);
33         System.out.println(a.get());
34         
35         Test<String> s = g.new Test<String>();
36         s.set("hello");
37         System.out.println(s.get());
38                 
39         g.put(a);
40         g.put(s);
41         
42 //        g.putExtends(a);
43         g.putExtends(s);
44         
45         g.putSuper(a);
46 //        g.putSuper(s);
47         
48         System.out.println("*****");
49         
50         g.question(a).echo();
51         g.question(s).echo();
52         
53         String is = new testInterface<String>() {
54             @Override
55             public String print() {
56                 // TODO Auto-generated method stub
57                 
58                 return "Interface Generic Test";
59             }            
60         }.print();
61         
62         System.out.println(is);
63     }
64     
65     public void put(Test<?> t) {
66         System.out.println(t.get());
67     }
68 
69     public void putExtends(Test<? extends String> t) {
70         System.out.println(t.get());
71     }
72     
73     public void putSuper(Test<? super Integer> t) {
74         System.out.println(t.get());
75     }
76     
77     public Test<?> question(Test<?> t) {
78         System.out.println(t);
79         return t;
80     }
81 }