1 package cn.itcast.p4.generic.definedemo;
 2 
 3 import cn.itcast.p2.bean.Student;
 4 import cn.itcast.p2.bean.Worker;
 5 
 6 public class GenericDefineDemo3 {
 7 
 8     public static void main(String[] args) {
 9         // TODO Auto-generated method stub
10         Tool<Student> tool = new Tool<Student>();
 
11         
12         tool.setObject(new Student());
13 //        tool.setObject(new Worker());//編譯時就發現型別不同
14         Student stu = (Student)tool.getObject();
15 //        Tool tool = new Tool();        
16 //        tool.setObject(new Worker());        
17 //        Student stu = (Student)tool.getObject();
 

18     }
19 
20 }

 1 package cn.itcast.p4.generic.definedemo;
 2 
 3 import cn.itcast.p2.bean.Object;
 4 //定義一個工具類操作所有物件
 5 /*
 6  * public class Tool { private Object object;
 7  * 
 8  * public Object getObject() { return object; }
 9  * 
10  * public void setObject(Object object) { this.object = object; }
 
11  * 
12  * }
13  */
14 //在jdk1.5後，使用泛型來接收類中要操作的引用資料型別。
15 //泛型類。什麼時候用？當類中的操作的引用資料型別不確定的時候，就使用泛型來表示。
16 public class Tool<QQ>{
17     private QQ q;
18 
19     public QQ getObject() {
20         return q;
21     }
22 
23     public void setObject(QQ object) {
24         this.q = object;
25     }
26     
27 }

 1 package cn.itcast.p2.bean;
 2 
 3 import java.util.Comparator;
 4 
 5 public class Person implements Comparable<Person>{
 6     private String name;
 7     private int age;
 8     
 9     
10     public Person() {
11         super();
12         // TODO Auto-generated constructor stub
13     }
14     
15     public Person(String name, int age) {
16         super();
17         this.name = name;
18         this.age = age;
19     }
20     public int compareTo(Person p) {//指定比較型別，傳入比較型別
21 //        Person p= (Person)obj;
22         int temp = this.age-p.age;
23         return temp==0?this.name.compareTo(p.name):temp;
24     }
25     
26     
27 //    @Override
28 //    public boolean equals(Object obj) {//不能把Object改為Person，equals方法來自Object，Object沒有定義泛型
29 //        // TODO Auto-generated method stub
30 //        if (this == obj) {
31 //            return true;
32 //        }
33 //        if (!(obj instanceof Person)) {
34 //            throw new RuntimeException()
35 //        }
36 //        Person p = (Person)obj;
37 //        return super.equals(obj);
38 //    }
39     /*
40      * @Override public int hashCode() { final int prime = 31; int result = 1;
41      * result = prime * result + age; result = prime * result + ((name == null) ? 0
42      * : name.hashCode()); return result; }
43      * 
44      * @Override public boolean equals(Object obj) { if (this == obj) return true;
45      * if (obj == null) return false; if (getClass() != obj.getClass()) return
46      * false; Person other = (Person) obj; if (age != other.age) return false; if
47      * (name == null) { if (other.name != null) return false; } else if
48      * (!name.equals(other.name)) return false; return true; }//alt+shift+s
49      * hashCode和equals
50      */
51     public String getName() {
52         return name;
53     }
54     public void setName(String name) {
55         this.name = name;
56     }
57     public int getAge() {
58         return age;
59     }
60     public void setAge(int age) {
61         this.age = age;
62     }
63     
64 }

 1 package cn.itcast.p2.bean;
 2 
 3 public class Student extends Person {
 4 
 5     public Student() {
 6         super();
 7         // TODO Auto-generated constructor stub
 8     }
 9 
10     public Student(String name, int age) {
11         super(name, age);
12         // TODO Auto-generated constructor stub
13     }
14     
15 }

 1 package cn.itcast.p2.bean;
 2 
 3 public class Worker extends Person {
 4 
 5     public Worker() {
 6         super();
 7         // TODO Auto-generated constructor stub
 8     }
 9 
10     public Worker(String name, int age) {
11         super(name, age);
12         // TODO Auto-generated constructor stub
13     }
14     
15 }