集合框架-Map集合-TreeMap存储自定义对象

 1 package cn.itcast.p8.treemap.demo;
 2
 3
 4 import java.util.Iterator;
 5 import java.util.Map;
 6 import java.util.TreeMap;
 7
 8 import cn.itcast.p2.bean.Student;
 9 import cn.itcast.p3.comparator.ComparatorByName;
10
11 public class TreeMapDemo {
12
13     public static void main(String[] args) {
14         // TODO Auto-generated method stub
15         TreeMap<Student,String> tm = new TreeMap<Student,String>(new ComparatorByName());
16         tm.put(new Student("lisi",38), "北京");
17         tm.put(new Student("zhaoliu",24), "上海");
18         tm.put(new Student("xiaoqiang",31), "沈阳");
19         tm.put(new Student("wangcai",28), "大连");
20         tm.put(new Student("zhaoliu",24), "铁岭");
21
22         Iterator<Map.Entry<Student, String>> it = tm.entrySet().iterator();
23
24
25         while (it.hasNext()) {
26             Map.Entry<Student, String> me = it.next();
27             Student key = me.getKey();
28             String value = me.getValue();
29             System.out.println(key.getName()+":"+key.getAge()+"---"+value);
30         }
31     }
32
33 }

TreeMapDemo

 1 package cn.itcast.p2.bean;
 2
 3 public class Person implements Comparable<Person>{
 4     private String name;
 5     private int age;
 6
 7
 8     public Person() {
 9         super();
10         // TODO Auto-generated constructor stub
11     }
12
13     public Person(String name, int age) {
14         super();
15         this.name = name;
16         this.age = age;
17     }
18     public int compareTo(Person p) {//指定比较类型，传入比较类型
19 //        Person p= (Person)obj;
20         int temp = this.age-p.age;
21         return temp==0?this.name.compareTo(p.name):temp;
22     }
23
24
25 @Override
26     public int hashCode() {
27         final int prime = 31;
28         int result = 1;
29         result = prime * result + age;
30         result = prime * result + ((name == null) ? 0 : name.hashCode());
31         return result;
32     }
33
34     @Override
35     public boolean equals(Object obj) {
36         if (this == obj)
37             return true;
38         if (obj == null)
39             return false;
40         if (getClass() != obj.getClass())
41             return false;
42         Person other = (Person) obj;
43         if (age != other.age)
44             return false;
45         if (name == null) {
46             if (other.name != null)
47                 return false;
48         } else if (!name.equals(other.name))
49             return false;
50         return true;
51     }
52
53     //    @Override
54 //    public boolean equals(Object obj) {//不能把Object改为Person，equals方法来自Object，Object没有定义泛型
55 //        // TODO Auto-generated method stub
56 //        if (this == obj) {
57 //            return true;
58 //        }
59 //        if (!(obj instanceof Person)) {
60 //            throw new RuntimeException()
61 //        }
62 //        Person p = (Person)obj;
63 //        return super.equals(obj);
64 //    }
65     /*
66      * @Override public int hashCode() { final int prime = 31; int result = 1;
67      * result = prime * result + age; result = prime * result + ((name == null) ? 0
68      * : name.hashCode()); return result; }
69      *
70      * @Override public boolean equals(Object obj) { if (this == obj) return true;
71      * if (obj == null) return false; if (getClass() != obj.getClass()) return
72      * false; Person other = (Person) obj; if (age != other.age) return false; if
73      * (name == null) { if (other.name != null) return false; } else if
74      * (!name.equals(other.name)) return false; return true; }//alt+shift+s
75      * hashCode和equals
76      */
77     public String getName() {
78         return name;
79     }
80     public void setName(String name) {
81         this.name = name;
82     }
83     public int getAge() {
84         return age;
85     }
86     public void setAge(int age) {
87         this.age = age;
88     }
89
90     @Override
91     public String toString() {
92         return "Person:"+getName()+":"+getAge();
93     }
94
95
96 }

Person

 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     @Override
16     public String toString() {
17         // TODO Auto-generated method stub
18         return "Student:"+getName()+":"+getAge();
19     }
20
21 }

Student

 1 package cn.itcast.p3.comparator;
 2
 3 import java.util.Comparator;
 4
 5 import cn.itcast.p2.bean.Person;
 6
 7 public class ComparatorByName implements Comparator<Person> {//ctrl+1快速实现方法
 8
 9     @Override
10     public int compare(Person o1, Person o2) {
11         // TODO Auto-generated method stub
12         int temp = o1.getName().compareTo(o2.getName());
13         return temp==0?o1.getAge()-o2.getAge():temp;
14     }
15
16 }

ComparatorByName