1 import java.util.Collections;
2 import java.util.Comparator;
3 import java.util.LinkedList;
4
5 class Person{
6 private float height;
7 private String name;
8
9 Person(float height)
10 {
11 this.height=height;
12 }
13
14 public float getHeight() {
15 return height;
16 }
17
18 public void setHeight(float height) {
19 this.height = height;
20 }
21
22 public String getName() {
23 return name;
24 }
25
26 public void setName(String name) {
27 this.name = name;
28 }
29 }
30
31 class PersonHeight implements Comparator<Person>{
32
33 @Override
34 public int compare(Person e1, Person e2) {
35 if(e1.getHeight() < e2.getHeight()){
36 return 1;
37 } else {
38 return -1;
39 }
40 }
41 }
42
43
44 public class Question3 {
45
46 public static void main(String[] args) {
47 Person p1=new Person(23.4f);
48 p1.setName("Stud1");
49 Person p2=new Person(2.34f);
50 p2.setName("Stud2");
51 Person p3=new Person(34.32f);
52 p3.setName("Stud3");
53 Person p4=new Person(56.45f);
54 p4.setName("Stud4");
55 Person p5=new Person(21.4f);
56 p5.setName("Stud5");
57
60 LinkedList<Person> al=new LinkedList<Person>();
61 al.add(p1);
62 al.add(p2);
63 al.add(p3);
64 al.add(p4);
65 al.add(p5);
66
67
68
69 Collections.sort(al,new PersonHeight());
70 for(Person p:al)
71 System.out.println(p.getName()+" "+p.getHeight());
72
73 }
74
75 }
Collections.sort(al,new PersonHeight());
结果：
Stud4 56.45
Stud3 34.32
Stud1 23.4
Atud5 21.4
Stud2 2.34
1 package com.cn.aug26;
2
3
4 import java.util.Collections;
5 import java.util.LinkedList;
6 7
8 class Person1 implements Comparable <Person1>{
9 private Float height;
10 private String name;
11
12 Person1(float height)
13 {
14 this.height=height;
15 }
16
17 public Float getHeight() {
18 return height;
19 }
20
21 public void setHeight(float height) {
22 this.height = height;
23 }
24
25 public String getName() {
26 return name;
27 }
28
29 public void setName(String name) {
30 this.name = name;
31 }
32
33 @Override
34 public int compareTo(Person1 p) {
35 if(this.getHeight()<p.getHeight()){
36 return 1;
37
38 }else if(this.getHeight()>p.getHeight()){
39 return -1;
40 }else{
41 return 0;
42 }
43
44 }
45 }
46
47
48 public class Question3_1 {
49
50 public static void main(String[] args) {
51 Person1 p1=new Person1(23.4f);
52 p1.setName("Stud1");
53 Person1 p2=new Person1(2.34f);
54 p2.setName("Stud2");
55 Person1 p3=new Person1(34.32f);
56 p3.setName("Stud3");
57 Person1 p4=new Person1(56.45f);
58 p4.setName("Stud4");
59 Person1 p5=new Person1(21.4f);
60 p5.setName("Stud5");
61
62 LinkedList<Person1> al=new LinkedList<Person1>();
63
64 al.add(p1);
65 al.add(p2);
66 al.add(p3);
67 al.add(p4);
68 al.add(p5);
69
70 Collections.sort(al);//降序
71
72 for(Person1 p:al)
73 System.out.println(p.getName()+" "+p.getHeight());
74
75 }
76
77 }
结果：
Stud4 56.45
Stud3 34.32
Stud1 23.4
Stud5 21.4
Stud2 2.34
Collections.sort(al,Collections.reverseOrder());//升序
结果：
Stud2 2.34
Stud5 21.4
Stud1 23.4
Stud3 34.32
Stud4 56.45
若身高相同，比较姓名，修改compareTo 方法：
1 @Override
2 public int compareTo(Person1 p) {
3 if(this.getHeight()<p.getHeight()){
4 return 1;
5
6 }else if(this.getHeight()>p.getHeight()){
7 return -1;
8 }else{
9 return this.name.compareTo(p.name);
10 }
11
12 }
