JavaSE-15.2.4【案例-成绩排序（比较器排序Comparator实现、自然排序Comparable实现）】 

 1 package day6.lesson2.anli1;
 2 
 3 import java.util.Comparator;
 4 import java.util.TreeSet;
 5 
 6 /*
 7 2.4 案例-成绩排序
 8 
 9     用TreeSet集合存储多个学生信息(姓名，语文成绩，数学成绩)，并遍历该集合
10     要求：按照总分从高到低出现
11 
12     通过 比较器排序Comparator 实现
13     通过 自然排序Comparable 实现
14  */
15 //通过 比较器排序Comparator 实现
16 public class TreeSetDemo4 {
17     public static void main(String[] args) {
18         TreeSet<Student> ts = new TreeSet<>(new Comparator<Student>() {
19             @Override
20             public int compare(Student s1, Student s2) {
21 //                return 0;
22 
23                 /*int score_s1 = s1.getChinese() + s1.getMath();
24                 int score_s2 = s2.getChinese() + s2.getMath();
25                 int num = score_s2 - score_s1;
26                 return num;*/
27 
28                 int num = s2.getSum() - s1.getSum();
29                 int num2 = ( num==0 ? s1.getChinese()-s2.getChinese() : num );
30                 int num3 = ( num2==0 ? s1.getName().compareTo(s2.getName()) : num2 );
31                 return num3;
32             }
33         });
34 
35         Student s1 = new Student("tom", 100, 80);
36         Student s2 = new Student("amy", 85, 90);
37         Student s3 = new Student("sam", 79, 100);
38         Student s4 = new Student("jji", 90, 95);
39         Student s5 = new Student("bba", 95, 90);
40         Student s6 = new Student("cca", 95, 90);
41 
42         ts.add(s1);
43         ts.add(s2);
44         ts.add(s3);
45         ts.add(s4);
46         ts.add(s5);
47         ts.add(s6);
48 
49         for (Student s: ts){
50 //            System.out.println(s.getName() + "," + (s.getChinese()+s.getMath()) );
51             System.out.println(s.getName() + "," + s.getSum());
52         }
53         /*
54         jji,185
55         bba,185
56         cca,185
57         tom,180
58         sam,179
59         amy,175
60          */
61     }
62 }
 1 package day6.lesson2.anli1;
 2 
 3 public class Student {
 4 
 5     private String name;
 6     private int chinese;
 7     private int math;
 8 
 9     public Student() {
10     }
11 
12     public Student(String name, int chinese, int math) {
13         this.name = name;
14         this.chinese = chinese;
15         this.math = math;
16     }
17 
18     public void setName(String name) {
19         this.name = name;
20     }
21 
22     public void setChinese(int chinese) {
23         this.chinese = chinese;
24     }
25 
26     public void setMath(int math) {
27         this.math = math;
28     }
29 
30     public String getName() {
31         return name;
32     }
33 
34     public int getChinese() {
35         return chinese;
36     }
37 
38     public int getMath() {
39         return math;
40     }
41 
42     public int getSum(){
43         return this.chinese + this.math;
44     }
45 }
 1 package day6.lesson2.anli1_1;
 2 
 3 import java.util.TreeSet;
 4 
 5 //通过 自然排序Comparable 实现
 6 public class TreeSetDemo5 {
 7     public static void main(String[] args) {
 8         TreeSet<Student> ts = new TreeSet<>();
 9 
10         Student s1 = new Student("tom", 100, 80);
11         Student s2 = new Student("amy", 85, 90);
12         Student s3 = new Student("sam", 79, 100);
13         Student s4 = new Student("jji", 90, 95);
14         Student s5 = new Student("bba", 95, 90);
15         Student s6 = new Student("cca", 95, 90);
16 
17         ts.add(s1);
18         ts.add(s2);
19         ts.add(s3);
20         ts.add(s4);
21         ts.add(s5);
22         ts.add(s6);
23 
24         for (Student s: ts){
25             System.out.println(s.getName() + "," + s.getSum());
26         }
27         /*
28         jji,185
29         bba,185
30         cca,185
31         tom,180
32         sam,179
33         amy,175
34          */
35     }
36 }
 1 package day6.lesson2.anli1_1;
 2 
 3 public class Student implements Comparable<Student>{
 4 
 5     private String name;
 6     private int chinese;
 7     private int math;
 8 
 9     public Student() {
10     }
11 
12     public Student(String name, int chinese, int math) {
13         this.name = name;
14         this.chinese = chinese;
15         this.math = math;
16     }
17 
18     public void setName(String name) {
19         this.name = name;
20     }
21 
22     public void setChinese(int chinese) {
23         this.chinese = chinese;
24     }
25 
26     public void setMath(int math) {
27         this.math = math;
28     }
29 
30     public String getName() {
31         return name;
32     }
33 
34     public int getChinese() {
35         return chinese;
36     }
37 
38     public int getMath() {
39         return math;
40     }
41 
42     public int getSum(){
43         return this.chinese + this.math;
44     }
45 
46     @Override
47     public int compareTo(Student s) {
48 //        return 0;
49 
50         int num = s.getSum() - this.getSum();
51         int num2 = ( num==0 ? this.getChinese()-s.getChinese() : num);
52         int num3 = ( num2==0 ? this.getName().compareTo(s.getName()) : num2 );
53         return num3;
54     }
55 }

 

posted @ 2021-06-01 13:22  yub4by  阅读(75)  评论(0)    收藏  举报