对TreeSet中存储的自定义类的对象进行排序

对TreeSet中存储的自定义类的对象进行排序

步骤:

• 1 自定义类实现Comparable接口,重写compareTo方法
• 2 方法内:
  主要条件:按照学生的总成绩进行排序（从高到低）
  次要条件:总成绩相同，排序数学成绩；数学成绩相同，排序语文成绩；语文成绩相同，排序年龄；年龄相同，排序姓名（姓名排序使用的是String类的compareTo方法,内部计算字符的码表差值[0-9A-Za-z]）

Case_Student类：

package my_set.my_set_case;
public class Case_Student implements Comparable<Case_Student>{
    private String name;
    private int age;
    private int mathScore;
    private int ChineseScore;
    private int EnglishScore;
    private int allScore ;

    public Case_Student() {
    }

    public Case_Student(String name, int age, int mathScore, int chineseScore, int englishScore) {
        this.name = name;
        this.age = age;
        this.mathScore = mathScore;
        this.ChineseScore = chineseScore;
        this.EnglishScore = englishScore;
        this.allScore = mathScore + chineseScore + englishScore;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public int getMathScore() {
        return mathScore;
    }

    public void setMathScore(int mathScore) {
        this.mathScore = mathScore;
    }

    public int getChineseScore() {
        return ChineseScore;
    }

    public void setChineseScore(int chineseScore) {
        ChineseScore = chineseScore;
    }

    public int getEnglishScore() {
        return EnglishScore;
    }

    public void setEnglishScore(int englishScore) {
        EnglishScore = englishScore;
    }

    public int getAllScore() {
        return allScore;
    }

    public void setAllScore(int allScore) {
        this.allScore = allScore;
    }

    @Override
    public String toString() {
        return "Cast_Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", mathScore=" + mathScore +
                ", ChineseScore=" + ChineseScore +
                ", EnglishScore=" + EnglishScore +
                ", allScore=" + allScore +
                '}';
    }

    @Override
    public int compareTo(Case_Student o) {
        int i = o.getAllScore() - this.getAllScore();
        if (i==0){
            i = o.getMathScore() - this.getMathScore();
        }
        if (i==0){
            i = o.getChineseScore() - this.getChineseScore();
        }
        if (i==0){
            i = o.getAge() - this.getAge();
        }
        if (i==0){
            i = o.getName().compareTo(this.getName());
        }
        return i;
    }
}

Case_Test类：

package my_set.my_set_case;

//先比较总成绩，按照从大到小排序；如果相同，排序数学成绩；如果相同，排序语文成绩；如果相同，排序年龄；如果相同，排序姓名
import java.util.TreeSet;

public class Case_Test {
    public static void main(String[] args) {
        TreeSet<Case_Student> students = new TreeSet<Case_Student>();
        students.add(new Case_Student("张三",18,86,84,85));
        students.add(new Case_Student("李四",19,90,84,91));
        students.add(new Case_Student("王五",21,99,100,60));
        students.add(new Case_Student("张三",18,86,84,85));
        students.add(new Case_Student("老六",18,84,86,85));
        students.add(new Case_Student("老八",17,84,86,85));


        for (Case_Student student : students) {
            System.out.println(student);
        }
    }
}