TreeSet第二种排序方法（比较器排序）

代码实现：import java.util.Comparator;
import java.util.TreeSet;

public class TreeSet排序方法 {
    public static void main(String[] args) {
        TreeSet<String> treeSet=new TreeSet<>(new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                int i=o1.length()-o2.length();
              i=i==0?o1.compareTo(o2):i;
                return i;
            }
        });
        treeSet.add("a");
        treeSet.add("ab");
        treeSet.add("df");
        treeSet.add("aweq");
        System.out.println(treeSet);
    }
}

mport java.util.TreeSet;

public class treeset练习 {
    public static void main(String[] args) {
        student2 s1 = new student2("张三", 23, 90, 99, 50);
        student2 s2 = new student2("李四", 24, 90, 98, 50);
        student2 s3 = new student2("王五", 25, 95, 100, 30);
        student2 s4 = new student2("赵六", 26, 60, 99, 70);
        student2 s5 = new student2("钱七", 26, 70, 80, 70);
        TreeSet<student2> treeSet=new TreeSet<>();
        treeSet.add(s1);
        treeSet.add(s2);
        treeSet.add(s3);
        treeSet.add(s4);
        treeSet.add(s5);
       // System.out.println(treeSet);//直接打印未定义排序方法会报错
        for (student2 student2 : treeSet) {
            System.out.println(student2);
        }
    }
}
class student2 implements Comparable<student2> {
    private String name;
    private  int age;
    private int chinese;
    private int math;
    private  int english;

    public student2(String name, int age, int chinese, int math, int english) {
        this.name = name;
        this.age = age;
        this.chinese = chinese;
        this.math = math;
        this.english = english;
    }

    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 getChinese() {
        return chinese;
    }

    public void setChinese(int chinese) {
        this.chinese = chinese;
    }

    public int getMath() {
        return math;
    }

    public void setMath(int math) {
        this.math = math;
    }

    public int getEnglish() {
        return english;
    }

    public void setEnglish(int english) {
        this.english = english;
    }

    @Override
    public String toString() {
        return "student2{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", chinese=" + chinese +
                ", math=" + math +
                ", english=" + english +
                '}';
    }

    @Override
    public int compareTo(student2 o) {
        int sum1=this.getChinese()+this.math+this.getEnglish();
        int sum2=o.getChinese()+o.math+o.getEnglish();
        int i=sum1-sum2;
        //比较两者总分
        i=i==0?this.getChinese()-o.getChinese():i;
        //总分一样按照语文排序
           i=i==0?this.getMath()-o.getMath():i;
           //    //数学一样按照语文排序
           i=i==0?this.getEnglish()-this.getEnglish():i;
           i=i==0?this.getAge()-o.getAge():i;
           i=i==0?this.getName().compareTo(o.getName()):i;
        return i;
    }
}

小结：