[数据结构与算法](JAVA)红黑树之自然顺序排序和自定义排序方式

package cn.book.objectarr;

/**
 * @author alina
 * @date 2021年08月22日 6:57 下午
 */
public class Student implements Comparable<Student> {
    private String name;
    private int age;
    public Student(){}
    /***
     *
     * @author Alina
     * @date 2021/9/21 9:41 下午
     * @param o
     * @return int
     * 使用构造方法的自然排序方式
     */
    public  int compareTo(Student o ){
        //String类自带comparaTo();
        int num = this.name.compareTo(o.name);
        return num==0?this.age - o.age:num;
//        if(num==0){
//            return this.age - o.age;
//        }else{
//            return num;
//        }
    }
    public Student(String name,int age){
         this.age = age;
         this.name = name;
    }

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return this.age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    public String toString(){
        return "Student"+" "+name+" "+age;

    }
    public boolean equals(Object o){
        if (o == null) {
            return false;
        }
        else if(this == o){
            return true;}
        else if (o instanceof Student){
            Student s = (Student) o;
            return this.name.equals(s.name) && this.age == s.age;
        }
        return false;

    }
    public int hasCode(){
        return name.hashCode() +age*39;
    }

}

public class TreeSetDemo {
    public static void main(String[] args) {
        //以姓名为顺序排序；
        method_1();
        
        //以年龄为顺序排序
        method_2();
    }
    public static void method_1(){
        TreeSet<Student> tr =  new TreeSet<>();
        tr.add(new Student("zhangsan",12));
        tr.add(new Student("lisi",13));
        tr.add(new Student("wanger",56));
        tr.add(new Student("lisi",14));
        Iterator it = tr.iterator();
        while (it.hasNext()){
            System.out.println(it.next());
        }
    }

package cn.book.objectarr;

import java.util.Comparator;
import java.util.Iterator;
import java.util.TreeSet;

/**
 * @author Alina
 * @date 2021年09月21日 8:50 下午
 */
class myCompatato implements Comparator<Student>{
    @Override
    public int compare(Student o1, Student o2) {
        int age = o1.getAge() - o2.getAge();
        return age == 0? o1.getName().compareTo(o2.getName()):age;

    }
}
public class TreeSetDemo {
    public static void main(String[] args) {
        //以年龄为顺序排序
        method_2();
    }
   
    public static void method_2(){
        TreeSet<Student> tr =  new TreeSet<>( new myCompatato());
        tr.add(new Student("zhangsan",12));
        tr.add(new Student("lisi",13));
        tr.add(new Student("wanger",56));
        tr.add(new Student("lisi",14));
        Iterator it = tr.iterator();
        while (it.hasNext()){
            System.out.println(it.next());
        }
    }

    }

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