JAVA高级教程Java TreeMap表达式(8)

public class Students implements Comparable<Students>{
    private String name;
    private  int stuNO;

    public Students() {
    }

    public Students(String age, int stuNO) {
        this.name = age;
        this.stuNO = stuNO;
    }

    public String getName() {
        return name;
    }

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

    public int getStuNO() {
        return stuNO;
    }

    public void setStuNO(int stuNO) {
        this.stuNO = stuNO;
    }

    @Override
    public String toString() {
        return "Students{" +
                "age='" + name + '\'' +
                ", stuNO=" + stuNO +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Students students = (Students) o;
        return stuNO == students.stuNO && Objects.equals(name, students.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, stuNO);
    }

    @Override
    public int compareTo(Students o) {
        int n1=this.name.compareTo(o.getName());
        int n2=this.stuNO-o.getStuNO();
        return n2;
    }
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package Map01;

import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;

public class Demo03_TreeMap {
    public static void main(String[] args) {
        TreeMap<Students,String> stu=new TreeMap<>();


        Students p1=new Students("刘德华",20);
        Students p2=new Students("李小龙",22);
        Students p3=new Students("彭于晏",24);

        System.out.println("数据的个数"+stu.size());
        System.out.println(stu.toString());

        stu.put(p1,"上海");
        stu.put(p2,"北京");
        stu.put(p3,"深圳");
        //重写了hascode就不会重读
        stu.put(new Students("彭于晏",24),"深圳");


        System.out.println("数据的个数"+stu.size());
        System.out.println(stu.toString());


        //删除
        stu.remove(p1);


        //遍历
        //使用keyset
        System.out.println("============使用keyset======================");
//        Set keys= map.keySet();
        for (Students key : stu.keySet()) {
            System.out.println(key+":"+stu.get(key));
        }

        //使用entryset遍历
        System.out.println("============使用entryset遍历======================");
//        Set> entries=map.entrySet();
        for (Map.Entry<Students, String> entry : stu.entrySet()) {
            System.out.println(entry.getKey()+":"+entry.getValue());

        }

    }
}
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