Java 21-11-19

Studentz类

package com.jk.p235;

import java.util.Objects;
public class Studentz {

    String id;//学号
    String name;//姓名
    int score;//成绩

    public Studentz() {

    }
    public Studentz(String id, String name, int score) {
        this.id = id;
        this.name = name;
        this.score = score;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public double getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }

    @Override
    public String toString() {
        return "id=" + id +
                ", name='" + name + ''' +
                ", score=" + score +"n";
    }
    public void show(){
        System.out.println(id+"t"+name+"tt"+score);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Studentz)) return false;
        Studentz studentz = (Studentz) o;
        return id.equals(studentz.id);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id);
    }
}

StudentTest类

package com.jk.p235;

import java.security.KeyStore;
import java.util.*;
public class TestStudentz {
    public static void main(String[] args) {
        Studentz stu1=new Studentz("1001","张三",80);
        Studentz stu2=new Studentz("1002","李四",90);
        Studentz stu3=new Studentz("1003","王五",66);
        Studentz stu4=new Studentz("1004","王岩",88);
        Studentz stu5=new Studentz("1005","啊扣",99);
        Set set1=new HashSet<>();
        set1.add(stu1);
        set1.add(stu2);
        set1.add(stu3);
        set1.add(stu4);
        set1.add(stu5);
        for(Studentz G:set1){
            System.out.println(G.toString());
        }

        Map map1= new HashMap<>();
        map1.put("1001","张三");
        map1.put("1002","李四");
        map1.put("1003","王五");
        map1.put("1004","王岩");
        map1.put("1005","啊扣");
        System.out.println("----------通过Map集合-----------");
        System.out.println("1001="+map1.get("1001"));
        System.out.println("1002="+map1.get("1002"));
        System.out.println("1003="+map1.get("1003"));
        System.out.println("1004="+map1.get("1004"));
        System.out.println("1005="+map1.get("1005"));

        System.out.println("map1集合中的键"+map1.keySet());
        System.out.println("map1集合中的值"+map1.values());

        //打印键集合
        System.out.println("----使用 for-each 循环遍历 key 和 values----");
        for(String key: map1.keySet()){
            System.out.println(key);
        }
        //打印值集合
        for(String value: map1.values()){
            System.out.println(value);
        }

        System.out.println("----在 for 循环中使用 entries 实现 Map 的遍历----");
        for(Map.Entry entry: map1.entrySet()){
            String mapKey = entry.getKey();
            String mapValue = entry.getValue();
            System.out.println(mapKey + "：" + mapValue);
        }

        System.out.println("----使用迭代器（Iterator）遍历----");
        Iterator>entries=map1.entrySet().iterator();
        while (entries.hasNext()) {
            Map.Entry entry = entries.next();
            String key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key + ":" + value);
        }


        Studentz[] arr = new Studentz[5];
        arr[0] = new Studentz("1001", "张三", 80);
        arr[1] = new Studentz("1002", "李四", 90);
        arr[2] = new Studentz("1003", "王五", 66);
        arr[3] = new Studentz("1004", "王岩", 88);
        arr[4] = new Studentz("1005", "啊扣", 99);

        sortStudentz(arr);
        System.out.println("------------toString输出-----------");//将排序后的结果通过toString方法输出
        System.out.println(Arrays.toString(arr));

        System.out.println("-----------遍历输出-----------");//将排序后的结果通过遍历输出
        System.out.println("idtt" + "namet" + "score");
        for (Studentz S : arr) {
            S.show();
        }
        //将按照成绩排序好的数据存入ArrayList集合中
        List list = new ArrayList<>(Arrays.asList(arr));
        System.out.println("------------ArrayList------------");
        for (Studentz F : list) {
            System.out.println(F);
        }
        //将按照成绩排序好的数据存入HashSet集合中
        Set set = new HashSet<>(Arrays.asList(arr));
        System.out.println("----------HashSet------------");
        for (Studentz T : set) {
            System.out.println(T);
        }
    }

    //排序方法
    public static void sortStudentz(Studentz[] arr) {
        for (int i = 0; i < arr.length - 1; i++) {
            for (int j = 0; j < arr.length - 1 - i; j++) {
                if (arr[j].getScore() < arr[j + 1].getScore()) {
                    Studentz temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
    }
}

此为21年11月18日作业，于次日完成
里面都有注释，不懂得可以私信作者。