老师，有什么方法转换成班级类吗？不通过searchByName这个方法，直接转换的有吗？

import java.util.*;

public class Stutent_TestDemo {
    public void Student_test(){
//        Student st1=new Student(001,"张三",88.0f,99.7f);
//        Student st2=new Student(002,"李四",86.0f,90.7f);
//        Student st3=new Student(003,"王五",60.0f,78.7f);
//        List<Student> st=new ArrayList<Student>();
//        Collections.addAll(st,st1,st2,st3);
//        for (Student stone:st){
//            System.out.println(stone);
//        }
    }

    public void Banji_test(){
        Student st1=new Student(001,"张三",88.0f,99.7f);
        Student st2=new Student(002,"李四",86.0f,90.7f);
        Student st3=new Student(002,"王五",60.0f,78.7f);
        BanJi bj=new BanJi("701班级","高一年纪");
        bj.addStudent(st1);
        bj.addStudent(st2);
        //bj.addStudent(st3);
        bj.displayAllStudent();
        System.out.println("++++++");
        Student student=bj.searchStudentByNum(006);
        if(student==null){
            System.out.println("学号不存在");
        }else {
            System.out.println(student);
            }
        System.out.println("++++++");
        bj.insertChineseScore(002,99.5f);
//        bj.insertMathScore(002,77f);
        bj.deleteStudent(001);
        bj.displayAllStudent();
        }

    public void schooi_test(){
        Student st1=new Student(001,"张三",100.0f,60.7f);
        Student st2=new Student(002,"李四",330.0f,100.7f);
        Student st3=new Student(003,"王五",200.0f,200.7f);
        BanJi bj1=new BanJi("701班级","高一年纪");
        BanJi bj2=new BanJi("601班级","高二年纪");

        bj1.addStudent(st1);
        bj1.addStudent(st2);
        bj2.addStudent(st3);
        School sh=new School();
        sh.addBanji(bj1);
        sh.addBanji(bj2);

        //BanJi s=sh.searchByName("高一年纪");
        //System.out.println(s);
//        System.out.println("=============");
//        sh.sortChineseByAverage();
//        System.out.println("=============");
//        sh.sortMathByAverage();
        sh.displayBanJiName();

    }


    public void mainMenu() {
        System.out.println("**********************************");
        System.out.println("               **主菜单**");
        System.out.println("              1--班级管理");
        System.out.println("              2--学校管理");
        System.out.println("              0--退出");
        System.out.println("**********************************");
        System.out.println("请输入操作选项：");
    }

    public void banJiMenu() {
        System.out.println("******************************************************");
        System.out.println("                           **班级管理**");
        System.out.println("              1--添加学生信息到主班级列表");
        System.out.println("              2--添加学生信息到普通班级");
        System.out.println("              3--通过学号查询学生信息");
        System.out.println("              4--输入班级的语文成绩");
        System.out.println("              5--输入班级的数学成绩");
        System.out.println("              6--删除学生信息");
        System.out.println("              7--显示所有学生信息");
        System.out.println("              9--返回上一级菜单");
        System.out.println("******************************************************");
        System.out.println("请输入操作选项：");
    }

    public void schoolMenu() {
        System.out.println("******************************************************");
        System.out.println("                           **学校管理**");
        System.out.println("              1--创建班级");
        System.out.println("              2--删除班级");
        System.out.println("              3--通过班级名查询班级信息");
        System.out.println("              4--对各班语文成绩进行从大到小排序");
        System.out.println("              5--对各班数学成绩进行从大到小排序");
        System.out.println("              6--显示所有班级名称");
        System.out.println("              9--返回上一级菜单");
        System.out.println("******************************************************");
        System.out.println("请输入操作选项：");
    }




    public void TestDeme(){
        BanJi zbj=new BanJi("S001","主班级");
        School shl=new School();
        Stutent_TestDemo st=new Stutent_TestDemo();
        Scanner sc=new Scanner(System.in);
        int input1,input2,input3;
        while (true){
            st.mainMenu();
            input1=sc.nextInt();
            if(input1==0){
                System.out.println("成功退出");
                break;
            }
            switch (input1){
                case 1:
                    while (true){
                    st.banJiMenu();
                    System.out.println("请输入对应的数字对播放列表进行管理：");
                    input2=sc.nextInt();
                        if(input2==9){
                            System.out.println("成功返回上一级菜单");
                            break;
                        }
                        switch (input2){
                            case 1:
                                int input4;
                                System.out.println("请输入需要添加学生的人数");
                                input4=sc.nextInt();
                                for (int i=0;i<input4;i++){
                                    System.out.println("请输入学号");
                                    int a1=sc.nextInt();
                                    System.out.println("请输入学生姓名");
                                    String a2=sc.next();
                                    Float f01,f02;
                                    Student sj=new Student(a1,a2,f01=0.0f,f02=0.0f);
                                    zbj.addStudent(sj);
                            }
                                //zbj.addStudent();
                                continue;
                            case 2:
                                System.out.println("请输入需要添加的班级名称");
                                String bjname=sc.next();
                                BanJi bj1=shl.searchByName(bjname);
                                if(bj1 == null){
                                    System.out.println("请先创建班级，"+bjname+"该班级不存在");
                                    continue;
                                }else {
                                    System.out.println("请输入需要添加的数量");
                                    int b1=sc.nextInt();
                                    for (int i=0;i<b1;i++){
                                        System.out.println("请先输入学号");
                                        int b2=sc.nextInt();
                                        Student zbj2=zbj.searchStudentByNum(b2);
                                        if(zbj2 ==null){
                                            System.out.println("请输入学生姓名");
                                            String b3=sc.next();
                                            float b4,b5;
                                            Student sd=new Student(b2,b3,b4=0.0f,b5=0.0f);
                                            bj1.addStudent(sd);
                                            zbj.addStudent(sd);
                                        }else {
                                            bj1.addStudent(zbj2);
                                            }
                                        }
                                    //BanJi s=bj1;
                                    zbj.displayAllStudent();

                                }

                                shl.searchByName(bjname);
                                continue;
                            case 3:
                                System.out.println("请输入学号");
                                int stuNumt=sc.nextInt();
                                Student stuNumone=zbj.searchStudentByNum(stuNumt);
                                if(stuNumone ==null){
                                    System.out.println("学号不存在");
                                    break;
                                }else {
                                    System.out.println(stuNumone);
                                }
                                continue;
                            case 4:
                                System.out.println("请输入需要添加语文成绩学生的学号");
                                int s1=sc.nextInt();
                                Student s2=zbj.searchStudentByNum(s1);
                                if(s2==null){
                                    System.out.println("学号不存在");
                                    break;
                                }else {
                                    System.out.println("请输入需要语文分数");
                                    float f1=sc.nextFloat();
                                    zbj.insertChineseScore(s1,f1);

                                }
                                continue;
                            case 5:
                                System.out.println("请输入需要添加数学成绩学生的学号");
                                int s3=sc.nextInt();
                                Student s4=zbj.searchStudentByNum(s3);
                                if(s4 == null){
                                    System.out.println("输入的学号不存在");
                                    break;
                                }else {
                                    System.out.println("请输入需要添加的数学成绩");
                                    float sf1=sc.nextFloat();
                                    zbj.insertMathScore(s3,sf1);
                                }
                                continue;
                            case 6:
                                System.out.println("输入需要删除学生的学号");
                                int s5=sc.nextInt();
                                Student sd1=zbj.searchStudentByNum(s5);
                                if(sd1==null){
                                    System.out.println("你输入的删除的学号不存在");
                                    break;
                                }else {
                                    zbj.deleteStudent(s5);
                                }
                                continue;
                            case 7:
                                zbj.displayAllStudent();
                                continue;
                        }

                    }
                    break;

                case 2:
                    while (true){
                        st.schoolMenu();
                        System.out.println("请输入对应的操作");
                        input3=sc.nextInt();
                        if (input3==9){
                            System.out.println("成功返回上一页");
                            break;
                        }
                        switch (input3){
                            case 1:
                                System.out.println("请输入班级id");
                                String a1=sc.next();
                                System.out.println("请输入班级名称");
                                String a2=sc.next();
                                BanJi a3=new BanJi(a1,a2);
                                shl.addBanji(a3);
                                break;
                            case 2:
                                System.out.println("请输入需要删除的班级名称");
                                String st1=sc.next();
                                BanJi bj1=shl.searchByName(st1);
                                if(bj1==null){
                                    System.out.println("输入的班级不存在");
                                    break;
                                }else if(bj1.equals("主班级")){
                                    System.out.println("主班级无法删除");
                                    break;
                                }else {
                                    shl.deleteBanji(st1);
                                }
                                break;
                        }

                    }
                    break;
                default:
                    System.out.println("输入不正确，请重新输入");
                    break;


            }





        }




    }





    public static void main(String[] args) {
        Stutent_TestDemo st=new Stutent_TestDemo();
        //st.Student_test();
        //st.Banji_test();
        //st.schooi_test();
        st.TestDeme();

    }
}



import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class BanJi implements Comparable{
    private String classId;
    private String className;
    private List<Student> studentslist;


    public BanJi(String classId,String className){
        this.setClassId(classId);
        this.setClassName(className);
        studentslist=new ArrayList<Student>();
    }

    /**
     * 将学生添加到班级
     * @param stu
     */
    public void addStudent(Student stu){
        boolean fals=false;
        for(Student st:studentslist){
            if(st.getStuNum()==stu.getStuNum()){
                fals=true;
                break;
            }
        }
        if(fals){
            System.out.println(stu.getStuName()+"学号重复");
        }else {
            studentslist.add(stu);
        }

    }

    /**
     *
     * @param stuNum
     * @return 通过学号查询学生在班级中是否存在
     */
    public Student searchStudentByNum(int stuNum){
        Student stuNum1=null;
        for (Student st:studentslist){
            if(st.getStuNum()==stuNum){
                stuNum1=st;
                break;
            }
        }
        return stuNum1;
    }

    /**
     * 输入班级学生的语文成绩
     * @param stuNum
     * @param score
     */
    public void insertChineseScore(int stuNum,float score){
        Student st=searchStudentByNum(stuNum);
        for (Student s:studentslist){
            if(s.getStuNum()==stuNum){
                s.setChinese(score);
                System.out.println(s);
                break;
            }
        }

    }

    /**
     * 输入班级学生的数学成绩：
     * @param stuNum
     * @param score
     */
    public void insertMathScore(int stuNum,float score){
        for(Student st:studentslist){
            if(st.getStuNum()==stuNum){
                st.setMath(score);
                System.out.println(st);
                break;
            }
        }
    }

    /**
     * 删除学生信息
     * @param stuNum
     */
    public void deleteStudent(int stuNum){
       Student st=searchStudentByNum(stuNum);
       studentslist.remove(st);
       System.out.println("学号"+stuNum+"删除成功");
    }

    /**
     * 显示所有学生的信息（包括学号和姓名）
     */
    public void displayAllStudent(){
        for (Student list:studentslist){
            System.out.println(list);
        }
    }

    //获取语文成绩平均分
    public float yuwen(){
        float ft=0.0f;
        for(Student stu:studentslist){
            ft=ft+stu.getChinese();
            break;
        }
        return ft/studentslist.size();
    }

    //数学成绩平均分
    public float shuxue(){
        float ft=0.0f;
        for (Student stu:studentslist){
            ft=ft+stu.getMath();
        }
        return ft/studentslist.size();
    }



    public String getClassId() {
        return classId;
    }

    public void setClassId(String classId) {
        this.classId = classId;
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public List<Student> getStudentslist() {
        return studentslist;
    }

    public void setStudentslist(List<Student> studentslist) {
        this.studentslist = studentslist;
    }

    @Override
    public String toString() {
        return "班级{" +
                "班级Id='" + classId + '\'' +
                ", 班级名称='" + className + '\'' +
                ", 班级列表=" + studentslist +
                '}';
    }


    @Override
    public int compareTo(Object o) {
        return 0;
    }
}







import java.util.*;
import java.util.stream.Stream;

public class School{
    Map<String,BanJi>schoolMap;

    public School(){
        schoolMap=new HashMap<String,BanJi>();
    }

    /**
     * 添加班级
     * @param banji
     */
    public void addBanji(BanJi banji){
       schoolMap.put(banji.getClassName(),banji);
    }

    /**
     * 删除班级
     * @param banji
     */
    public void deleteBanji(BanJi banji){
        schoolMap.remove(banji.getClassName());
        System.out.println("已经成功删除班级"+banji);
    }

    /**
     * 通过班级名称查询班级
     * @param className
     * @return
     */
    public BanJi searchByName(String className) {
        BanJi bj=null;
        Set<String> setbanji=schoolMap.keySet();
        for(String se:setbanji){
            if(se.equals(className)){
                bj=schoolMap.get(se);
                break;
            }
        }
        return bj;
    }

    /**
     * 对各班语文成绩按平均分进行由大到小排序：
     */
    public void sortChineseByAverage() {
       List<BanJi> listbj=new ArrayList<>();
       Iterator<BanJi> itbj=schoolMap.values().iterator();
       while (itbj.hasNext()){
           listbj.add(itbj.next());
       }
       System.out.println("未排序前"+listbj);
       Collections.sort(listbj,new YuWen());
       for (BanJi li:listbj){
           System.out.println("排序后"+li);
           System.out.println("该班语文平均分为："+li.yuwen());
       }


    }

    public void sortMathByAverage() {
        List<BanJi> listbj=new ArrayList<>();
        Iterator<BanJi> itbj=schoolMap.values().iterator();
        while (itbj.hasNext()){
            listbj.add(itbj.next());
        }
        Collections.sort(listbj,new ShuXue());
        for (BanJi li:listbj){
            System.out.println("排序后"+li);
            System.out.println("数学平均成绩"+li.shuxue());
        }
    }

    /**
     * 显示所有班级名称
     */
    public void displayBanJiName() {
        Set<String> setlist=schoolMap.keySet();
        for (String se:setlist){
            System.out.println(se);
        }
    }





    public Map<String, BanJi> getSchoolMap() {
        return schoolMap;
    }

    public void setSchoolMap(Map<String, BanJi> schoolMap) {
        this.schoolMap = schoolMap;
    }



}





import java.util.Objects;

public class Student {
    private int stuNum;
    private String stuName;
    private float math;
    private float chinese;


    public Student(){}
    /**
     *
     * @param stuNum 学号
     * @param stuName 学生姓名
     * @param math 数学成绩
     * @param chinese 语文成绩
     */
    public Student(int stuNum,String stuName,float math,float chinese){
        this.setStuNum(stuNum);
        this.setStuName(stuName);
        this.setMath(math);
        this.setChinese(chinese);
    }

    public int getStuNum() {
        return stuNum;
    }

    public void setStuNum(int stuNum) {
        this.stuNum = stuNum;
    }

    public String getStuName() {
        return stuName;
    }

    public void setStuName(String stuName) {
        this.stuName = stuName;
    }

    public float getMath() {
        return math;
    }

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

    public float getChinese() {
        return chinese;
    }

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

    @Override
    public String toString() {
        return "学生信息{" +
                "学号" + stuNum +
                ",姓名='" + stuName + '\'' +
                ", 数学成绩=" + math +
                ", 语文成绩=" + chinese +
                '}';
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null || getClass() != obj.getClass()) return false;
        Student student = (Student) obj;
        return stuNum == student.stuNum && Float.compare(student.math, math) == 0 && Float.compare(student.chinese, chinese) == 0 && stuName.equals(student.stuName);
    }

    @Override
    public int hashCode() {
        return Objects.hash(stuNum, stuName, math, chinese);
    }
}





import java.util.Comparator;

public class YuWen implements Comparator<BanJi> {

    @Override
    public int compare(BanJi o1, BanJi o2) {
        int f=0;
        float b1=o1.yuwen();
        float b2=o2.yuwen();
        f=(int) (b2-b1);
        return f;
    }
}




import java.util.Comparator;

public class ShuXue implements Comparator<BanJi> {
    @Override
    public int compare(BanJi o1, BanJi o2) {
        int i=0;
        float b1=o1.shuxue();
        float b2= o2.shuxue();
        i=(int) (b2-b1);
        return i;
    }



}