下面这步怎么搞，帮看一下怎么弄

public class teststudent {
public static void main(string[] args){
Student student=new teststudent();
system.out.print('学号:'+student.getsno());//输出姓名
system.out.print('姓名:'+student.getsname());//输出姓名
system.out.print('性别:'+student.getssex());//输出性别
system.out.print('年龄:'+student.getsage());//输出年龄
system.out.print('成绩:'+student.getsjava());//输出成绩
}

}

public static void main(String[] args) {
        Student student=new Student("123","张三","男",20,81);
        System.out.println("学号:"+student.getSno());//输出姓名
        System.out.println("姓名:"+student.getSname());//输出姓名
        System.out.println("性别:"+student.getSsex());//输出性别
        System.out.println("年龄:"+student.getSage());//输出年龄
        System.out.println("成绩:"+student.getSjava());//输出成绩
        Student student1=new Student("123","张三1","男",20,80);
        Student student2=new Student("123","张三2","男",20,60);
        Student student3=new Student("123","张三3","男",20,96);
        Student student4=new Student("123","张三4","男",20,76);
        List<Student> scoreList = new ArrayList<Student>();
        scoreList.add(student);
        scoreList.add(student1);
        scoreList.add(student2);
        scoreList.add(student3);
        scoreList.add(student4);
        Integer max = scoreList.stream().max(Comparator.comparing(Student::getSjava)).get().getSjava();
        Integer min = scoreList.stream().min(Comparator.comparing(Student::getSjava)).get().getSjava();
        Double avg = scoreList.stream().collect(Collectors.averagingInt(Student::getSjava));
        System.out.println("最大值："+max);
        System.out.println("最小值："+min);
        System.out.println("平均值："+avg);
    }

public class Student {
    
    private String sno;
    private String sname;
    private String ssex;
    private Integer sage;
    private Integer sjava;
    
    public Student(String sno, String sname, String ssex, Integer sage, Integer sjava) {
        this.sno = sno;
        this.sname = sname;
        this.ssex = ssex;
        this.sage = sage;
        this.sjava = sjava;
    }
    public String getSno() {
        return sno;
    }
    public void setSno(String sno) {
        this.sno = sno;
    }
    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public String getSsex() {
        return ssex;
    }
    public void setSsex(String ssex) {
        this.ssex = ssex;
    }
    public Integer getSage() {
        return sage;
    }
    public void setSage(Integer sage) {
        this.sage = sage;
    }
    public Integer getSjava() {
        return sjava;
    }
    public void setSjava(Integer sjava) {
        this.sjava = sjava;
    }
    
}

import java.util.*;
class Main{
    static class Student {
        private String sno;
        private String sname;
        private String ssex;
        private int sage;
        private float sjava;

        public Student(String sno, String sname, String ssex, int sage, float sjava) {
            this.sno = sno;
            this.sname = sname;
            this.ssex = ssex;
            this.sage = sage;
            this.sjava = sjava;
        }

        public String getSno() {
            return sno;
        }

        public void setSno(String sno) {
            this.sno = sno;
        }

        public String getSname() {
            return sname;
        }

        public void setSname(String sname) {
            this.sname = sname;
        }

        public String getSsex() {
            return ssex;
        }

        public void setSsex(String ssex) {
            this.ssex = ssex;
        }

        public int getSage() {
            return sage;
        }

        public void setSage(int sage) {
            this.sage = sage;
        }

        public float getSjava() {
            return sjava;
        }

        public void setSjava(float sjava) {
            this.sjava = sjava;
        }
    }
    public static void main(String[] args) {
        List<Student> students = new ArrayList<>();
        Student s1 = new Student("001", "zhangsan", "nan", 18, 90.0f);
        students.add(s1);
        Student s2 = new Student("002", "liguifen", "nv", 17, 88.0f);
        students.add(s2);
        Student s3 = new Student("003", "wagnerxiao", "nan", 90, 67.0f);
        students.add(s3);
        Student s4 = new Student("004", "ergouzi", "nv", 23, 99.0f);
        students.add(s4);
        Student s5 = new Student("005", "lvdan", "nan", 25, 97.0f);
        students.add(s5);
        float average = 0.0f;
        float total = 0.0f;
        float max = s1.getSjava();
        float min = s1.getSjava();
        for(Student s : students) {
            total+=s.getSjava();
            System.out.print(s.getSno() + " " + s.getSname() + " " + s.getSsex() + " " + s.getSage() + " " + s.getSjava() + "\n");
            if(max < s.getSjava()) {
                max = s.getSjava();
            }
            
            if(min > s.getSjava()) {
                min = s.getSjava();
            }
        }
        System.out.println("average=" + total / students.size());
        System.out.println("max=" + max);
        System.out.println("min=" + min);
    }
}