java在集合,ArrayList集合完成,咋写

public class Test {
public static void main(String[] args) {

    ## 定义一个ArrayList集合，保存学生的对象。
    ## 快速实例化5个学生对象，依次存入集合中。
      ##  将集合中的对象进行排序，三门课程的总分最高分在前面，总分最低分在后面。
      ##  请实现，并输出集合数据验证。
      ##  算出语文的平均分输出。
       ## 语文分数低于平均分的学生信息输出。(对象里面的输出方法)
      ## 数学最高分的学生信息输出。
     

    ArrayList<Student> list=new ArrayList<Students>();
    Student s1=new Students("张三",81,72,99);
    Student s2=new Students("李四",82,72,55);
    Student s3=new Students("王五",83,73,46);
    Student s4=new Students("赵六",84,77,86);
    Student s5=new Students("田七",85,79,77);
    list.add(s1);
    list.add(s2);
    list.add(s3);
    list.add(s4);
    list.add(s5);
    Iterator<Students> iterator=list.iterator();
    while (iterator.hasNext()){
        System.out.println(iterator.next().PrintStu());
    }
    Collections.sort(list, new Comparator<Students>() {
        @Override
        public int compare(Students o1, Students o2) {
            int num1=o1.getYwscore()+o1.getYyscore()+o1.getYyscore();
            int num2=o2.getYwscore()+o2.getYyscore()+o2.getYyscore();
            if (num1>num2){
                return -1;
            }if (num1==num2){
                return 0;
            }
            return 1;
        }
    });
    System.out.println(list);
}

public class Student {

String name;
 int ywscore;
 int yyscore;
int sxscore;

public Students(){}
public Students(String name, int ywscore, int yyscore, int sxscore) {
    this.name = name;
    this.ywscore = ywscore;
    this.yyscore = yyscore;
    this.sxscore = sxscore;
}
public boolean PrintStu(){
    System.out.println("姓名："+name+":语文成绩："+ywscore+",英语成绩"+yyscore+",数学成绩："+sxscore);
    return false;
}
public void setName(String name) {
    this.name = name;
}

public void setYwscore(int ywscore) {
    this.ywscore = ywscore;
}

public void setYyscore(int yyscore) {
    this.yyscore = yyscore;
}

public void setSxscore(int sxscore) {
    this.sxscore = sxscore;
}

public String getName() {
    return name;
}

public int getYwscore() {
    return ywscore;
}

public int getYyscore() {
    return yyscore;
}

public int getSxscore() {
    return sxscore;
}

}

public class Student {
    String name;
    int ywscore;
    int yyscore;
    int sxscore;

    public Student() {
    }

    public Student(String name, int ywscore, int yyscore, int sxscore) {
        this.name = name;
        this.ywscore = ywscore;
        this.yyscore = yyscore;
        this.sxscore = sxscore;
    }

    public boolean PrintStu() {
        System.out.println("姓名：" + name + ":语文成绩：" + ywscore + ",英语成绩" + yyscore + ",数学成绩：" + sxscore);
        return false;
    }

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

    public void setYwscore(int ywscore) {
        this.ywscore = ywscore;
    }

    public void setYyscore(int yyscore) {
        this.yyscore = yyscore;
    }

    public void setSxscore(int sxscore) {
        this.sxscore = sxscore;
    }

    public String getName() {
        return name;
    }

    public int getYwscore() {
        return ywscore;
    }

    public int getYyscore() {
        return yyscore;
    }

    public int getSxscore() {
        return sxscore;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", ywscore=" + ywscore +
                ", yyscore=" + yyscore +
                ", sxscore=" + sxscore +
                '}';
    }

    public static void main(String[] args) {
        ArrayList<Student> list = new ArrayList<Student>();
        Student s1 = new Student("张三", 81, 72, 99);
        Student s2 = new Student("李四", 82, 72, 55);
        Student s3 = new Student("王五", 83, 73, 46);
        Student s4 = new Student("赵六", 84, 77, 86);
        Student s5 = new Student("田七", 85, 79, 77);
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s4);
        list.add(s5);

        // 将集合中的对象进行排序，三门课程的总分最高分在前面，总分最低分在后面。
        orderBySum(list);

        // 请实现，并输出集合数据验证。
        System.out.println("成绩从高到低：" + list);

        // 算出语文的平均分输出。
        double sum = 0;
        for (Student student : list) {
            sum += student.getYwscore();
        }
        double avg = sum / list.size();
        System.out.println("语文平均分：" + avg);

        // 语文分数低于平均分的学生信息输出。(对象里面的输出方法)
        for (Student student : list) {
            if (student.getYwscore() < avg) {
                System.out.println("语文分数低于平均分的学生信息：" + student);
            }
        }

        // 数学最高分的学生信息输出。
        int max = 0;
        int index = 0;
        for (int i = 0; i < list.size(); i++) {
            Student student = list.get(i);
            if (student.getSxscore() > max) {
                max = student.getSxscore();
                index = i;
            }
        }
        System.out.println("数学最高分的学生信息：" + list.get(index));
    }

    private static void orderBySum(ArrayList<Student> list) {
        Collections.sort(list, new Comparator<Student>() {
            @Override
            public int compare(Student o1, Student o2) {
                int num1 = o1.getSxscore() + o1.getYwscore() + o1.getYyscore();
                int num2 = o2.getSxscore() + o2.getYwscore() + o2.getYyscore();
                return num2 - num1;
            }
        });
    }
}

Collections.sort(list, new Comparator<Students>() {
        @Override
        public int compare(Students o1, Students o2) {
            int num1=o1.getYwscore()+o1.getYyscore()+o1.getYyscore();
            int num2=o2.getYwscore()+o2.getYyscore()+o2.getYyscore();
            return num2 - num1;
        }
    });

num1-num2是升序，num2-num1是降序

使用这种方式就可实现各种排序，当然可以Student实现Comparable，两种方式，根据不同的情况，喜好使用，Comparable具体用法自己查一下