将二十个人按五人一组分组并使用student类编写Java程序

好的，让我理解一下你的问题。您需要编写一个Java程序，将二十个人分成五组，每组包含五个人，并使用student类编写。是吗？

如果是的话，以下是这样一个Java程序的示例代码：

public class Student {
    private String name;
    private int age;
    private String group;

    public Student(String name, int age, String group) {
        this.name = name;
        this.age = age;
        this.group = group;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getGroup() {
        return group;
    }

    public void setGroup(String group) {
        this.group = group;
    }
}

public class Grouping {
    public static void main(String[] args) {
        Student[] students = new Student[20];
        students[0] = new Student("John", 20, "");
        students[1] = new Student("Mary", 19, "");
        students[2] = new Student("David", 21, "");
        students[3] = new Student("Alice", 18, "");
        students[4] = new Student("Bob", 22, "");
        students[5] = new Student("Jack", 20, "");
        students[6] = new Student("Lucy", 19, "");
        students[7] = new Student("Peter", 21, "");
        students[8] = new Student("Sara", 18, "");
        students[9] = new Student("Tom", 22, "");
        students[10] = new Student("Eva", 20, "");
        students[11] = new Student("Mike", 19, "");
        students[12] = new Student("Maggie", 21, "");
        students[13] = new Student("Jim", 18, "");
        students[14] = new Student("Linda", 22, "");
        students[15] = new Student("Tim", 20, "");
        students[16] = new Student("Kate", 19, "");
        students[17] = new Student("Frank", 21, "");
        students[18] = new Student("Cathy", 18, "");
        students[19] = new Student("Joe", 22, "");

        Random random = new Random();
        List<Integer> list = new ArrayList<>(20);
        for (int i = 0; i < 20; i++) {
            list.add(i);
        }
        Collections.shuffle(list);

        for (int i = 0; i < 5; i++) {
            System.out.println("Group " + (i + 1));
            for (int j = 0; j < 5; j++) {
                int index = list.get(i * 5 + j);
                students[index].setGroup("Group " + (i + 1));
                System.out.println(students[index].getName());
            }
            System.out.println();
        }
     }
}

在这个程序中，我们首先定义了一个student类来表示每个学生。然后，我们创建了一个包含20个学生的数组，并将每个学生的信息填充到数组中。

接下来，我们使用一个Random对象，将0到19的整数放入一个ArrayList中。然后，使用Collections.shuffle()方法打乱ArrayList中的元素，保证每次执行程序时，分组都是随机的。

最后，我们使用两个嵌套的for循环，将20个学生分为5组，并打印出每个组中的学生名称。

希望这个程序能够对您有所帮助！