IO (потоки ввода - вывода)

DeleteStudentException.java

public class DeleteStudentException extends Exception {
    
    @Override
    public String getMessage() {
        return "Этот студент уже изгнан из группы!";
    }
    
}

Group.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

/**
 *
 * @author kamaz
 */
public class Group implements Voenkomat {

    private Student[] array = new Student[10];

    public Group(Student[] array) {
        this.array = array;
    }

    public Group() {
        super();
    }

    public Student[] getArray() {
        return array;
    }

    public void setArray(Student[] array) {
        this.array = array;
    }
    
    public void writeGroup(File file) throws FileNotFoundException {
        StringBuffer bf = new StringBuffer();
        try (PrintWriter pw = new PrintWriter(file)) {
            for (int i = 0; i < array.length; i++) {
                bf.append(array[i].getName() + " " + array[i].getSurname() + " " + array[i].getSurnameTwo() + " " + array[i].getAge() + " " + array[i].isSex());
                bf.append(System.lineSeparator());
            }
            pw.print(bf);
            System.out.println("Writed");
        } catch (FileNotFoundException e) {
            System.out.println("File not found!!!");
        }
    }
    
    public void setStudents(Student st) {
        for (int i = 0; i < array.length; i++) {
            if (array[i] == null) {
                array[i] = st;
                return;
            }
        }
    }
    
    public Group returnGroup (File file) {
        Group b = new Group();
        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
        String str = " ";
            for (; (str = br.readLine()) != null;) {
                String[] arr = str.split(" ");
                String name = arr[0];
                String surname = arr[1];
                String surnameTwo = arr[2];
                int age = Integer.parseInt(arr[3]);
                boolean sex = Boolean.valueOf(arr[4]);
                    Student st = new Student(name, surname, surnameTwo, age, sex);
                    b.setStudents(st);
//        System.out.println(arr[2]);
//        System.out.println(st);
            }
        System.out.println();
        } catch (FileNotFoundException e) {
            System.out.println("File not found!");
        } catch (ArrayIndexOutOfBoundsException e) {
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("ERROR");
        }
//        System.out.println(Arrays.toString(array));
//        System.out.println(b);
        return b;
    }

    public void setStudent(Student st, int index) throws GroupException, GroupExceptionTwo {
        int indexTwo = 10;
        try {
            for (int i = 0; i < array.length; i++) {
                if ((i == index) && (array[i] == null)) {
                    array[i] = st;
                    System.out.println("Место студента " + st + " в группе: " + (i + 1));
                } else if ((i == index) && (array[i] != null)) {
                    throw new GroupExceptionTwo();
                } else if (indexTwo == index && (indexTwo++) == index) {
                    throw new GroupException();
                }
            }
        } catch (GroupExceptionTwo e) {
            System.out.println(e.getMessage());
        } catch (GroupException e) {
            System.out.println(e.getMessage());
        }
    }

    public void deleteStudent(int index) throws DeleteStudentException {
        try {
            for (int i = 0; i < array.length; i++) {
                if ((i == index) && (array[i] != null)) {
                    array[i] = null;
                    System.out.println("Студент с места: " + (i + 1) + " изгнан из группы");
                } else if ((i == index) && (array[i] == null)) {
                    throw new DeleteStudentException();
                }
            }
        } catch (DeleteStudentException e) {
            System.out.println(e.getMessage());
        }
    }

    public int countStudentInGroup() {
        int count = 0;
        for (int i = 0; i < array.length; i++) {
            if (array[i] != null) {
                count++;
            }
        }
        return count;
    }

    public String foundStudent(int index) {
        String n = null;
        for (int i = 0; i < array.length; i++) {
            if ((array[i] != null) && (i == index)) {
                n = array[i].getSurname();
            }
        }
        return n;
    }

    @Override
    public Student[] getVon() {
        Student[] stu = new Student[10];
        int j = 0;
        for (int i = 0; i < array.length; i++) {
            if (array[i] != null && array[i].getAge() >= 18 && array[i].isSex() == true) {
                stu[j] = array[i];
                j++;
            }
        }
        System.out.println(Arrays.toString(stu));
        return stu;
    }

    public void sortStudentsByParametrs() {
        Scanner sc = new Scanner(System.in);
        System.out.println("Выберите за каким параметром хотите отсортировать студентов (name, surname, surnameTwo, age, sex) ");
        String n = sc.nextLine();

        try {
            if (n.equals("name")) {
                for (int i = 0; i < array.length - 1; i++) {
                    for (int j = i + 1; j < array.length; j++) {
                        if (array[i] == null || array[j] == null) {
                            continue;
                        }
                        if (array[i].getName().compareTo(array[j].getName()) > 0) {
                            Student temp = array[i];
                            array[i] = array[j];
                            array[j] = temp;
                        }
                    }
                }
            } else if (n.equals("surname")) {
                for (int i = 0; i < array.length - 1; i++) {
                    for (int j = i + 1; j < array.length; j++) {
                        if (array[i] == null || array[j] == null) {
                            continue;
                        }
                        if (array[i].getSurname().compareTo(array[j].getSurname()) > 0) {
                            Student temp = array[i];
                            array[i] = array[j];
                            array[j] = temp;
                        }
                    }
                }
            } else if (n.equals("surnameTwo")) {
                for (int i = 0; i < array.length - 1; i++) {
                    for (int j = i + 1; j < array.length; j++) {
                        if (array[i] == null || array[j] == null) {
                            continue;
                        }
                        if (array[i].getSurnameTwo().compareTo(array[j].getSurnameTwo()) > 0) {
                            Student temp = array[i];
                            array[i] = array[j];
                            array[j] = temp;
                        }
                    }
                }
            } else if (n.equals("age")) {
                for (int i = 0; i < array.length - 1; i++) {
                    for (int j = i + 1; j < array.length; j++) {
                        if (array[i] == null || array[j] == null) {
                            continue;
                        }
                        if (array[i].getAge() > array[j].getAge()) {
                            Student temp = array[i];
                            array[i] = array[j];
                            array[j] = temp;
                        }
                    }
                }
            } else if (n.equals("sex")) {
                for (int i = 0; i < array.length - 1; i++) {
                    for (int j = i + 1; j < array.length; j++) {
                        if (array[i] == null || array[j] == null) {
                            continue;
                        }
                        if (array[j].isSex() == true) {
                            Student temp = array[i];
                            array[i] = array[j];
                            array[j] = temp;
                        }
                    }
                }
            } else {
                throw new NotCorrectParametrException();
            }
            System.out.println(Arrays.toString(array));

        } catch (NotCorrectParametrException e) {
            System.out.println(e.getMessage());
        }
    }

    public void setStudentOne(int index) throws GroupException, GroupExceptionTwo, Exception {
        int indexTwo = 10;
        try {
            Scanner sc = new Scanner(System.in);
            System.out.println("Введите name");
            String name = sc.nextLine();
            System.out.println("Введите surname");
            String surname = sc.nextLine();
            System.out.println("Введите surnameTwo");
            String surnameTwo = sc.nextLine();
            System.out.println("Введите age");
            int age = sc.nextInt();
            System.out.println("Введите sex");
            boolean sex = sc.nextBoolean();

            Student stud = new Student(name, surname, surnameTwo, age, sex);

            for (int i = 0; i < array.length; i++) {
                if (array[i] == null && i == index) {
                    array[i] = stud;
                    System.out.println("Студент: " + stud);
                    System.out.println(Arrays.toString(array));
                } else if (array[i] != null && i == index) {
                    throw new GroupExceptionTwo();
                } else if (array[i] == null || i == (indexTwo++) || i == indexTwo) {
                    throw new GroupException();
                }
            }
        } catch (GroupExceptionTwo e) {
            System.out.println(e.getMessage());
        } catch (GroupException e) {
            System.out.println(e.getMessage());
        } catch (Exception e) {
            System.out.println("Вы ввели не корректные параметры");
        }
    }

    @Override
    public String toString() {
        int j = 0;
        String[] arraySurname = new String[countStudentInGroup()];
        for (int i = 0; i < array.length; i++) {
            if (array[i] != null) {
                arraySurname[j] = array[i].getSurname();
                j++;
            }
        }
        Arrays.sort(arraySurname);
        return "Group: " + Arrays.toString(arraySurname);
        
    }

}

GroupException.java

public class GroupException extends Exception {
    
    @Override
    public String getMessage() {
        return "В этой группе больше студентов не может быть!";
    }
    
}

GroupExceptionTwo.java

public class GroupExceptionTwo extends Exception {
    
    @Override
    public String getMessage() {
        return "Это место в группе уже занято!";
    }
    
}

Human.java

public class Human {
    
    private String name;
    private String surname;
    private String surnameTwo;
    private int age;
    private boolean sex;

    public Human(String name, String surname, String surnameTwo, int age, boolean sex) {
        this.name = name;
        this.surname = surname;
        this.surnameTwo = surnameTwo;
        this.age = age;
        this.sex = sex;
    }
    
    public Human() {
        super();
    }

    public String getName() {
        return name;
    }

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

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
    }

    public String getSurnameTwo() {
        return surnameTwo;
    }

    public void setSurnameTwo(String surnameTwo) {
        this.surnameTwo = surnameTwo;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public boolean isSex() {
        return sex;
    }

    public void setSex(boolean sex) {
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "Student: " + name + ", " + surname + ", " + surnameTwo + ", " + age + ", " + sex + "; ";
    }
    
}

Main.java

import java.io.File;

/**
 *
 * @author kamaz
 */
public class Main {
    
    public static void main(String[] args) throws GroupException, GroupExceptionTwo, DeleteStudentException, NotCorrectParametrException, Exception {
        
        Student one = new Student("Ivan", "Petrov", "Vasilievich", 18, true);
        Student two = new Student("Anna", "Petrova", "Igorevna", 17, false);
        Student three = new Student("Olia", "Vetrova", "Pavlovna", 21, false);
        Student four = new Student("Igor", "Shvedenko", "Rostyslavovych", 19, true);
        Student five = new Student("Roman", "Kryvobok", "Valerievich", 15, true);
        Student six = new Student("Kostiantyn", "Khalyk", "Stepanovych", 31, true);
        Student seven = new Student("Tatyana", "Bigun", "Oleksandrovna", 26, false);
        Student eight = new Student("Anastasia", "Isachenko", "Valentinovna", 25, false);
        Student nine = new Student("Viacheslav", "Zhyzhula", "Olegovych", 14, true);
        Student ten = new Student("Kamila", "Tanchyk", "Kostiantynovna", 21, false);
        
        Student eleven = new Student("Misha", "Bogatyriov", "Ivanovych", 30, true);
        Student twelve = new Student("Oksana", "Fedorinenko", "Bogdanovna", 30, false);
        
        Group a = new Group();
        
        a.setStudent(one, 0);
        a.setStudent(two, 1);
        a.setStudent(three, 2);
        a.setStudent(four, 3);
        a.setStudent(five, 4);
        a.setStudent(six, 5);
        a.setStudent(seven, 6);
        a.setStudent(eight, 7);
        a.setStudent(nine, 8);
        a.setStudent(ten, 9);
//        a.setStudent(eleven, 10);
//        a.setStudent(twelve, 9);
        System.out.println("-------------");
//        System.out.println(a);
//        System.out.println("-------------");
//        
//        System.out.println(a.foundStudent(9));
//        System.out.println("-------------");
//
//        a.getVon();
//        a.deleteStudent(5);
////        a.deleteStudent(0);
////        a.deleteStudent(2);
////        a.deleteStudent(2);
////        System.out.println(a);
//        
//        System.out.println("-------------");
//        a.sortStudentsByParametrs();
//        
//        System.out.println("-------------");
//        a.setStudentOne(5);
//        
//        System.out.println("-------------");
//        a.getVon();
//        
//        System.out.println("-------------");
        File file = new File("group.txt");
        file.createNewFile();
        a.writeGroup(file);
        
        System.out.println("-------------");
        a.returnGroup(file);
    }
    
}

NotCorrectParametrException.java

public class NotCorrectParametrException extends Exception {
    
    @Override
    public String getMessage() {
        return "Вы ввели не корректный параметр сортировки!";
    }
    
}

Student.java

public class Student extends Human {

    public Student(String name, String surname, String surnameTwo, int age, boolean sex) {
        super(name, surname, surnameTwo, age, sex);
    }
    
    public Student() {
        super();
    }

    @Override
    public String toString() {
        return super.toString(); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void setSex(boolean sex) {
        super.setSex(sex); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public boolean isSex() {
        return super.isSex(); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void setAge(int age) {
        super.setAge(age); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public int getAge() {
        return super.getAge(); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void setSurnameTwo(String surnameTwo) {
        super.setSurnameTwo(surnameTwo); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public String getSurnameTwo() {
        return super.getSurnameTwo(); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void setSurname(String surname) {
        super.setSurname(surname); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public String getSurname() {
        return super.getSurname(); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void setName(String name) {
        super.setName(name); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public String getName() {
        return super.getName(); //To change body of generated methods, choose Tools | Templates.
    }
    
}

Voenkomat.java

public interface Voenkomat {
    
    public Student[] getVon();    

}