使用list集合模拟学员数据库 先进行学员信息初试化 包括功能1.添加学员功能 2.查询全部学员 3.根据学员编号查询 4.根据学员班级名查询 5.根据学员状态查询 6.退出系统java完整代码

在Java中，可以使用`ArrayList`集合来模拟学员数据库，其中每个学员的信息可以通过一个自定义的类（例如`Student`类）来表示。以下是一个简单的示例代码，实现了您要求的功能：

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

class Student {
    private String id;
    private String name;
    private String classId;
    private String status;

    public Student(String id, String name, String classId, String status) {
        this.id = id;
        this.name = name;
        this.classId = classId;
        this.status = status;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getClassId() {
        return classId;
    }

    public String getStatus() {
        return status;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", classId='" + classId + '\'' +
                ", status='" + status + '\'' +
                '}';
    }
}

public class StudentDatabaseSimulator {
    private static List<Student> studentList = new ArrayList<>();
    private static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        initializeDatabase();
        int choice;
        do {
            System.out.println("1. 添加学员");
            System.out.println("2. 查询全部学员");
            System.out.println("3. 根据学员编号查询");
            System.out.println("4. 根据学员班级名查询");
            System.out.println("5. 根据学员状态查询");
            System.out.println("6. 退出系统");
            System.out.print("请选择操作：");
            choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addStudent();
                    break;
                case 2:
                    queryAllStudents();
                    break;
                case 3:
                    queryStudentById();
                    break;
                case 4:
                    queryStudentsByClassId();
                    break;
                case 5:
                    queryStudentsByStatus();
                    break;
                case 6:
                    System.out.println("退出系统");
                    break;
                default:
                    System.out.println("无效的操作，请重新选择。");
            }
        } while (choice != 6);
    }

    private static void initializeDatabase() {
        studentList.add(new Student("001", "张三", "1班", "在校"));
        studentList.add(new Student("002", "李四", "2班", "毕业"));
        studentList.add(new Student("003", "王五", "1班", "在校"));
        // 可以添加更多的学员信息
    }

    private static void addStudent() {
        System.out.print("请输入学员编号：");
        String id = scanner.next();
        System.out.print("请输入学员姓名：");
        String name = scanner.next();
        System.out.print("请输入学员班级名：");
        String classId = scanner.next();
        System.out.print("请输入学员状态：");
        String status = scanner.next();
        studentList.add(new Student(id, name, classId, status));
        System.out.println("添加成功！");
    }

    private static void queryAllStudents() {
        for (Student student : studentList) {
            System.out.println(student);
        }
    }

    private static void queryStudentById() {
        System.out.print("请输入学员编号：");
        String id = scanner.next();
        for (Student student : studentList) {
            if (student.getId().equals(id)) {
                System.out.println(student);
                return;
            }
        }
        System.out.println("未找到该学员！");
    }

    private static void queryStudentsByClassId() {
        System.out.print("请输入学员班级名：");
        String classId = scanner.next();
        for (Student student : studentList) {
            if (student.getClassId().equals(classId)) {
                System.out.println(student);
            }
        }
    }

    private static void queryStudentsByStatus() {
        System.out.print("请输入学员状态：");
        String status = scanner.next();
        for (Student student : studentList) {
            if (student.getStatus().equals(status)) {
                System.out.println(student);
            }
        }
    }
}

这段代码定义了一个`Student`类来存储学员信息，并使用`StudentDatabaseSimulator`类中的`studentList`来模拟数据库存储所有学员对象。程序提供了添加学员、查询全部学员、根据学员编号查询、根据学员班级名查询、根据学员状态查询以及退出系统的功能。