一、人事管理系统要求在用户界面中输入一个员工的工号，姓名，年龄，工资，绩效，保存在一个本地文本文档中。可以对一个或所有员工的工号，年龄，工资，绩效显示在界面上。可以对所有员工的（工资+绩效）的总数进行排序显示在界面上。用java实现

好的，下面是一个简单的 Java 实现，包含了员工类和人事管理系统类：

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

class Employee {
    private int id;
    private String name;
    private int age;
    private double salary;
    private double performance;

    public Employee(int id, String name, int age, double salary, double performance) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.salary = salary;
        this.performance = performance;
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public double getSalary() {
        return salary;
    }

    public double getPerformance() {
        return performance;
    }

    public void setId(int id) {
        this.id = id;
    }

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

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

    public void setSalary(double salary) {
        this.salary = salary;
    }

    public void setPerformance(double performance) {
        this.performance = performance;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", salary=" + salary +
                ", performance=" + performance +
                '}';
    }
}

class EmployeeSystem {
    private ArrayList<Employee> employees;

    public EmployeeSystem() {
        employees = new ArrayList<>();
    }

    public void addEmployee(Employee employee) {
        employees.add(employee);
        saveToFile();
    }

    public void showAllEmployees() {
        for (Employee employee : employees) {
            System.out.println(employee);
        }
    }

    public void showEmployee(int id) {
        for (Employee employee : employees) {
            if (employee.getId() == id) {
                System.out.println(employee);
                return;
            }
        }
        System.out.println("Employee with ID " + id + " not found.");
    }

    public void showEmployeeStats() {
        double total = 0;
        for (Employee employee : employees) {
            total += employee.getSalary() + employee.getPerformance();
        }
        System.out.println("Total salary and performance: " + total);

        Collections.sort(employees, new Comparator<Employee>() {
            @Override
            public int compare(Employee o1, Employee o2) {
                return Double.compare(o2.getSalary() + o2.getPerformance(), o1.getSalary() + o1.getPerformance());
            }
        });

        System.out.println("Employees sorted by salary and performance:");
        for (Employee employee : employees) {
            System.out.println(employee);
        }
    }

    private void saveToFile() {
        try {
            FileWriter writer = new FileWriter("employees.txt");
            for (Employee employee : employees) {
                writer.write(String.format("%d,%s,%d,%.2f,%.2f\n", employee.getId(), employee.getName(), employee.getAge(), employee.getSalary(), employee.getPerformance()));
            }
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void loadFromFile() {
        try {
            File file = new File("employees.txt");
            Scanner scanner = new Scanner(file);
            while (scanner.hasNextLine()) {
                String[] parts = scanner.nextLine().split(",");
                int id = Integer.parseInt(parts[0]);
                String name = parts[1];
                int age = Integer.parseInt(parts[2]);
                double salary = Double.parseDouble(parts[3]);
                double performance = Double.parseDouble(parts[4]);
                employees.add(new Employee(id, name, age, salary, performance));
            }
            scanner.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

public class Main {
    public static void main(String[] args) {
        EmployeeSystem employeeSystem = new EmployeeSystem();
        employeeSystem.loadFromFile();

        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("1. Add employee");
            System.out.println("2. Show all employees");
            System.out.println("3. Show employee by ID");
            System.out.println("4. Show employee statistics");
            System.out.println("0. Exit");
            int choice = scanner.nextInt();
            scanner.nextLine();
            switch (choice) {
                case 1:
                    System.out.println("Enter employee ID:");
                    int id = scanner.nextInt();
                    scanner.nextLine();
                    System.out.println("Enter employee name:");
                    String name = scanner.nextLine();
                    System.out.println("Enter employee age:");
                    int age = scanner.nextInt();
                    scanner.nextLine();
                    System.out.println("Enter employee salary:");
                    double salary = scanner.nextDouble();
                    scanner.nextLine();
                    System.out.println("Enter employee performance score:");
                    double performance = scanner.nextDouble();
                    scanner.nextLine();
                    employeeSystem.addEmployee(new Employee(id, name, age, salary, performance));
                    break;
                case 2:
                    employeeSystem.showAllEmployees();
                    break;
                case 3:
                    System.out.println("Enter employee ID:");
                    int id2 = scanner.nextInt();
                    scanner.nextLine();
                    employeeSystem.showEmployee(id2);
                    break;
                case 4:
                    employeeSystem.showEmployeeStats();
                    break;
                case 0:
                    return;
            }
        }
    }
}

这个程序将员工信息保存在名为 `employees.txt` 的文本文件中，可以在下次运行程序时重新加载。在程序运行时，用户可以选择添加员工、显示所有员工、按 ID 显示员工、显示员工统计信息或退出程序。