file_list[int(i / 0.007 - 1), 3 * j]

This code is accessing a specific element in a two-dimensional array called `file_list`.

The first index is calculated by dividing the value of `i` by 0.007 and then subtracting 1. This will give a decimal value, which will be rounded down to the nearest integer when used as an index.

The second index is calculated by multiplying `j` by 3. This is because the array has three columns, and we want to access the first column for the specified row.

Overall, this code is accessing a specific value in the first column of a row in the `file_list` array.

相关问题

创建Book类成员属性有书号，书名，作者，价格，出版社，出版年份创建该类的10个对象将这10个对象存入excel文件并读出到List集合中Java

非常感谢您的提问。

关于您的问题，我可以为您提供一些思路。

首先，我们需要创建一个Book类，其中包含一些成员属性，如书号、书名、作者、价格、出版社、出版年份。这可以通过以下代码实现：

public class Book {
    private String bookNo;
    private String bookName;
    private String author;
    private double price;
    private String publisher;
    private int publishYear;
    
    // 构造函数
    public Book(String bookNo, String bookName, String author,
                double price, String publisher, int publishYear) {
        this.bookNo = bookNo;
        this.bookName = bookName;
        this.author = author;
        this.price = price;
        this.publisher = publisher;
        this.publishYear = publishYear;
    }
    
    // getter 和 setter 方法
    // ...
}

然后，我们可以创建10个Book对象，存入一个List集合中。接着，我们需要将这些Book对象存入Excel文件中。这可以通过使用Apache POI和JXL等库来实现。

以下是一个示例代码，演示如何将10个Book对象存入Excel文件中，并在读取Excel文件后将这些Book对象读取到List集合中。

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class Main {
    public static void main(String[] args) throws IOException {
        // 创建10个Book对象
        List<Book> books = new ArrayList<>();
        books.add(new Book("001", "Java编程思想", "Bruce Eckel", 98.0,
                            "机械工业出版社", 2007));
        books.add(new Book("002", "深入浅出设计模式", "程杰", 59.0,
                            "电子工业出版社", 2010));
        books.add(new Book("003", "Head First 设计模式", "Freeman, Eric and Susa", 85.0,
                            "中国电力出版社", 2009));
        books.add(new Book("004", "Effective Java", "Joshua Bloch", 78.0,
                            "人民邮电出版社", 2008));
        books.add(new Book("005", "大话设计模式", "程杰", 46.0,
                            "人民邮电出版社", 2016));
        books.add(new Book("006", "算法导论", "Thomas H. Cormen", 88.0,
                            "机械工业出版社", 2013));
        books.add(new Book("007", "高性能MySQL", "Baron Schwartz", 103.0,
                            "人民邮电出版社", 2014));
        books.add(new Book("008", "Java并发编程实战", "Brian Goetz", 69.0,
                            "机械工业出版社", 2012));
        books.add(new Book("009", "编程珠玑", "Jon Bentley", 49.0,
                            "人民邮电出版社", 2007));
        books.add(new Book("010", "设计模式：可复用面向对象软件的基础", "Erich Gamma", 99.0,
                            "人民邮电出版社", 2007));
        
        // 将10个Book对象存入Excel文件中
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet("books");
        // 写入表头
        HSSFRow headerRow = sheet.createRow(0);
        headerRow.createCell(0).setCellValue("书号");
        headerRow.createCell(1).setCellValue("书名");
        headerRow.createCell(2).setCellValue("作者");
        headerRow.createCell(3).setCellValue("价格");
        headerRow.createCell(4).setCellValue("出版社");
        headerRow.createCell(5).setCellValue("出版年份");
        // 写入数据
        int rowIndex = 1;
        for (Book book : books) {
            HSSFRow row = sheet.createRow(rowIndex++);
            row.createCell(0).setCellValue(book.getBookNo());
            row.createCell(1).setCellValue(book.getBookName());
            row.createCell(2).setCellValue(book.getAuthor());
            row.createCell(3).setCellValue(book.getPrice());
            row.createCell(4).setCellValue(book.getPublisher());
            row.createCell(5).setCellValue(book.getPublishYear());
        }
        // 保存Excel文件
        File file = new File("books.xls");
        if (!file.exists()) {
            file.createNewFile();
        }
        FileOutputStream outputStream = new FileOutputStream(file);
        workbook.write(outputStream);
        outputStream.close();
        
        // 从Excel文件中读取Book对象到List集合中
        List<Book> bookList = new ArrayList<>();
        // ...
    }
}

上述代码中的写入Excel文件的部分使用了Apache POI库（版本为3.17）。如果您的开发环境中没有该库，请根据实际情况进行安装，并将相关类的导入语句添加到代码中。在读取Excel文件的部分，我们可以使用Apache POI、JXL或其他支持读取Excel文件的库。

在这里，我建议您使用Apache POI库来读取Excel文件中的数据。以下是一个读取Excel文件的示例代码：

import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class Main {
    public static void main(String[] args) throws IOException {
        // 从Excel文件中读取Book对象到List集合中
        List<Book> bookList = new ArrayList<>();
        FileInputStream inputFile = new FileInputStream("books.xls");
        HSSFWorkbook workbook = new HSSFWorkbook(inputFile);
        HSSFSheet sheet = workbook.getSheet("books");
        for (int rowIndex = 1; rowIndex <= sheet.getLastRowNum(); rowIndex++) {
            HSSFRow row = sheet.getRow(rowIndex);
            String bookNo = getStringCellValue(row.getCell(0));
            String bookName = getStringCellValue(row.getCell(1));
            String author = getStringCellValue(row.getCell(2));
            double price = getNumericCellValue(row.getCell(3));
            String publisher = getStringCellValue(row.getCell(4));
            int publishYear = (int) getNumericCellValue(row.getCell(5));
            bookList.add(new Book(bookNo, bookName, author, price, publisher, publishYear));
        }
        inputFile.close();
        // ...
    }
    
    private static String getStringCellValue(HSSFCell cell) {
        if (cell == null) {
            return "";
        }
        return cell.getStringCellValue().trim();
    }
    
    private static double getNumericCellValue(HSSFCell cell) {
        if (cell == null) {
            return 0.0;
        }
        return cell.getNumericCellValue();
    }
}

在这个示例代码中，我们使用了Apache POI库中的HSSFWorkbook、HSSFSheet、HSSFRow和HSSFCell类型来读取Excel文件中的数据。如果您在实际应用中使用的是JXL或其他库，可以相应地进行修改。

最后，我还需要说明一点：在实际开发中，我们通常不会在书写代码的过程中包含机密信息，例如密码、密钥等，以避免这些信息泄露。因此，在编写代码时请注意保护您的机密信息，不要暴露给任何人或程序。

编写java程序：创建有员工类，包括姓名、工号、性别、出生年月、家庭地址等。本系统能够按姓名或工号查找员工，并显示相关员工情况。包括：主控程序、员工档案管理子系统、员工类等。 其他要求： （1）实用，各模块自成系统 （2）完成最低要求：建立一个文件，包括同一个专业10个员工的必要信息，能对文件进行补充、修订、删除，并能进行查找。 （3）进一步要求：完成包括整个工厂所有员工的信息系统。

好的，以下是一个简单的 Java 程序，实现了上述要求：

Employee.java

public class Employee {
    private String name;
    private String id;
    private String gender;
    private String birthDate;
    private String address;

    public Employee(String name, String id, String gender, String birthDate, String address) {
        this.name = name;
        this.id = id;
        this.gender = gender;
        this.birthDate = birthDate;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public String getId() {
        return id;
    }

    public String getGender() {
        return gender;
    }

    public String getBirthDate() {
        return birthDate;
    }

    public String getAddress() {
        return address;
    }

    @Override
    public String toString() {
        return "Name: " + name + ", ID: " + id + ", Gender: " + gender +
                ", Birth Date: " + birthDate + ", Address: " + address;
    }
}

EmployeeManagementSystem.java

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

public class EmployeeManagementSystem {
    private List<Employee> employeeList = new ArrayList<>();
    private Scanner scanner = new Scanner(System.in);
    private File file = new File("employee.txt");

    public static void main(String[] args) {
        EmployeeManagementSystem ems = new EmployeeManagementSystem();
        ems.run();
    }

    private void run() {
        loadEmployeesFromFile();
        while (true) {
            System.out.println("Please select an option:");
            System.out.println("1. Add employee");
            System.out.println("2. View employee by name");
            System.out.println("3. View employee by ID");
            System.out.println("4. Update employee");
            System.out.println("5. Remove employee");
            System.out.println("6. Quit");
            int option = scanner.nextInt();
            scanner.nextLine();
            switch (option) {
                case 1:
                    addEmployee();
                    break;
                case 2:
                    searchEmployeeByName();
                    break;
                case 3:
                    searchEmployeeById();
                    break;
                case 4:
                    updateEmployee();
                    break;
                case 5:
                    removeEmployee();
                    break;
                case 6:
                    saveEmployeesToFile();
                    System.out.println("Bye!");
                    return;
                default:
                    System.out.println("Invalid option, please try again.");
            }
        }
    }

    private void addEmployee() {
        System.out.println("Please enter the employee's name:");
        String name = scanner.nextLine();

        System.out.println("Please enter the employee's ID:");
        String id = scanner.nextLine();

        System.out.println("Please enter the employee's gender:");
        String gender = scanner.nextLine();

        System.out.println("Please enter the employee's birth date:");
        String birthDate = scanner.nextLine();

        System.out.println("Please enter the employee's address:");
        String address = scanner.nextLine();

        Employee employee = new Employee(name, id, gender, birthDate, address);
        employeeList.add(employee);
        System.out.println("Employee added successfully.");
    }

    private void searchEmployeeByName() {
        System.out.println("Please enter the employee's name:");
        String name = scanner.nextLine();

        for (Employee employee : employeeList) {
            if (employee.getName().equals(name)) {
                System.out.println(employee);
                return;
            }
        }

        System.out.println("Employee not found.");
    }

    private void searchEmployeeById() {
        System.out.println("Please enter the employee's ID:");
        String id = scanner.nextLine();

        for (Employee employee : employeeList) {
            if (employee.getId().equals(id)) {
                System.out.println(employee);
                return;
            }
        }

        System.out.println("Employee not found.");
    }

    private void updateEmployee() {
        System.out.println("Please enter the employee's ID:");
        String id = scanner.nextLine();

        for (Employee employee : employeeList) {
            if (employee.getId().equals(id)) {
                System.out.println("Please enter the employee's name:");
                employee.name = scanner.nextLine();

                System.out.println("Please enter the employee's ID:");
                employee.id = scanner.nextLine();

                System.out.println("Please enter the employee's gender:");
                employee.gender = scanner.nextLine();

                System.out.println("Please enter the employee's birth date:");
                employee.birthDate = scanner.nextLine();

                System.out.println("Please enter the employee's address:");
                employee.address = scanner.nextLine();

                System.out.println("Employee updated successfully.");
                return;
            }
        }

        System.out.println("Employee not found.");
    }

    private void removeEmployee() {
        System.out.println("Please enter the employee's ID:");
        String id = scanner.nextLine();

        for (Employee employee : employeeList) {
            if (employee.getId().equals(id)) {
                employeeList.remove(employee);
                System.out.println("Employee removed successfully.");
                return;
            }
        }

        System.out.println("Employee not found.");
    }

    private void loadEmployeesFromFile() {
        try (Scanner fileScanner = new Scanner(file)) {
            while (fileScanner.hasNextLine()) {
                String[] employeeData = fileScanner.nextLine().split(",");
                Employee employee = new Employee(
                        employeeData[0],
                        employeeData[1],
                        employeeData[2],
                        employeeData[3],
                        employeeData[4]
                );
                employeeList.add(employee);
            }
            System.out.println("Employees loaded successfully.");
        } catch (FileNotFoundException e) {
            System.out.println("File not found: " + file.getAbsolutePath());
        }
    }

    private void saveEmployeesToFile() {
        try (PrintWriter writer = new PrintWriter(file)) {
            for (Employee employee : employeeList) {
                writer.println(
                        employee.getName() + "," +
                        employee.getId() + "," +
                        employee.getGender() + "," +
                        employee.getBirthDate() + "," +
                        employee.getAddress()
                );
            }
            System.out.println("Employees saved successfully.");
        } catch (FileNotFoundException e) {
            System.out.println("File not found: " + file.getAbsolutePath());
        }
    }
}

该程序使用了一个 Employee 类来表示员工，包含了姓名、工号、性别、出生年月、家庭地址等属性。然后实现了一个 EmployeeManagementSystem 类，用于管理员工信息。主要包括添加员工、查找员工、修改员工、删除员工等功能，并且能将员工信息保存到文件中。

你可以在文件中输入以下内容来进行测试：

Alice,A001,Female,1990-01-01,123 Main St
Bob,B002,Male,1995-06-15,456 Second St
Charlie,C003,Male,1985-09-30,789 Third St
David,D004,Male,1998-12-25,123 Fourth St
Eve,E005,Female,1992-03-10,456 Fifth St
Frank,F006,Male,1991-07-01,789 Sixth St
Grace,G007,Female,1989-10-20,123 Seventh St
Harry,H008,Male,1987-05-05,456 Eighth St
Ivy,I009,Female,1994-08-31,789 Ninth St
John,J010,Male,1986-04-16,123 Tenth St

希望这个程序能够帮助你完成员工信息管理系统的开发。如果你有任何问题或需要更多的帮助，请随时与我联系。