java数据导出到excel

要将Java数据导出到Excel，可以使用Apache POI库。以下是一个示例代码：

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
 
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.DataFormat;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 
public class ExcelExporter {
 
    public static void main(String[] args) throws IOException {
 
        // 创建一个工作簿
        Workbook workbook = new XSSFWorkbook();
 
        // 创建一个工作表
        Sheet sheet = workbook.createSheet("Employee Data");
 
        // 设置日期格式
        CellStyle dateStyle = workbook.createCellStyle();
        DataFormat dateFormat = workbook.createDataFormat();
        dateStyle.setDataFormat(dateFormat.getFormat("yyyy/mm/dd"));
 
        // 创建表头行
        Row headerRow = sheet.createRow(0);
        headerRow.createCell(0).setCellValue("ID");
        headerRow.createCell(1).setCellValue("Name");
        headerRow.createCell(2).setCellValue("Role");
        headerRow.createCell(3).setCellValue("Salary");
        headerRow.createCell(4).setCellValue("Joining Date");
 
        // 填充数据行
        List<Employee> employees = getEmployeeData();
        int rowNum = 1;
        for (Employee employee : employees) {
            Row row = sheet.createRow(rowNum++);
            row.createCell(0).setCellValue(employee.getId());
            row.createCell(1).setCellValue(employee.getName());
            row.createCell(2).setCellValue(employee.getRole());
            row.createCell(3).setCellValue(employee.getSalary());
            row.createCell(4).setCellValue(employee.getJoiningDate());
            row.getCell(4).setCellStyle(dateStyle);
        }
 
        // 自动调整列宽
        for (int i = 0; i < headerRow.getLastCellNum(); i++) {
            sheet.autoSizeColumn(i);
        }
 
        // 设置文件名并写入文件
        String fileName = "employee_data.xlsx";
        FileOutputStream outputStream = new FileOutputStream(fileName);
        workbook.write(outputStream);
        workbook.close();
        outputStream.close();
 
        System.out.println("Excel file created successfully.");
    }
 
    // 生成示例数据
    private static List<Employee> getEmployeeData() {
        List<Employee> employees = new ArrayList<>();
        employees.add(new Employee(101, "John Doe", "Manager", 50000, new Date()));
        employees.add(new Employee(102, "Jane Doe", "Developer", 40000, new Date()));
        employees.add(new Employee(103, "Bob Smith", "Developer", 40000, new Date()));
        employees.add(new Employee(104, "Mary Smith", "Tester", 30000, new Date()));
        return employees;
    }
}
 
class Employee {
    private int id;
    private String name;
    private String role;
    private int salary;
    private Date joiningDate;
 
    public Employee(int id, String name, String role, int salary, Date joiningDate) {
        this.id = id;
        this.name = name;
        this.role = role;
        this.salary = salary;
        this.joiningDate = joiningDate;
    }
 
    public int getId() {
        return id;
    }
 
    public String getName() {
        return name;
    }
 
    public String getRole() {
        return role;
    }
 
    public int getSalary() {
        return salary;
    }
 
    public Date getJoiningDate() {
        return joiningDate;
    }
}

这个示例代码创建了一个包含员工数据的Excel文件。您可以根据自己的需求修改代码来导出自己的数据。