Java利用POI实现导入导出Excel表格示例代码

介绍

Jakarta POI 是一套用于访问微软格式文档的Java API。Jakarta POI有很多组件组成，其中有用于操作Excel格式文件的HSSF和用于操作Word的HWPF，在各种组件中目前只有用于操作Excel的HSSF相对成熟。官方主页http://poi.apache.org/index.html，API文档http://poi.apache.org/apidocs/index.html

实现

已经在代码中加入了完整的注释。

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

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

public class ExcelOperate {

  public static void main(String[] args) {
    // 创建Excel表格
    createExcel(getStudent());

    // 读取Excel表格
    List<Student> list = readExcel();
    System.out.println(list.toString());
  }

  /**
   * 初始化数据
   *
   * @return 数据
   */
  private static List<Student> getStudent() {
    List<Student> list = new ArrayList<Student>();
    Student student1 = new Student("小明", 8, "二年级");
    Student student2 = new Student("小光", 9, "三年级");
    Student student3 = new Student("小花", 10, "四年级");
    list.add(student1);
    list.add(student2);
    list.add(student3);
    return list;
  }

  /**
   * 创建Excel
   *
   * @param list
   *      数据
   */
  private static void createExcel(List<Student> list) {
    // 创建一个Excel文件
    HSSFWorkbook workbook = new HSSFWorkbook();
    // 创建一个工作表
    HSSFSheet sheet = workbook.createSheet("学生表一");
    // 添加表头行
    HSSFRow hssfRow = sheet.createRow(0);
    // 设置单元格格式居中
    HSSFCellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);

    // 添加表头内容
    HSSFCell headCell = hssfRow.createCell(0);
    headCell.setCellValue("姓名");
    headCell.setCellStyle(cellStyle);

    headCell = hssfRow.createCell(1);
    headCell.setCellValue("年龄");
    headCell.setCellStyle(cellStyle);

    headCell = hssfRow.createCell(2);
    headCell.setCellValue("年级");
    headCell.setCellStyle(cellStyle);

    // 添加数据内容
    for (int i = 0; i < list.size(); i++) {
      hssfRow = sheet.createRow((int) i + 1);
      Student student = list.get(i);

      // 创建单元格，并设置值
      HSSFCell cell = hssfRow.createCell(0);
      cell.setCellValue(student.getName());
      cell.setCellStyle(cellStyle);

      cell = hssfRow.createCell(1);
      cell.setCellValue(student.getAge());
      cell.setCellStyle(cellStyle);

      cell = hssfRow.createCell(2);
      cell.setCellValue(student.getGrade());
      cell.setCellStyle(cellStyle);
    }

    // 保存Excel文件
    try {
      OutputStream outputStream = new FileOutputStream("D:/students.xls");
      workbook.write(outputStream);
      outputStream.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  /**
   * 读取Excel
   *
   * @return 数据集合
   */
  private static List<Student> readExcel() {
    List<Student> list = new ArrayList<Student>();
    HSSFWorkbook workbook = null;

    try {
      // 读取Excel文件
      InputStream inputStream = new FileInputStream("D:/students.xls");
      workbook = new HSSFWorkbook(inputStream);
      inputStream.close();
    } catch (Exception e) {
      e.printStackTrace();
    }

    // 循环工作表
    for (int numSheet = 0; numSheet < workbook.getNumberOfSheets(); numSheet++) {
      HSSFSheet hssfSheet = workbook.getSheetAt(numSheet);
      if (hssfSheet == null) {
        continue;
      }
      // 循环行
      for (int rowNum = 1; rowNum <= hssfSheet.getLastRowNum(); rowNum++) {
        HSSFRow hssfRow = hssfSheet.getRow(rowNum);
        if (hssfRow == null) {
          continue;
        }

        // 将单元格中的内容存入集合
        Student student = new Student();

        HSSFCell cell = hssfRow.getCell(0);
        if (cell == null) {
          continue;
        }
        student.setName(cell.getStringCellValue());

        cell = hssfRow.getCell(1);
        if (cell == null) {
          continue;
        }
        student.setAge((int) cell.getNumericCellValue());

        cell = hssfRow.getCell(2);
        if (cell == null) {
          continue;
        }
        student.setGrade(cell.getStringCellValue());

        list.add(student);
      }
    }
    return list;
  }
}

附上Student类的代码

public class Student {

  private String name;
  private int age;
  private String grade;

  public Student() {
  }

  public Student(String name, int age, String grade) {
    super();
    this.name = name;
    this.age = age;
    this.grade = grade;
  }

  public String getName() {
    return name;
  }

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

  public int getAge() {
    return age;
  }

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

  public String getGrade() {
    return grade;
  }

  public void setGrade(String grade) {
    this.grade = grade;
  }

  @Override
  public String toString() {
    return "Student [name=" + name + ", age=" + age + ", grade=" + grade
        + "]";
  }
}

测试结果

导出的Excel表格

students

打印读取的Excel数据

[Student [name=小明, age=8, grade=二年级], Student [name=小光, age=9, grade=三年级], Student [name=小花, age=10, grade=四年级]]

总结

以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作能带来一定的帮助，如果有疑问大家可以留言交流。