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) {
    // 創(chuàng)建Excel表格
    createExcel(getStudent());

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

  /**
   * 初始化數(shù)據(jù)
   * 
   * @return 數(shù)據(jù)
   */
  private static List<Student> getStudent() {
    List<Student> list = new ArrayList<Student>();
    Student student1 = new Student("小明", 8, "二年級(jí)");
    Student student2 = new Student("小光", 9, "三年級(jí)");
    Student student3 = new Student("小花", 10, "四年級(jí)");
    list.add(student1);
    list.add(student2);
    list.add(student3);
    return list;
  }

  /**
   * 創(chuàng)建Excel
   * 
   * @param list
   *      數(shù)據(jù)
   */
  private static void createExcel(List<Student> list) {
    // 創(chuàng)建一個(gè)Excel文件
    HSSFWorkbook workbook = new HSSFWorkbook();
    // 創(chuàng)建一個(gè)工作表
    HSSFSheet sheet = workbook.createSheet("學(xué)生表一");
    // 添加表頭行
    HSSFRow hssfRow = sheet.createRow(0);
    // 設(shè)置單元格格式居中
    HSSFCellStyle cellStyle = workbook.createCellStyle();
    cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);

    // 添加表頭內(nèi)容
    HSSFCell headCell = hssfRow.createCell(0);
    headCell.setCellValue("姓名");
    headCell.setCellStyle(cellStyle);

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

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

    // 添加數(shù)據(jù)內(nèi)容
    for (int i = 0; i < list.size(); i++) {
      hssfRow = sheet.createRow((int) i + 1);
      Student student = list.get(i);

      // 創(chuàng)建單元格，并設(shè)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();
    }
  }

  /**
   * 讀取Excel
   * 
   * @return 數(shù)據(jù)集合
   */
  private static List<Student> readExcel() {
    List<Student> list = new ArrayList<Student>();
    HSSFWorkbook workbook = null;

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

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

        // 將單元格中的內(nèi)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;
  }
}

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
        + "]";
  }
}

[Student [name=小明, age=8, grade=二年級(jí)], Student [name=小光, age=9, grade=三年級(jí)], Student [name=小花, age=10, grade=四年級(jí)]]