POI

public class Test {
    public static void main(String[] args) throws IOException {
        HSSFWorkbook wk=new HSSFWorkbook();
        HSSFSheet sheet=wk.createSheet("学生表");
        HSSFRow row=sheet.createRow(0);
        HSSFCell cell=row.createCell(0);
        cell.setCellValue("学生成绩表");
        sheet.addMergedRegion(new CellRangeAddress(0,0,0,2));
        HSSFRow row1=sheet.createRow(1);
        row1.createCell(0).setCellValue("学生编号");
        row1.createCell(1).setCellValue("学生姓名");
        row1.createCell(2).setCellValue("学生年龄");

        HSSFRow row2=sheet.createRow(2);
        row2.createCell(0).setCellValue("1");
        row2.createCell(1).setCellValue("刘振宇");
        row2.createCell(2).setCellValue("18");
        FileOutputStream outputStream=new FileOutputStream("d:\\workbook.xls");
        wk.write(outputStream);
        outputStream.flush();
    }

方法二：

创建实体类：

package cn.bdqn.poi;

/**
 * Created by 刘振宇 on 2017/8/28.
 */
public class entity {
    private Integer id;
    private String name;
    private Integer age;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

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

测试类：

public class Test {
    public static void main(String[] args) throws IOException {
        HSSFWorkbook wk=new HSSFWorkbook();
        HSSFSheet sheet=wk.createSheet("学生表");
        HSSFRow row=sheet.createRow(0);
     





        HSSFCell cell=row.createCell((short)0);
        cell.setCellValue("学生编号");
        cell=row.createCell(((short)1));
        cell.setCellValue("学生姓名");
        cell=row.createCell(((short)2));
        cell.setCellValue("学生年龄");
        List<entity>list=new ArrayList<entity>();
        entity entity=new entity();
        entity.setId(1);
        entity.setName("宇");
        entity.setAge(18);
        for (short i=0;i<list.size();i++){
            row=sheet.createRow(i+1);
            row.createCell(0).setCellValue(list.get(i).getId());
            row.createCell(1).setCellValue(list.get(i).getName());
            row.createCell(2).setCellValue(list.get(i).getAge());
        }
        FileOutputStream outputStream=new FileOutputStream("d:\\workbook.xls");
        wk.write(outputStream);
        outputStream.flush();
    }