Java解析，导出Excel文件（.xlsx跟.xls两种格式）&字体修改&单元格合并

package JavaBean;

public class Teacher {
    private String Email;
    private String Name;
    private String Password;
    private String Major;
    public Teacher(String Email,String Password,String Name,String Major) {
        this.Email=Email;
        this.Password=Password;
        this.Name=Name;
        this.Major=Major;
    }
    public String getEmail() {
        return Email;
    }
    public String getName() {
        return Name;
    }
    public String getPassword() {
        return Password;
    }
    public String getMajor() {
        return Major;
    }
    public String toString() {
        String information=String.format("Email:%s  Major:%s  Name:%s  Password:%s", this.Email,this.Major,this.Name,this.Password);
        return information;
    }
}

package Excel;

import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
/*
 * 该类用于对表格主题样式的设置
 */
public class Style {
    public static XSSFCellStyle createCellStyle(XSSFWorkbook workbook){
        XSSFFont font=workbook.createFont();
        //在对应的workbook中新建字体
        font.setFontName("微软雅黑");
        //字体微软雅黑
        font.setFontHeightInPoints((short)11);
        //设置字体大小
        XSSFCellStyle style=workbook.createCellStyle();
        //新建Cell字体
        style.setFont(font);
        return style;
    }
}

package Excel;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
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.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;



import JavaBean.Teacher;
/**
 * 
 * 该类用于教师于学生对应关系表格的读取.xlsx和输出.xlsx表格文件,同时也支持xls格式的Excel表格文件
 * 参考https://www.cnblogs.com/hhhshct/p/7255915.html
 */
public class TeacherTableEnhanced {
    private String filePath;//文件位置
    private final String outPutSheetName="学生预约系统教师信息";//Excel文件的标题
    public TeacherTableEnhanced(String filePath){//构造方法,Excel文件位置为参数
        this.filePath=filePath;
    }
    public List<Teacher> getFromExcel(){
        List<Teacher> teachers=null;
        try{
            Workbook wb =null;
            Sheet sheet = null;
            Row row = null;
            teachers =new ArrayList<Teacher>();
            wb = readExcel(filePath);//指定Excel对象
            if(wb != null){        
                //获取第一个表
                sheet = wb.getSheetAt(0);
                //获取最大行数
                int rownum = sheet.getPhysicalNumberOfRows();
                //获取最大列数
                String Email,Major,Name,Password;
                for (int i = 2; i<rownum; i++) {//这里从第三行开始读取数据
                    row = sheet.getRow(i);//获得制定行数
                    Cell cell0=row.getCell(0);//分别从每个格子中获取内容
                    Cell cell1=row.getCell(1);
                    Cell cell2=row.getCell(2);
                    Cell cell3=row.getCell(3);
                    cell0.setCellType(Cell.CELL_TYPE_STRING);
                    cell1.setCellType(Cell.CELL_TYPE_STRING);
                    cell2.setCellType(Cell.CELL_TYPE_STRING);
                    cell3.setCellType(Cell.CELL_TYPE_STRING);
                    //设置Excel内容为文本类型    ,不加执行不了
                    Email=cell0.toString();
                    Major=cell1.toString();
                    Name=cell2.toString();
                    Password=cell3.toString();//toString获得内容
                    teachers.add(new Teacher(Email, Password, Name, Major));
                }
            }
            
        }catch (Exception e) {
            System.out.print("文件格式不正确！");
            e.printStackTrace();
        }
        return teachers;
    }
    //读取excel
    public Workbook readExcel(String filePath){
         Workbook wb = null;
         if(filePath==null){
             return null;
         }
         String extString = filePath.substring(filePath.lastIndexOf("."));//获取文件格式
         InputStream is = null;
         try {
             is = new FileInputStream(filePath);
             if(".xls".equals(extString)){//判断Excel文件格式
                 return wb = new HSSFWorkbook(is);
             }else if(".xlsx".equals(extString)){
                 return wb = new XSSFWorkbook(is);
             }else{
                 return wb = null;
             }
         } catch (FileNotFoundException e) {
                e.printStackTrace();
         } catch (IOException e) {
                e.printStackTrace();
         }
         return wb;   
    }
    /**导出xlsx文件
     * https://www.2cto.com/kf/201605/510933.html
     * https://www.cnblogs.com/f-anything/p/5996380.html
     */
    public void outPutToAExcel(List<Teacher> teachers) throws IOException {
        XSSFWorkbook wb=new XSSFWorkbook();
        XSSFCellStyle style=Style.createCellStyle(wb);
        XSSFSheet sheet=wb.createSheet(outPutSheetName);
        //这里的是表格内像素的转换公式,例如第列宽24像素,第二列宽20像素等等..
        sheet.setColumnWidth(0, 256*24+184);//sheet.setColumnWidth(0, 256*width+184);http://blog.csdn.net/duqian42707/article/details/51491312
        sheet.setColumnWidth(1, 256*20+184);
        sheet.setColumnWidth(2, 256*10+184);
        sheet.setColumnWidth(3, 256*10+184);
        //合并第一行
        CellRangeAddress region1 = new CellRangeAddress(0, 0, (short) 0, (short) 3); //参数1：起始行 参数2：终止行 参数3：起始列 参数4：终止列   
        sheet.addMergedRegion(region1);//合并单元格
        XSSFCell cell_=sheet.createRow(0).createCell(0);
        cell_.setCellStyle(style);
        cell_.setCellValue("                                  学生预约系统教师账号信息");//手动居中~
        //输出表头,即第一行
        XSSFRow row=null;
        XSSFCell cell0_,cell1_,cell2_,cell3_;
        XSSFRow row0=sheet.createRow((int)1);
        XSSFCell cell0=row0.createCell(0);
        XSSFCell cell1=row0.createCell(1);
        XSSFCell cell2=row0.createCell(2);
        XSSFCell cell3=row0.createCell(3);
        //表格样式
        cell0.setCellStyle(style);
        cell1.setCellStyle(style);
        cell2.setCellStyle(style);
        cell3.setCellStyle(style);
        cell0.setCellValue("邮箱账号");
        cell1.setCellValue("学科专业");
        cell2.setCellValue("教师姓名");
        cell3.setCellValue("账号密码");
        for(int i=0;i<teachers.size();i++){
            row=sheet.createRow(i+2);
            cell0_=row.createCell(0);
            cell1_=row.createCell(1);
            cell2_=row.createCell(2);
            cell3_=row.createCell(3);
            cell0_.setCellStyle(style);
            cell1_.setCellStyle(style);
            cell2_.setCellStyle(style);
            cell3_.setCellStyle(style);
            cell0_.setCellValue(teachers.get(i).getEmail());
            cell1_.setCellValue(teachers.get(i).getMajor());
            cell2_.setCellValue(teachers.get(i).getName());    
            cell3_.setCellValue(teachers.get(i).getPassword());
        }
        try{
            FileOutputStream outputStream=new FileOutputStream(filePath);
            wb.write(outputStream);
            wb.close();
            outputStream.flush();
            outputStream.close();
        } catch (FileNotFoundException e){
            System.err.println("获取不到位置");
            e.printStackTrace();
        } catch (IOException e){
            e.printStackTrace();
        }
    }
    public static void main(String[] args) throws IOException {
        //导出Excel测试
        TeacherTableEnhanced one=new TeacherTableEnhanced("C:/Users/XPS/Desktop/教师表格.xlsx");//这里需要输入导出的地址
        List<Teacher> teachers=new ArrayList<Teacher>();
        Teacher a=new Teacher("111@qq.com", "123456", "Eason", "Computer Science");
        teachers.add(a);
        one.outPutToAExcel(teachers);
        
        
        //导入Excel测试
//        TeacherTableEnhanced one=new TeacherTableEnhanced("C:/Users/XPS/Desktop/教师表格.xlsx");//这里需要输入导入的地址
//        List<Teacher> teachers=one.getFromExcel();//从Excel文件中获取List
//        for(Teacher a:teachers){
//            System.out.println(a);
//        }
    }

}